Development of engineering geology in western united states

Engineering Geology 59 (2001) 1±49
www.elsevier.nl/locate/enggeo

Development of engineering geology in western United States
George A. Kiersch a,b,*
a
Professor Emeritus, Cornell University, Ithaca, NY 14853, USA
b
Kiersch Associates, GeoScience Consultants, 4750 Camino Luz, AZ 85718, USA

Abstract
Geologic concepts and scienti®c-technical guidance for the planning-design and construction of engineered works was
recognized in Europe by the 1800s and by the early 1900s in North America. This early geologic knowledge and experience
provided the rudimentary principles that guided practitioners of the 19th century in serving the emerging projects in western
United States. Case studies review the scienti®c-technical lessons learned and the legacy of geologic principles established in
the planning and construction of major civil, mining, and military engineered works in the western states. These contributions to
GeoScience knowledge and engineering geology practice include:

² Tunnels and aqueducts across active fault zones, beneath young volcanic features, groundwater-charged faults, and land
subsidence mitigation.
² Controversial foundation design, Folsom and Auburn dams, Golden Gate Bridge.
² Protective underground construction chambers, safety dependent geologic setting.
² Geologic mapping as database management leasing, maintenance railroad trackway.
² Causeway Great Salt Lake, geo-risks calculated, mitigated `as-constructed'.
² Nuclear powerplants seismic design.
² Urban Land-Use, on-going processes, acceptable geo-risks.
² Dwelling Insurance, insuree's responsibilities.
² Selecting technique/method to mitigate risk, preferably based on extensive database, evaluation of characteristics and
historical origin adverse features/conditions that constitute a geo-risk.

q 2001 Elsevier Science B.V. All rights reserved.
Keywords: Lessons learned Ð geoscience legacies; Principles of practice; Natural processes Ð acceptable geo-risks; Aqueducts/tunnels Ð
active faults; In¯ow groundwater; Dam foundations Ð concrete/earth®ll; Golden Gate Bridge; Nuclear plants; Land-use risks; Protective
underground construction; Railroad causeway; Calculated risks; Landslide destruction; Insuree's responsibilities; Drill-core Ð inadequate
interpretation; Impacts tunnel design; Mining method; Unit-bid prices; Safety

1. Introduction mining on the Sinai Peninsula over 15,000 years ago
(Stone Age), and tunneling (adit) was started about
1.1. Historical `engineered' works 3500 BC.
Initially, `geologic' craft and lore was utilized to
The history of remarkable engineering construction evaluate natural sites and the remnants of remarkable
feats is as old as man's records that began with copper construction feats are a legacy to these early skills.
Use of `geologists` to evaluate natural risks and sites
* 400 Prospect St., Apt. 234, La Jolla, CA 92037, USA. for engineered works has a long history that
0013-7952/01/$ - see front matter q 2001 Elsevier Science B.V. All rights reserved.
PII: S 0013-795 2(00)00063-6

2 G.A. Kiersch / Engineering Geology 59 (2001) 1±49

developed from the lore of our forefathers: Leonardo project demands of the mid- to the late-1800s. By the
da Vinci (Faul and Faul, 1983; Clements, 1981), Henri 1900s, the activities of applied geological practi-
Gautier (1721) and William Smith (Adams, 1938). In tioners in North America were of a scope and
North America early assistance, geological insight acceptance-level to their counterparts in Europe.
and counsel for engineering purposes was fostered
by a small group of practitioners. However, any over-
view of these early efforts for projects in the western 2. Early projects and practitioners
states bene®ted from the substantial legacy of experi-
ence and knowledge acquired earlier by pioneers in 2.1. Introduction
Europe and Asia.
The brief case-reviews of milestone engineering Professor William O. Crosby of the Massachusetts
projects and the rudimentary geologic principles and Institute of Technology offered the ®rst continuous
concepts that follow are more fully described in the training with lectures and a syllabus text on geology
recent Heritage volume (Kiersch, 1991). The emphasis and engineering in 1893 (Kiersch, 1991, p. 23). The
is on Ð `How and in what way have the efforts of ®rst formal lectures on `Geology for Engineering
engineering geology practitioners resulted in scienti- Students' were given in 1875±1876 by Theodore B.
®c-technical advances in the GeoSciences, while Comstock at Cornell. Professor R.S. Tarr included the
protecting the safety, health, and welfare of the public?' subject in his Practical/Dynamic Geology course at
Cornell in 1894, and by 1898 with Heinrich Ries
1.2. Early concepts Ð engineers accept geologic they offered three geology courses for engineering
counsel students. This led to the early `Engineering Geology'
text by Ries and Watson (1914, 1936).
The concept that geologic conditions can in¯uence Crosby became the leading practitioner and consul-
the planning and construction of large-scale engi- tant for engineered works (1893±1925) and is consid-
neered works, such as roads, canals, tunnels, and ered the `Father of Engineering Geology in North
water supplies, was recognized during the eighteenth America' (Kiersch, 1991, pp. 44±45). He was the
century in Europe and by the nineteenth century in ®rst to serve as a consulting geologist for: the US
North America. Bureau Reclamation (Arrow Dam, Idaho); the US
The application of geology for engineering Army Engineers (Muscle Shoals Dam, Tennessee);
purposes played a small role in the early history and the Board of Water Supply New York City; and for
expansion of the United States up to the 1880s, as some 50 other dams and tunnel projects in States, as
documented by Radbruch-Hall (1987). Accordingly, well as projects in Spain, Mexico, and Canada. In
America's westward expansion by the 1820s initiated California, Crosby served as a consultant for early
the construction of an improved network of roads and dams on the Feather River during 1920s, e.g. Big
canals. Yet suddenly in the middle of the century, road Bend and Meadows Dams for Great Western Power
and canal building was curtailed in favor of construct- Co. (forerunner P.G.E.).
ing a nationwide railroad network (1850s±1870s). The innovative investigation of the Boston Harbor
This rush to western lands and the Paci®c region environs by Professor W.O. Crosby a century ago
required bold planning and unusual human efforts to (1900±1903) warrants study by today's aspiring
complete rail links with the central states. practitioners (Cozort, 1981, pp. 203±212). The
Historically the early geologic concepts and proposed Charles River Dam, Boston was of deep
principles that assisted the builders of engineered concern to the chief engineer, Freeman (1903).
works in North America were largely due to the Would damming the river estuary system allow the
accomplishments and scienti®c-technical advances preservation of the shoals and natural channels of
of European investigators in the eighteenth and nine- Boston Harbor, or conversely would the dam change
teenth centuries. These European experiences and the harbor? Crosby's investigation of the Charles
proven principles were available to North American River basin, other coastal estuaries, and offshore
geologists and engineers when called on to serve the islands concluded that surging of the tidal prism did

G.A. Kiersch / Engineering Geology 59 (2001) 1±49 3

Fig. 1. Boulder (Hoover) Dam site under construction in the early 1930s. Note diversion tunnels in each abutment, and blasting for the keyway
of the dam in volcanic rocks (photo courtesy of the Heinrich Ries collection, Cornell University).

more to shoal the harbor than deepen it. The dam for an accurate description and classi®cation of rock
would not cause environmental changes and his units involved in engineering contracts (Hall, 1839)
conclusions of 1903 have proved correct. and landslides (Mather and Whittlesey, 1838).
Gilbert (1884) was the ®rst modern geologist in Professor Warren J. Mead, a pioneer in teaching the
North America to relate the principles of mathe- applications of geology to engineering students at
matics, physics, and engineering to the solution of Wisconsin and MIT, was known worldwide for his
geological problems (Wallace, 1980); he seemed to research and geological expertise (Shrock, 1977, p.
solve puzzles in the manner of an engineer. For 692). His studies on rock properties and failure
example, Gilbert (1909) was one of the ®rst to mechanisms (Mead, 1925, 1930) established early
investigate forecasting of earthquakes. His studies principles relative to stress and a rock mass which
of sediment transport in running water (Gilbert, constituted the forefront of thinking on `rock
1914) and debris ¯ows as related to the mining mechanics' in the 1920s. As a consultant on Boulder
debris of the Sierra Nevada (1917) together estab- Dam, he demonstrated that minimal support only was
lished engineering geology principles practiced required throughout the four diversion tunnels
today. Even more fundamental was Gilbert's identi- (Fig. 1), an early ®rst that lowered tunnel-construction
®cation of the subsidence and rebound phenomena costs on many subsequent projects.
associated with loading and unloading of ancient Kirk Bryan spent many years on ®eld-oriented
Lake Bonneville, a concept critical to the design- projects in the western states with the US Geological
operation of many engineered works (Yochelson, Survey and was an early author on the `Geology of
1984). The physical properties of rock masses were reservoir and dam sites' (Bryan, 1929; AIME, 1929).
recognized in a very early paper concerning the need Later Bryan (1939), recognized that three distinct


Fig. 2. The San Andreas fault zone, strike-slip movement of 1906 in Marin County, California is cited by Reid (1911) in his concept of elastic
rebound (from Heinrich Ries collection, Cornell University, in Kiersch, 1991, p. 33).

geologic uncertainties are critical to planning- fundamentals of sur®cial geology to engineering
operating engineered works: (1) control of natural students at the Stanford University (Branner, 1898)
agents, processes, and phenomena; (2) stability and and consultant on St. Francis dam (1925). Later,
durability of rock masses; and (3) the control of Professor Bailey Willis on numerous projects, e.g.
ground-water circulation, permeability and ¯ow of Golden Gate Bridge controversy. Professor Andrew
¯uids. Similarly, Twenhofel (1932, 1939) was C. Lawson, UC-Berkeley served many engineering
another early contributor to the geological literature related projects, such as the evaluation of San Francisco
for applied geologists with geological treatises on earthquake damage in 1906; preparation of USGS folio
sedimentation. These volumes described the proper- on City of San Francisco; construction UC-Memorial
ties of soft, unconsolidated, and soil-like deposits stadium with inclusion of design for displacement of
common to engineering sites. foundation by the Hayward fault; and the stability
Other early consultants and engineering geology controversy serpentine rock surrounding Golden Gate
practitioners in the Western States were prominent Bridge construction with A.E. Sedgwich, USC-Los
contributors to the knowledge and growth of geology Angeles. Professor G.D. Louderback, UC-Berkeley,
for engineered works prior to 1940. This group was consultant on damsites for Federal and State agen-
included: Professor John C. Branner who taught the cies as was Professor John P. Buwalda (Buwalda, 1951),


California Institute of Technology. Chester Marliave, a (Richter, 1966). An early major earthquake affected
private consultant served such projects as Folsom dam a wide area around the San Francisco Bay area in
and Broadway tunnel, San Francisco, and Haiwee dam 1868, but little is known or on record. Right-lateral
for Los Angeles Water and Power. movement occurred along the now-designated
Hayward fault that destroyed the village of Hayward
2.2. Urban planning Ð mapping of cities as reported by George Davidson (US Coast Survey).
Lawson in 1908 reported that authorities at the time
Circa 1900, the US Geological Survey formu-
feared the release of data on the earthquake and the
lated an ambitious program to topographically and
severity of damage would hurt the reputation of the
geologically map a group of major cities. The map
San Francisco Bay area and suppressed the report. No
folios were released with supporting information
copies of a report on this Hayward-fault event are on
on the surface and subsurface `environmental'
record. At UC-Berkeley campus the Hayward fault
features and provided a terrain evaluation database
crosses beneath the Memorial football stadium
for the expected urban expansion and construction.
which was built in two separate halves; the structure
This series began with such cities as the Sacramento
can shift laterally without major damage should
folio by Lindgren (1894) and the San Francisco folio
movement occur on the fault. The regional geologic
by Lawson (1914).
processes active in the San Francisco Bay area have
2.3. EarthquakesÐresearch and forecasting been studied for decades; risks from geologic and
man-made conditions are summarized in Fig. 3A
World attention was directed to a major branch of and B and show a correlation between the 1906 and
engineering geology interest by the great earthquake 1989 earthquake damage (Fig. 4) in the Marina
disaster in San Francisco, California, on 18 April District of San Francisco.
1906. Reports by the US Geological Survey (Gilbert Much progress in the ®eld of engineering seismol-
et al., 1907) and the Carnegie Institution (Lawson, ogy is due to the efforts of scientists and engineers in
1908) on this cataclysm are classic in their scope California; they founded the Seismology Society of
and thoroughness. All geologic phases were covered America in 1907 and committees of American Society
in the reports including the effects of shock intensity of Civil Engineers reported on earthquake effects
on various rock and soil foundations. This event from 1907 to 1925. The major Santa Barbara earth-
awakened the engineering profession to the potential quake occurred in California on 1 July 1925, soon
importance of a natural phenomena and the need for after the Congressional Act of January 1925, which
constraints which have commanded the attention of authorized the US Coast and Geodetic Survey to make
many engineering geologists, e.g. the shock intensity investigations and release seismological reports. This
on marshlands and saturated, man-made ®ll are far milestone act was the beginning of our current meth-
greater than on rocky hills and natural, well-drained ods of earthquake engineering studies in the United
soils (Engle, 1952) and such engineered structures are States. Since another major earthquake in 1933 at
so modi®ed in design. Reid (1911) developed the Long Beach, California, research in earthquake engi-
concepts of elastic rebound and strike-slip move- neering has advanced at an ever-accelerating pace.
ment from observation along the San Andreas The ®rst records of strong earthquake movements
fault zone, a milestone in understanding the causes obtained from the Long Beach earthquake (Neumann,
of seismic events (Fig. 2). The widely circulated 1952) led to the strengthening the building codes, e.g.
photograph of a barn and manure pile torn apart the Field act.
by lateral movement (Kiersch, 1991, p. 31) illus-
trates the slip-displacement common to the San 2.4. Railroads across western territory, 1850s±1870s
Andreas fault zone.
The historic record of earthquakes in California The discovery of gold at Sutter's Mill in California
dates back to 1769, but only since the early 1930s in 1848 sparked a frenzied migration across the
have earthquake studies become oriented to the safe nearly trackless western territories that was with-
and economical design of engineering structures out precedent in this country's history. So rapid


Fig. 3. (A) An early seismic zonation map of the San Francisco area, based on relative intensities felt throughout the city during the 1906
earthquake. (B) Note the correspondence between sur®cial materials and felt intensities (from Borcherdt, 1975).

was the settlement of the West Coast, with a hub coast, but also aid in the settlement of selective
city on the San Francisco Bay, that railways were broad regions between the Mississippi River and
proposed to cross the entire continent. The rail Paci®c Ocean; a brief summary after Radbruch-
lines would not only serve the population on the Hall (1987) follows.


Fig. 3. (continued)

2.5. Land grants encourage construction of railroads; grants had gone
to 12 states by 1862 (DeFord, 1954, p. 4). The ®rst
The federal government gave land grants in 1850 to western land grant was made to the Union Paci®c and
the states of Illinois, Mississippi and Alabama to Central Paci®c Railroads on 1 July 1862, to build a

8
G.A. Kiersch / Engineering Geology 59 (2001) 1±49
Fig. 4. Vertical velocities during a magnitude 4.6 aftershock of the Loma Prieta earthquake of 17 October, as recorded 21 October 1989, at the three temporary seismograph stations
in the Marina district of San Francisco. Note comparative ampli®cation of ground motion in damaged (LMS) and undamaged (PUC) areas, and areas of bedrock (MAS) (modi®ed
from Plafker and Galloway, 1989 in Kiersch, 1991, p. 374).


Fig. 5. Grant lands and associated areas of California, Nevada, Utah, mapped by regional geologic survey of the Southern Paci®c Corporation,
1955±1961. Extent of the original Central (Southern) Paci®c land grants of 1862±1871 is inferred; parts disposed of prior to 1949 are based on
a 1909 survey (from Kiersch, 1991, p. 369).

transcontinental line from the Missouri River to the granted the Central Paci®c Railroad a right-of-way
Paci®c Ocean via Nebraska and Wyoming (UP) and and alternate odd sections of land for 20 miles on
connect with a line (CP) across California, Nevada, each side of the railroad from Roseville, California
and Utah (Fig. 5). A Congressional Act, 25 July 1866, to the Oregon border; and a second act on 27 July


1866, granted the Southern Paci®c Railroad a similar a professor of geology at the University of Texas
strip from Needles, California, to San Jose, via and Director Third Texas Geological Survey
Coalinga. Another act of 1871 granted alternate (1888±1894).
odd-section holdings to the Southern Paci®c Railroad The principal objective of the survey was to select
from the Tehachapi Pass near Mojave, California all lands for patent that were considered nonmineral
southward to Yuma, Arizona (Fig. 5). Similar grants and negotiate the release of known mineral-bearing
were made to the other western railroads in 1864, 1866, lands. Although the survey was active between 1909
and 1871; Santa Fe Railroad across northern New and 1925, SPCo had organized an active geological
Mexico and Arizona, the Northern Paci®c Railroad group in 1897 under consultant E.T. Dumble to
across Dakotas, Montana and Washington State. Only oversee operation of Rio Bravo Oil Company and
lands with coal and iron were retained by the govern- other coal and oil interests. The geological staff
ment (Henry, 1945). The land grants and rail lines were responsible for many pioneering ®rsts in the
across the barren `wastelands' of that day enhanced application of geology for industrial exploration that
their value and the tax revenue from railroad real estate included: techniques for geological logging of core-
became a major source of local income. hole cuttings; correlation of subsurface data between
By 1867, developing industries in America were wells within a ®eld; use of micro-paleontology as an
making radical demands on the nation's natural exploration tool, and other techniques in the 1910s
resources. Congress reacted and funded western geolo- (Underwood, 1964). Many well-known California
gical explorations. The Fortieth Parallel survey, was geologists served on this early survey: J.T. Taff,
authorized in 1867, to explore routes for the transcon- S.H. Jester, F.S. Hudson, D. Clark, L. Melhase,
tinental railroad (UP/CP) under direction of Clarence W.L. Moody, and C.L. Cunningham.
King and the US Army Engineers. An earlier survey The survey identi®ed the Coalinga region of
(US War Department 1856) explored several routes for California by 1920 as lands with an excellent potential
a railroad from Mississippi River to Paci®c Ocean in for petroleum. These SPCo lands were subsequently
1853±1854. After three successful years the King acquired by a rising new company, Standard Oil of
survey was placed under the Secretary of the Interior California (Chevron today), and the Coalinga area
in 1870 (King, 1880). Three other surveys followed, became its principal producing ®eld for over two
led by F.V. Hayden, Lt. George Wheeler, and Major decades. Several geologists associated with SPCo's
John Wesley Powell's exploration of the unknown survey became the nucleus of Standard's exploration
Colorado River Canyonlands. All four surveys were staff; and S.H. Jester became chief geologist, serving
under the control of Congress by 1874, which led to into the 1940s.
establishing the US Geological Survey in 1879.
2.7. Aqueducts for Los Angeles area
2.6. Geological survey Ð Southern Paci®c lands
1909±1920s During the 1900s, a major water-supply system was
undertaken for the greater Los Angeles area. The ®rst
The western railroad land grants of 1862±1871 Owens River aqueduct was constructed in 1907±1913
initiated little controversy over mineral rights and by the Department of Water and Power, Los Angeles
land values until 1900s when industrial development (LADWP). These works accomplished many `®rsts'
brought railroad land holdings into the spotlight. As in engineering geology practice with respect to
an outgrowth, a far-sighted geological and mineral tunneling and excavation through active fault zones,
evaluation of the Southern Paci®c grant lands was as did the later construction of the Mono Basin exten-
undertaken in 1909 under D.T. Dumble, formerly sion between 1934 and 1940 (Fig. 6). Los Angeles

Fig. 6. Map of the Los Angeles Aqueduct system, Los Angeles to Owens River sector completed in 1913. Mono Basin extensions northward
completed in 1941 with intake at Lee Vining. The Second Aqueduct project completed in 1969 parallels the original aqueduct system, begins
with an intake south of Owens Dry Lake/Olancha. This water-supply network of tunnels, canals, dams, and powerhouses crosses many active
fault zones in the eastern Sierra Nevada and Los Angeles region (from Kiersch, 1991, p. 27).


purchased 307,000 acres in Inyo and Mono Counties high ¯ow of carbon dioxide gas in an area of calcar-
to protect the water rights that supplied the aqueduct. eous rocks (nearby volcanic activity); and squeezing
The drama, intrigue, and legal maneuvers by the land- and ¯owing ground at the fault contacts between
owners to retain the water and by the builders metamorphic and granitic rocks where the deeply
(LADWP) to gain the water rights and the right-of- weathered material air-slaked on exposure.
way for construction were depicted in the movie
Chinatown in the 1970s. The Second Los Angeles 2.8. Western dams
aqueduct, constructed in 1965±1970, increased
The Reclamation Act of 1902 authorized the
water delivered to city by 50% (Fig. 6).
federal government to start a reclamation and irriga-
The ®rst aqueduct of 375 km tapped the fresh
tion program in the western United States under the
waters of the Owens River that ¯owed into saline
Reclamation Service, an agency separated from the
Owens Lake; the later Mono Basin extension (1940)
US Geological Survey Hydrologic Branch in 1907,
extended the system 170 km northward for a total of
and designated the Bureau of Reclamation in 1923.
545 km (Fig. 6). This system of engineered works
One of the earliest irrigation projects to be authorized
consists of more than 100 tunnels (120 km), many
was the development of the Salt River in Arizona, of
dams and powerhouses, and more than 400 km of
which Roosevelt Dam (1906±1911) was the ®rst
con®ned, or open canal ¯ow. The tunnels and canals
project. The principal investigation of the site was
have required continued maintenance owing to the
by drilling several holes in the channel section; the
numerous fault zones crossed and the varied/contrast-
good-quality foundation of sandstone and quartzite
ing rock conditions.
required very little excavation. Roosevelt Dam and
The Elizabeth tunnel, part of the original 1913
most of the other early dam projects had little
aqueduct, carries water from the Fairmount Reservoir
occasion to call on geologic counsel Ð the good-
across a ridge and the San Andreas fault zone and
quality, natural sites available accommodated the
discharges into a canyon for hydroelectric plants
moderate-height dams. Interestingly, Roosevelt Dam
downstream. The horseshoe-shaped pressure tunnel,
was an early `Old Dam' to undergo rehabilitation and
8 km long, is mainly in granitic rock that varies
modi®cation in 1988 (Fig. 22).
from a hard to an altered and thoroughly crushed
The Arrow Dam in Idaho was another early Bureau
rock mass. The active San Andreas fault zone (about
of Reclamation project that was followed by many
1.5 km wide) is crossed orthogonally by the tunnel,
large-scale dam projects of 1920s±1980s. The most
another early `®rst' in applied geology. This sub-
widely known Boulder/Hoover Dam on Colorado
surface exposure of the active fault zone has been
River near Las Vegas, Nevada was a professional
widely used for scienti®c research; no signi®cant
milestone in the acceptance of geologic guidance for
movement or damage to the tunnel has been reported
planning and construction of major engineered works.
to date (Wilson and Mayeda, 1966; Proctor, 1999).
The Mono Craters tunnel of 1934±1940 experi- 2.9. Boulder/Hoover dam
enced a series of different geological problems, as
described by Wilson and Mayeda (1966). The tunnel, On 12 March 1928, the dramatic and complete
18 km long (3 m diameter), pierces the volcanic necks failure, within a few minutes, of the St. Francis
that underlie the Mono Craters and some 20 inactive dam near Saugus, California, was a convincing
volcanic pumice cinder cones between Mono Basin disaster in the history of large engineering struc-
and Long Valley. Excavation required ®ve and a half tures. One repercussion was a symposium (AIME,
years from six headings; 67% of the tunnel is 1929) to consider problems of dam and reservoir
supported due to the wide variety of rocks penetrated, geology, that directed attention to the importance
i.e. mainly rhyolite, tuff, volcanic ash, granite, meta- of adequate geological investigations and counsel
morphics, sandstone, glacial deposits, lake beds, and in erecting dams. The results, which were widely
alluvium. Nearly every serious dif®culty inherent to publicized, focused attention on the importance of
tunneling occurred: exceptional volumes of water geology as an indispensable aid in civil engineer-
under high pressure with ¯ows to 35,000 gpm; a ing (Kiersch, 1955, p. 23).


Reverberations of the St. Francis disaster intensi- Central Valley plan along with the Delta±Mendota
®ed the differences of opinion and uncertainties Canal that moves San Joaquin River water southward
concerning construction of a proposed high dam at from a pumping station near Tracy for irrigation usage
Boulder Canyon on the Colorado River. Finally, to in the Mendota-region.
appease all parties concerned, Congress, on 29 May The US Army Corps of Engineers was authorized
1928, authorized the Secretary of the Interior to to build ¯ood control dams and related works in many
appoint a board of ®ve eminent engineers and geolo- western states by the Flood Control Act of 1936.
gists to examine the proposed site of the dam and Bonneville Dam on the Columbia River, Oregon-
advise as to matters affecting the safety, economic Washington was a major early project followed by
and engineering feasibility, and adequacy of the other dams upstream. A series of ¯ood control dams
proposed structure (USBR, 1950, p. 11). The two were built in Central California on rivers ¯owing into
geologists on this board were Charles P. Berkey and the Central Valley beginning in 1940s with: Pine Flat
Warren J. Mead. The board's recommendations are dam on the Kings River; Isabella Dam on Kern River;
now history, yet, ironically, it required an engineering Success Dam on Tule River at Porterville; and the
failure and catastrophe (St. Francis dam) to gain due Folsom project east of Sacramento on the American
recognition of the importance geologic conditions River. Folsom was the ®rst joint-undertaking by the
may attain in large-scale construction projects. Corps of Engineers and Bureau of Reclamation for
Oddly, these events led to the ®nal authorization and ¯ood control and power generation facilities under
construction of the world's highest dam (726 ft) at the `Folsom Formula' legislation in 1949 (exploration
that date. The major recommendations of the board and construction geology described below).
members in 1928 proved engineering wise and
economically sound, and many `®rsts' in engineering
geology were recorded at Boulder dam, among them 2.10. Attitudes change among engineers re: geology
was F.A. Nickell the ®rst resident geologist, on a
Bureau project. The St. Francis dam catastrophe By the 1930s, the civil engineering profession
and public's concern resulted in State of California realized the need for greater geological input and
establishing an of®ce, Supervisor of Safety of Dams guidance for major works. Unfortunately, geological
in 1929. science did not respond immediately to the requests of
The USBR constructed the Grand Coulee dam on the civil engineers for an improved knowledge of the
Columbia River, Washington (1933±1942) in a glacial physical properties of rocks and/or soft, unconsolidated
scoured, complex geologic environs of extensively sediments and soils. Consequently, civil engineers
jointed/fractured fresh granitic rock and associated themselves began to provide input. A leader among
glacial deposits (Irwin, 1938). They also undertook the group of concerned engineers was Karl Terzaghi,
construction of Parker dam downstream from Boulder an early specialist in earth materials. He worked for
dam on Colorado River. This project became the the US Reclamation Service from 1912 to 1915, but
deepest concrete dam below the riverbed (233 ft. to returned to Europe to advance the combined ®elds of
bedrock) and only 87 ft. above; the concrete experi- soil mechanics and geology for engineered works as
enced an early case of cement-aggregate reaction and professor at Roberts College, Constantinople and the
sur®cial cracking. Technical Hochschule, Vienna. He returned to America
Subsequently, the USBR undertook construction of as Professor of Foundation Engineering at Harvard
Shasta Dam on the upper Sacramento River in (1938±1963) and served as a prominent consultant for
northern California (1938±1943) a key unit of engineered works in North America. Terzaghi based his
Bureau's California Central Valley plan. The dam soil mechanics techniques on sound geological
foundation of intruded metamorphic rocks is traversed knowledge (Terzaghi, 1955) and believed every soil-
by a variety of faults and shear zones with associated mechanics specialists (`geotechnical' today) should be
joints and altered materials. During this period the half geologist; a combination he acknowledged later had
Friant Dam on San Joaquin River east of Fresno was not been followed by his successors, and was a major
undertaken. It is the southern link in the Bureau's professional disappointment (Terzaghi, 1963). Reviews


of Terzaghi's accomplishments are given by Goodman of some sandstones induced swelling and squeezing;
(1999) and Shlemon (1999). and dif®culty dealing with substantial quantities of
During the early 1900s, Homer Hamlin ®rst methane and sulfuretted hydrogen gas (McAfee,
engaged in geology and then in engineering for 1934). These problems served to develop the use of
several large California municipalities, and became gunite as a sublining to control-support in squeezing
one of the early engineer-geologists. Ultimately, his ground. Some faults traversed by the tunnel are now
studies for municipalities on control of the Colorado known to be active.
River culminated in a 1920 proposal to put a dam in
Boulder Canyon Ð a site later used for Hoover Dam 2.13. Broadway tunnel, Berkeley Hills, 1935±1937
(Nickell, 1942). Another early geologist involved
with the investigation of dam sites along the Colorado Another early northern California tunnel that also
River in the 1920s was Sidney Paige, who became an in¯uenced engineering geology practice was the twin-
eminent practitioner of engineering geology from the bore highway tunnel through the Berkeley Hills that
1930s to 1950s (Paige, 1950). links the Orinda and Walnut Creek areas to the East
Bay and San Francisco Bay bridge. Benjamin M.
2.11. Highway construction materials Ð early Page, of Stanford, served as geologist for the contrac-
investigations tor and described the tunneling dif®culties largely due
to the unexpected geological conditions encountered
The use of geologists to locate sources of adequate
(Page, 1950). The Miocene±Pliocene rocks involved
materials and provide guidance in planning routes for
consist of sandstone, shaley sandstone, shale,
the developing nationwide highway system became a
mudstone and conglomerate. Part of the tunnel
major category of applied geology in the early 1900s.
cross-cut an overturned limb of a syncline and the
By the year 1918, some 50 papers on geology as
folded beds with dips up to 608 were fractured and
applied to highway engineering had been published
displaced by the many associated faults.
in America (Huntting, 1945). This included the road-
Although a pre-construction geologic investigation
material sources of 24 states and reports on the
and report was made by a prominent Berkeley
relation of mineral composition to the engineering
geologist, it re¯ected no serious concerns. In reality,
characteristics of the rock. An early report by Pearson
the `as-encountered' tunneling conditions presented
and Loughlin (1923) of a concrete failure traced the
serious dif®culties and work stoppages owing to:
cause to a cement-aggregate reaction from a source in
lateral pressures active at the southwest portal;
San Gabriel Mountains, California. Reactive-aggre-
instability and `running ground' with `cave-ins';
gate became a serious problem in highway pavements
unstable contacts between some bedded rock units;
and caused cracking on concrete surfaces at Parker
and treacherously weak and altered plastic diabase
Dam on Colorado River. Soon thereafter methods
dikes. The construction contract by The Six Companies
were devised to counteract the causes (McConnel et
(builders Boulder Dam), was canceled by the California
al., 1950).
Highway District due to slow progress in 1936, and
2.12. Hetch Hetchy aqueduct, 1927±1934 the tunnel was completed in 1937 by a replacement
contractor. This action led to a major lawsuit in which
Another early water supply project, the Hetch `Six Companies' contended that the inaccurate pre-
Hetchy aqueduct serving San Francisco, in¯uenced construction geologic report was a major cause of
engineering geology practice. The alignment required their slow progress (unexpected adverse rock condi-
a Coast Range tunnel 46 km long, the ®rst long-bore tions). The California Highway District contended
tunnel driven in the Paci®c Coastal region. Very dif®- they assumed no responsibility for the accuracy or
cult rock conditions were encountered in tunneling views of the geologist. The Court accepted this
from near Wesley in Central Valley to the outskirts proviso (no accountability) and `Six Companies'
of Livermore that included: active rock stresses in was denied any consideration for the misleading
which parts required realignment due to the highly pre-bid report and thus lost the suit.
contorted and sheared sediments; the clayey matrix This pioneer tunnel in the East Bay Hills provided


extensive geologic information and a database of more than a generation (Henderson, 1951, oral
great assistance in planning-design of the Bay Area communication; Proctor, 1999).
Rapid Transit (BART) system tunnel built nearby in
1960s. 2.15. Golden Gate Bridge controversy, 1931±1934

2.14. San Jacinto tunnel of Colorado River aqueduct, Engineers were aware of the need for geological
1934±1936 input into the planning and design of major works
by the 1930s. Yet, this guidance could interject
The San Jacinto tunnel driven through the San confusion and adverse effects into the planning
Jacinto Mountains experienced serious setbacks in and construction, if the geological conditions were
the early stages of construction due to geologic condi- misinterpreted. Often meddlesome or adversarial
tions largely unknown to the contractor (Henderson, approaches to planning a project are advanced by an
1939). This experience emphasized the seriousness intervenor/group, who have invested minimal tech-
and challenges associated with driving a large-size nical effort to support their concepts and accusations.
tunnel through a highly faulted mountain range with Such intervention can require the project's owner to
known active faults and minimal `as-is' geologic perform additional exploration, prepare arguments
information. Some fault zones caused costly delays and special reports to counter the criticism; frequently
and experienced enormous water in¯ows, from 7500 public hearings are held to resolve the issues Ð a
to 16,000 gpm at one location. The San Jacinto costly and time-consuming effort for the project
experience con®rmed the necessity for a suitable sponsor. Use of scienti®c and engineering concepts
pre-construction geological investigation to establish by intervenors became popular in the 1950s±1980s
the least hazardous tunnel alignment and a construc- during the construction and/or licensing of nuclear
tion plan. For example, approaching the fault zone power plants in North America.
from the hanging-wall side can control the ground- A much earlier case of intervenor opposition
water in¯ow from a fault zone into an advancing occurred in the exploration for and design of the foun-
tunnel heading. This allows a more gradual in¯ow dation for the South Pier of the Golden Gate Bridge,
of water at the tunnel face to drain from the inter- San Francisco, during 1931±1934 (Lutgens et al.,
connected fractures of the zone, before the tunneling 1934; Strauss, 1938; Schlocker, 1974). Opposition
advances and passes through the fault zone. The to the Golden Gate Bridge was supported by some
original San Jacinto alignment was changed after San Francisco area corporate interests and citizen
detailed geologic mapping located and evaluated 21 groups alike with public challenges in the 1920s and
fault zones; the new alignment intersected only 11 early 1930s which delayed the construction.
zones. Other measures used to reduce risks and One accusation contended that foundation condi-
tunneling costs included: drilling `feeler' holes tions for the South Pier were unsafe and a redesign
ahead of face; placing small pioneer bores ahead of was required. The pier was located within a body
main face in dangerous `grounds'; grouting off water of serpentine rock at a depth of 100 ft below the
ahead of face; and using gunite techniques on fresh channel surface (Fig. 7). The consulting geologists
exposures (Thompson, 1966, pp. 105±107). Andrew C. Lawson (UC-Berkeley) and Allan E.
Another critical groundwater principle was learned; Sedgwich (USC-Los Angeles), after further review
a low annual precipitation in an arid region is not in 1932, concluded that the foundation, as designed,
necessarily indicative of a dry tunnel in a highly was safe and beyond question (Lutgens et al., 1934).
faulted terrain. The water drained from the numerous Although this argument was temporarily dropped,
faults cross-cut by the tunnel depleted the ground the opposition took a different tack. They chal-
water supply to surface springs and wells. An assess- lenged the legality of the Bridge District to ®nance
ment of the damage to local ground-water supplies construction based on plans for marketing bonds at
was further complicated because no systematic data- a 5.25% rate of interest, when district approval was
base on the ¯ow of springs and wells was made before only at a 5% rate. This maneuver was defeated
construction. This resulted in costly litigation for when A.P. Giannini, Chairman of the Bank of

16
Fig. 7. The south pier of Golden Gate Bridge, San Francisco, was the focus of a geological controversy in 1930s to redesign its foundation. A contention that faults occurred in a
poor-quality serpentine foundation rock led geologist Bailey Willis to challenge ®ndings of the consulting geologists A.C. Lawsen and A.E. Sedgwich. The differences of
interpretation are shown on subsurface sections of the south pier (from Kiersch, 1991, p. 35).

Fig. 8. Geologic map of south pier area and subsurface section showing location of `faults' believed by Bailey Willis to occur and endanger the integrity of south pier foundation
(from Kiersch, 1991, p. 36).

17


America (originally Bank of Italy) pledged his 3. Growth of engineering geology-practice
bank's support Ð and quickly sold $3 million
worth of district bonds at 5%. New bids were 3.1. Overview
tendered on 14 October 1932, and construction
began on 5 January 1933. The advent of World War II (1939±1945) brought
As construction progressed into 1934, safety of about the proliferation of applied geology on a scale
the South Pier became the opposition's sole hitherto unimagined. Among the many new phases,
argument for delaying the bridge. Bailey Willis, the applications of geology to military operations as
professor emeritus at Stanford University, began a developed in Europe and South Paci®c were among
concerted drive to discredit the consulting geolo- the most important advancements in engineering
gist's interpretation of geologic conditions surround- geology of the mid-century (Kiersch, 1955, 1998).
ing the pier's foundation (Fig. 8). Willis submitted Additionally, applications of marine geology and
his ®rst report on 7 April 1934, to the Bridge District sedimentation principles were developed for naval
and later sent a report to Chief Engineer J.B. Strauss operations, such as, the use of underwater sound,
on 22 August 1934. He recommended that construc- marine mining, installation of underwater equipment,
tion be stopped until his geologic contentions were shore installations, and amphibious operations
clari®ed. Additionally, on 19 October 1934, Willis (Russell, 1950). Aerial-detection and geophysical
(1934) published a two-page discussion and his techniques developed for naval and army warfare
technical points with diagrams and a model of the have been modi®ed and successfully adapted for a
site. He contended the serpentine foundation rock wide range of geological-geophysical exploration
was an inadequate and treacherous material that purposes (Bates et al, 1982; Kiersch, 1998). Trask
would swell and decompose and large-scale fault (1950) reviewed the importance of soft rock and sedi-
movement would occur along the faults (as no. 3, ments in the major areas of geological practice, for
Fig. 8). Again Willis requested the district to stop civil and military works.
construction and redesign the South Pier of the The post-World War II period witnessed the growth
bridge; his solution was a foundation on the `sand- of applied geosciences and a substantial improvement
stone mass' at a depth of some 250 ft beneath the in the professional status of engineering geology
`as-constructed' level (shown Figs. 7 and 8). This practice. The greatly increased demand for geologists
proposal would greatly increase construction costs. to plan and participate in the construction of the major
After an extensive hearing in which each argu- engineering works approached the number of applied
ment by Willis `was carefully scrutinized and geologists participating in the discovery and exploita-
found erroneous as to fact or inference,' the Building tion of mineral resources in western states. This was a
Committee concluded: a `sandstone mass' did not dramatic change in practice for the Geoscience
occur at depth nor did a fault plane beneath the community (Betz, 1984, p. 241). These changing
pier site (Fig. 8), and furthermore, the serpentinized demands required a modi®cation of emphasis for
rock mass was a competent body, when con®ned, to professional practice of engineering geologists. The
carry the static load imposed by the bridge. The new concerns were more focused on the scienti®c
Building Committee recommended the directors aspects that included: the natural physical processes;
disregard the arguments and recommendations of dating of tectonic and associated events; reaction of
Professor Willis on 27 November 1934 (Lutgens et the environs to operating works and man-induced
al., 1934, p. 16). The long, sometimes bitter, and actions; and the geologist's responsibilities to protect
costly battle over geological arguments/concerns the health, safety, and welfare of the public (Kiersch,
that the Golden Gate Bridge design was unsafe was 1955, 1991).
closed. The bridge was open to vehicular traf®c on After World War II state agencies became more
27 May 1937; the construction costs and bond were active in addressing a wide range of engineering
fully repaid on 1 July 1971 and over time no stability geology problems, particularly in connection with
problems have been experienced in spite of several highways, water supply, urban zoning, ¯ood plains
strong earthquakes. and conservation measures. Typical of the trend was


the planning and development of statewide water
projects by the California Division of Water
Resources under the chief geologist E.C. Marliave
in the 1950s and L.B. James in the 1960s and 1970s
when more than 100 geologists were engaged with the
many phases of the California State Water Project.
Oroville dam and power facility on the Feather
River, a key installation of State Water Project,
supplies the California Aqueduct that moves water
southward to the Los Angeles area and the Mojave
high-desert east-branch to the San Bernadino region.
The aqueduct alignment crosses an extensive region
underlain by hydrocompactable soils/sediments in the
San Joaquin Valley. Areal land subsidence became a
serious geologic problem/risk due to both (a) heavy
groundwater withdrawal at depth; and (b) collapse of
the low-density near-surface deposits when saturated.
This high-risk, probability was eliminated by using
ponds along the alignment to presubside and stablize
the canal foundation (James, 1991; Borchers, 1998).
The land subsidence phenomena are also common in
parts of Arizona, Nevada, and Utah.
Concurrently, the California Division of Mines and
Geology under Ian Campbell (1958±1969) initiated
geologic mapping that de®ned the surface features
and the potential geo-risk of active processes during
a period that witnessed a burgeoning of concerns for Fig. 9. San Francisco Bay Bridge, Oakland East Bay span showing
the environmental and engineering applications of the the failed section caused by the Loma Prieta earthquake of 17 Octo-
ber 1989 (photo courtesy US Geological Survey/H. Wilshire, in
geosciences (Oakschott, 1985, p. 332). This attention Kiersch, 1991, p. 59).
to practical geologic concerns has continued since the
1970s under the current chief of CDMG, James F.
Davis. cities after the Loma Prieta earthquake of 17 October
Employment of engineering geologists by the 1989, damaged and closed the Bay Bridge (Fig. 9).
1960s was mainly in one of the two categories: on a Subsequently, Caltrans embarked on a statewide
large-scale focus related to regional/areal features and seismic retro®t program and by 1997 concluded that
how they might impact the planning-construction of the East Span of Bay Bridge, Yerba Buena Island to
engineered works; or on a detailed scale, con®ned to Oakland mole, should be replaced. Geologic investi-
small areas and site-speci®c geology that included the gations were undertaken in 1998 and planning has
construction of works. progressed for the replacement structure SFOBB
Underground rapid transit systems were being East Span project (McNeilan et al., 1998).
installed or planned in a number of cities throughout Since the World War II, airport programs have
the States by 1960; most projects required large-scale created demands for larger sites with greater bearing
geological investigations for the planning-design with capacities that created enormously expanded
an on-going input during construction. The Bay Area construction-material needs. Creating similar
Rapid Transit (BART) was built in 1966±1973 demands have been the expansion of state and federal
(Taylor and Conwell, 1981). The BART tube to the conservation measures, urban developments, reclaim-
East Bay region beneath the San Francisco Bay ing marginal lands, and military planning involving
became the only direct connection between the area air, land, and underwater applications of geology. In


the 1960s, demands required the active participation were disposal and deep burial of nuclear waste,
of applied geologists in lunar and planetary explora- disposal of garbage and refuse in land®lls, the health
tion (Green, 1962). concerns of trace elements and contaminating in
The deterioration of highways during World War II ground-water supplies, and the safety of ¯ood plains
emphasized the realization they are defense lines which and ¯ood-hazard zoning of these lands. Two new
caused highway construction to dramatically expand areas of specialized practice emerged: the identi®ca-
with improved design standards. Freeways and inter- tion and mitigation of `geologic risks' (Fig. 10)
state highways became the trend, and by design spurred by safety concerns and notable failures of
required a greater use of geologic guidance for planning large-scale engineered works; and the disposal of
and construction. In 1955, the US Congress supported a waste and deep burial projects that focused on ground
far-sighted nationwide interstate highway system for water as a contaminant carrier.
construction over a 10-year period. This activity
engaged a large group of applied highway geologists
throughout the western states in state and local agencies 4. Some representative major projects Ð since
and private consulting and engineering ®rms. 1948
Eight major dams failed around the world between
1959 and 1964. Two reservoir±dam failures in 1963, 4.1. Underground protective construction
Vaiont, Italy (Kiersch, 1964, 1988), and Baldwin
Hills, California, (James, 1968), coming after the Realization of the destructive force of the atomic
earlier failure at Malpasset, France in 1958, initiated bomb in 1945, and later the hydrogen bomb, created
a period of reconsideration and evaluation of dam concern that defense against their effects was nearly
safety. This led to mandatory inspections of dams impossible. In response, the US Corps of Engineers
and reservoirs by the 1970s and frequently such and government-sponsored research groups made
modi®cations as improving the stability of reservoir tremendous strides in the design of protective
slopes (James and Kiersch, 1988). The need for construction to resist large-scale blasts. This approach
increased electrical generating capacity could not be relied on knowledge of the geologic environs and
met by more hydro-projects and contributed to the properties of rock masses. Developments in destruc-
large-scale planning and construction of nuclear tive weapons dictated some underground locations for
power plants. military command centers and storage facilities; two
By the late 1960s, concern was building for strategic installations were built by the 1960s, the
protection of the natural environment and the impact Omaha, Nebraska, Command Control Center and
of proposed or operating engineered works. The 1969 the NORAD Center in Cheyenne Mountain near
leakage of an operating oil well in Santa Barbara Colorado Springs, Colorado. Geologic principles
Channel, California focused nationwide attention on relevant to the location, construction, and operation
the spill and led to enactment of many federal laws of subterranean installations to resist modest-scale
and regulations such as the National Environment subsurface explosions were reviewed by Kiersch
Policy Acts (NEPA) of 1969, the US Environmental (1949, 1951) and O'Sullivan, (1961).
Protection Agency (USEPA) of 1970, and the Water The underground Explosion Test Program of US
Quality Improvement Act of 1970. Many other Corps of Engineers with engineers, geologists, and
national, state, and local regulations followed in the technical staff of Sacramento District performed
1970s and 1980s and overall become the major ®eld studies at sites in Utah and Colorado. Under-
guidelines for the practice of applied geosciences ground chambers were constructed at various depths
relevant to the environment. Speci®c projects in sandstone and granite followed by live-detonations
expected to have a serious environmental impact to test scale models (1947±1950). Further research by

Fig. 10. The common natural geologic-hydrologic phenomena/geo-risks; man-induced phenomena/geo-risks; and natural atmospheric-hydro-
logic phenomena/hazards (from Kiersch, 1991, p. 55).


Engineering Research Associates (ERA), Minneapolis evaluating the expected rock and soil-overburden condi-
(1952±1953) emphasized the principal geologic factors tions along the urbanized, built-over tunnel alignment
that impact on the design of a large-scale underground (Cooney, 1952). The consultant's feasibility study
protective chamber (ERA, 1952a,b). The Rand reported the occurrence of many small faults, some
Corporation sponsored an underground construction breccia and shear zones, and considerable deformation
symposium (1959) that recorded the `state of knowl- of the Franciscan rock mass. Unfortunately, the full
edge' on the design and construction of underground geological implications and meaning of the boring
protective chambers (USCE, 1961). data, both physical and `fugitive,' were not realized
and the in-place rock conditions were incorrectly
4.2. Broadway tunnel, San Francisco, 1945±1952 interpreted (Forbes, 1945). Evaluation of the low-core
recovery (under 50%) was erroneously attributed to
The Broadway tunnel project under the historic some natural fracturing but mainly excessive mechan-
Russian Hill area was approved in 1946 and ical grinding, blocking, and overruns by the driller.
Morrison±Knudsen Company began construction in Insuf®cient attention was paid to the highly fractured
May 1950. The tunnel consists of two bores, 28.5 ft conditions of the recovered core as an indication of
wide and 35 ft apart, to provide a traf®c artery from rock-in-place. Forbes' (1945; 1951) description of the
downtown San Francisco to the northwestern part of expected rock conditions in¯uenced the contractor to
the city and the Golden Gate Bridge (Fig. 11). bid his costs on a full-face mining method.
The city of San Francisco had previously engaged a Tunneling quickly revealed a more extensively
consulting engineer/geologist in 1944 (Hyde Forbes) fractured and less-healed rock mass than expected,
to supervise the drilling of cored-borings to tunnel-grade and deterioration of rock by weathering was serious
and interpret/evaluate the site area and geological and widespread. Surprisingly, the consultant had not
exploration data for planning-design and bid-contract studied the surface outcrops near the tunnel alignment
purposes. Subsurface investigations were critical to as an aid in evaluating the characteristics of the

Fig. 11. Broadway Tunnel alignment through Russian Hill provides a low-level traf®c artery from downtown San Francisco to Golden Gate
Bridge. Note Ð location coincides with topographic saddle between Nob and Russia Hill (from Wadsworth, 1953).


Fig. 12. Broadway Tunnel, San Francisco. Geologic cross section of station 18 1 08 of the southbound lane. The typical conditions encountered
in the Franciscan rock complex are represented, along with a plot of faulted and sheared rock units and mining methods (after ®eld notes M.G.
Bonilla, 1952; US Geological Survey Library, in Kiersch, 1991, p. 53).

sandstone and shale units at tunnel-level (Marliave, contractor from the bid documents, and Chester
1951), a serious error of geological judgment. The Marliave was engaged by contractor to make a geolo-
alignment largely coincides with the topographic gical investigation. By mid-1951 the city of San
saddle between Nob and Russian Hills (Fig. 11), Francisco was also concerned and sponsored two
which commonly indicates faulting in Franciscan separate studies; one by consultant John P. Buwalda
bedrock. Moreover, the east portal area of Russian of Caltech (1951), and the other by consultant Karl
Hill was inadequately investigated; instead of Terzaghi of Boston. In addition, the as-encountered
bedrock, the area was an old, back-®lled stream geologic conditions throughout the tunnel were
channel with no bedrock. This condition required mapped by US Geological Survey personnel (M.G.
use of costly Type-A steel supports. Bonilla and co-workers). All three consultants and
As the tunnel progressed, geologic conditions the USGS investigators concluded that the geologic
continued to be very different than expected by the setting of the tunnel site had not been fully evaluated


nor adequately correlated with the cored-boring data the rock mass from mechanical ¯aws created by drilling
for either the design or bidding purposes. operations. Such ability is largely a matter of good
judgment by an experienced applied geologist.
4.2.1. Changed conditions
The Broadway tunnel project became the center of
4.3. Folsom dam, 1948±1956
a long public controversy between the contractor and
the city during 1951 and the `as-is' rock conditions. The multi-purpose Folsom dam and reservoir
The contractor contended the original consulting project east of Sacramento, utilized geologic guidance
report of 1945 was misleading, and substantially for the site selection, planning-design and construc-
changed conditions were encountered because the tion phases. The 4.8 miles of dams consist of a high
bid documents stated or implied there were: (1) no concrete gravity dam with earthen wing embankments
bedding planes in sandstone unit, no faults occur on the American River and nine saddle dams on small
parallel to tunnel alignment, and all faults healed tributaries. The Mormon Island auxiliary earth®ll dam
with rock mass generally intact; (2) no slickenside was built across the ancestral Blue Ravine channel of
features or swelling noted in the cores (implied for South Fork American River.
mass), and no indication of swelling ground; (3) no The main dam and most saddle embankments are
air-slaking materials known from cores and shales of founded on extensively fractured/sheared and
limited extent; and (4) no ground-water in¯ow is weathered quartz diorite; on-site `outcrops' were
expected. usually residual weathered boulders underlain by
The contractor was convinced that a top-heading erratic depths of highly weathered rock. The stages
or a full-face tunneling method as planned was of weathering Ð slight, moderate, highly Ð were
impractical. The rock mass varied from hard to established by their respective petrographic and
soft, the highly weathered, sheared, and fractured physical properties. This classi®cation strengthened
rocks air-slaked on exposure, and large slabs the geologist's ability to estimate depths to suitable
could be air-spaded or chipped off easily, and blast- foundation rock. Conventional subsurface explora-
ing was controlled and used sparingly. tion techniques investigated the main dam with
Consequently, the contractor changed mining cored-borings, geophysical surveys, bore hole
methods to the plumb-post method (Cooney, 1952) camera photography, down-hole logging of man-
after driving the north bore 178 ft from the east portal. sized openings, and 48-in. auger/calyx holes.
Mining progressed from two header foot-block drifts Foundation excavation for the main dam
9 ft wide on each side at the base of the tunnel section progressed in three separate contract stages, based
(Fig. 12). The remaining 60% of the face excavation on the design investigations. Extensively weathered
were removed with a breast-board machine. A design rock at each successive excavation-level veri®ed the
controversy immediately arose because the contractor limitations of small-diameter cored boring data to
had originally recommended the stronger Type-B (full clarify the complexity of a weathered rock mass.
circle) tunnel support in sectors of the tunnels with Additional exploration was required prior to the
soft-weak rock conditions but the city rejected this second and third stages of excavation, by shallow
proposed change in design. percussion drill holes, shafts, adits, and man-sized
holes. The degree and extent of weathered rock at
4.2.2. Overview excavation-levels are shown on three-dimensional
The Broadway tunnel experience emphasizes the diagrams as are faults delineated in foundation rock
importance of an accurate interpretation of drill core and zones requiring dental treatment (Fig. 13).
data, and the ability to distinguish geologic defects in Core trenches of earth®ll and saddle embankments

Fig. 13. Three-stage block diagram of excavation, right abutment (west) Folsom dam that illustrates the diverse weathering characteristics of
foundation rock and associated geologic features. Conditions exposed at each level aided in predicting the extent and type of weathered rock at
subsequent levels and the ®nal foundation elevation (Kiersch and Treasher, 1955).


were grouted on a split-method pattern. Grouting the within the 40-mile strip were mapped for geologic
permeable, highly weathered quartz diorite was trends and features that could project onto or impact
dif®cult due to the abundance of clayey-®lled SPCo holdings. The alternate odd-numbered sections
fractures. Impervious earth®ll was `borrowed' from of Southern Paci®c's land-grant holdings, were 38%
areas of highly weathered quartz diorite; permeable of the area investigated (Kiersch, 1958, 1959; Fig. 5).
®ll was supplied from alluvium deposits. Full details The geological survey utilized all the principles and
on Folsom project are given elsewhere by Kiersch and geological techniques available in the 1950s and
Treasher (1955, pp. 271±310). followed the broad steps outlined in Stages 1±6
The powerhouse was placed in a deep excavation (Fig. 14). Parts of the survey mapping were incorpo-
250 ft below the river channel for additional power rated into the 1959±1969 edition of the Geologic
head. The Mormon Island auxiliary dam is founded Atlas and Map of California (Jennings, 1969) and
on metamorphic rocks that underlie the auriferous an early edition of the Geologic Map of Nevada
gravels of Blue Ravine Channel. The Folsom project (Webb and Wilson, 1962).
was constructed prior to knowledge of any seismic The large-scale geologic mapping combined with a
history in region. Since, the State of California has systematic inventory of known or potential resources
re-evaluated and declared the project susceptible served a host of uses for new construction, mainte-
to seismic activity (Sherburne and Hauge, 1975). nance of engineered works, the railroads trackway,
Consequently the Mormon Island dam received land management, and a means of attracting new
remedial upgrading treatment in 1990s by the US industry and developments for rail service. Resources
Corps of Engineers. data on minerals, fuels, water, soils, or engineering
materials became an asset, whether for maintaining
4.4. Geological mapping SPCo lands Ð related the railroad trackways in dif®cult and slide-prone
engineered works, 1955±1961 terrain, or providing additional freight and/or lease
revenue from untapped deposits. `Nonmineral' lands
The most ambitious private geological mapping were managed exclusively for their surface value or
project of its day was completed between 1955 and ground-water without concern for possible future
1961 by the Southern Paci®c Corporation (SPCo), a mineral leasing. This approach provided a suitable
geological survey and evaluation of its landholdings understanding of geologic conditions and their rele-
in California, Nevada, and Utah (earlier studies 1909± vance to agriculture, grazing, timber, recreation, and
1925; Fig. 5). The broad-based geologic mapping and commercial plant sites, as well as guidance for litiga-
related special projects were designed to provide tion and claims ®led against SPCo. The geological
technical guidance and a comprehensive database database was also utilized to select new sites for
to manage the SPCo lands for the ensuing 50-year major industrial developments and provide guidance
period. The SPCo Board of Directors authorized a on geological problems arising from operation of the
geological survey with exploration and evaluation railroad system and the SPCo oil-supply pipeline,
of company lands in 1954 for guidance in their such as, mitigation of slides, earthquake damage,
management as well as assistance to the industrial and tunnel failures. The Alta landslide is one such
and resources departments and related SPCo engi- use of the survey's database.
neering projects of railroad and pipelines.
The survey was operating at full strength by late 4.4.1. Alta landslide, trans-continental railroad
1955 and consisted of ®ve regional/areal mapping The major slope failure and debris slide of April 1958
crews in ®eld plus supporting researchers and of®ce near Baxter, California, blocked the main west-east
staff of professionals along with a separate special- transcontinental railroad and temporarily closed US
projects staff that investigated prospects and resource Highway 40. The ®nancial losses sustained by SPCo
development in the follow-up phase. Some 22,000 approached $1 million/day. Geological data collected
miles, the equivalent of 93, 15 min quadrangles, earlier by the SPCo survey from nearby lands provided
were mapped (scale of 1:24,000) on standardized a knowledge of ground-water conditions and physical
SPCo-prepared two-township base maps. All lands properties of the unstable tuffaceous Tertiary rock units

Fig. 14. Flow chart for the regional/areal approach to geoscience investigations for site selection and design of engineered works (from Kiersch, 1958, 1964).

27


Fig. 15. (A) Alta slide of 14 April 1958. Looking westward along outer track that was undercut and destroyed by caving. Note: Toe of slope
intact; area later impacted by the surcharge of waste debris removed for track widening. Shows steep cliff of case-hardened tuff beds with
contact between rock units near track-level. For downhill extension of total slide area see (B); pilings indicated area of original caving/sliding
(source: Kiersch 4-14-58, 1962). (B) Alta slide California Ð looking uphill from future I-80 Highway alignment in October 1959 after the cut
in tuff beds above railroad grade was benched and stabilized. Note: pilings for marker shown Fig. 15-A and the original small-slide that
subsequently spread down slope and triggered large-scale movement. Recent ®ll in foreground shows extensive movement that impacted US
Highway-40 immediately downhill. Stabilization required deep drains located in the underlying Tertiary gravels. The slide mass of low-shear
strength was saturated 30±40 ft below the surface and monitored by a network of borings and water-¯ow test holes (source: Kiersch 10-14-59, 1962).

that caused the trackway collapse, and the subsurface of ®nancial loss. Long-term stabilization was
conditions downslope from the railroad that affected achieved only after an extensive geologic investiga-
and temporarily closed Highway 40 (Fig. 15A and B). tion of the site in the fall of 1959 outlined the total
Fortunately, the immediate cause of failure was slide mass. This effort included obtaining cored-
temporarily mitigated within four days and the main boring data, installing horizontal drains along hillside
line returned to one-way traf®c, which avoided some of trackway, and evaluating a joint effort for long-time


stability of the slide with the California Department of embankment. Consequently, the às-built' causeway
Highway. This led to construction of an extensive became the `test section,' which was closely moni-
drain-system downslope of the SPCo trackway tored and modi®ed according to the às-encountered'
(Fig. 16) to stabilize the area for construction of foundation units. This resulted in successful comple-
the I-80 freeway that replaced the damaged Highway 40 tion of the project one year ahead of schedule
(Kiersch, 1962, pp. 135±144). (Casagrande, 1965). Success would not have been
achieved however, if the consultants had known
4.4.2. Railroad causeway Ð SPCo, Great Salt Lake, before construction the às-is' strength of the Glauber's
Utah salt and clay beds would control the stability of the
An outstanding example of a calculated risk is the embankment. Moreover, Southern Paci®c probably
design and construction of a Southern Paci®c railroad would not have authorized the project. Based on the
embankment across the Great Salt Lake to replace the às-built' knowledge of the foundation units, the
12-mile-long timber trestle that was built at the conventional factor of safety required would have
beginning of this century (inset, Fig. 17). The new forced a design ®ll costing far in excess of the 1955
®ll, which was built during 1956±1959, started from estimate and $50 million limit established by the
the old ®ll sections and ran parallel to the trestle, Board of Directors of Southern Paci®c Corporation.
located 1500 ft to the north. This ensured that Although the initial misinterpretation of subsurface
construction of the ®ll would not endanger the trestle units and their inherent strengths allowed the project
(Casagrande, 1965). to get underway, the adoption of ®eld test data and
Preconstruction laboratory strength tests on undis- evaluation of the risk as construction progressed
turbed samples of the soft and sensitive silty clay and resulted in its successful completion.
Glauber's salt units, which underlie the lake to a great A ®ll built on normally consolidated clay has its
depth (Fig. 17) and the foundation for the causeway, lowest factor of safety against foundation failure
indicated the design would involve great uncertainties. during construction or immediately after its comple-
The Glauber's salt varies greatly in thickness and tion. Since the new railroad causeway was put in
strength and underlies the ®ll for many miles, with operation (1959) the rate of settlement has gradually
its upper surface at a depth of 20±30 ft below lake decreased in a consistent pattern that re¯ects a
bottom. This seriously complicated the design and steadily increasing strength of the clay.
construction of the ®ll (Fig. 17); several design stages The Great Salt Lake causeway project is a good
for the cross section on soft clay (no salt layer) are example of what Karl Terzaghi liked to call the
given by Casagrande (1965). òbservational approach,' i.e. the continuous evaluation
To achieve an economical design it became neces- of observations and new information for redesigning
sary to build full-scale test ®lls and induce failures; as needed while construction is in progress. It also
these ®eld tests developed data on the in situ strength illustrates Terzaghi's belief à design is not completed
of the foundation units. Particularly impressive were until the construction is successfully completed'
the failures of ®ll founded on the Glauber's salt layer (Casagrande, 1965).
(Fig. 17). For practical purposes the salt had to carry The calculated risks involved in this project would
the entire lateral thrust of the ®ll. When the salt not be complete without mentioning another risk. The
buckled, the ®ll sank into the soft clay with extra- `sand and gravel' used for the main body of the under-
ordinary speed. Even the most pessimistic initial water ®ll was largely a silty sand. The question of its
assumptions of the consultants did not prepare them stability under dynamic stresses was of serious
for the very low in situ strength of the soft clay, gained concern to the consultants and a calculated risk
from the analysis of the test section failures and other which could have defeated the design and ultimate
®ll sections. Although the consulting board ®rst construction.
recommended construction of full-scale test sections
for design data, they soon learned that a test ®ll could 4.5. Auburn Dam controversy, 1948±1979
be built only by mobilizing most of the expensive
equipment needed for construction of the entire Major geological and geotechnical investigations


were carried out in the 1950s±1970s in support of the project design. Ultimately the controversies led to a
design and construction of the authorized Auburn `deferral' of the proposed dam at the 1948 site. Public
Dam at a site on the North Fork of American River, interest in a dam on the North Fork has continued;
upstream of Folsom project. This long and expensive other nearby sites and dam designs have been
controversy is a classic case of `differing professional proposed, particularly after ¯oods caused damage
opinions' concerning the safety and design-costs of to urban areas downstream (after Shlemon, 1999
`the world's largest thin-arch, double-curvature high (written communication)).
dam' proposed east of Sacramento, California. Despite the strong diversity of technical opinion,
Authorized in 1948, the US Bureau of Reclamation the Auburn controversy provided valuable bene®ts
(USBR) spent years and millions of dollars conduct- to the engineering±geology community, even though
ing technical and scienti®c investigations to support the investigations and arguments took place when
the dam's construction and operation (Gardner et al., environmental concerns were increasing in popularity;
1957). Yet the ®ndings of the USBR's investigations, perhaps the dam was a `victim' of the 1970s trend.
interpretation of the data, and conclusions became The various types of investigations and techniques
questionable, when evaluated by other experienced used to ascertain the relative activity of faults at the
technical groups, after the Oroville earthquake of damsite substantially improved the local geologic and
August 1975. This event ruptured the ground surface geotechnical standard-of-practice (Shlemon et al.,
of the Cleveland Hill fault, a strand of the Sierra 1992).
Nevada Foothills fault system, and con®rmed the
region was more seismically active than previously
believed (Sherburne and Hauge, 1975). Subsequently, 4.6. Nuclear power plants
additional site-speci®c and regional investigations
were carried out by the USBR, other governmental Increasing electricity demands triggered the plan-
agencies, and respected consulting ®rms (Borcherdt ning for construction of nuclear power plants in late
et al., 1975; USBR, 1977, 1978; Woodward-Clyde, 1950s. Each plant design required seismotectonic
1977). They collectively expressed concern that investigations to establish the recent last movement
faults, known within the foundation area, are poten- on fault zones within the region/area. This Federal
tially `active' and the dam had to be re-designed to requirement advanced the scienti®c techniques/
withstand the ground displacement of an active fault methods for dating tectonic events that included a
(Davis et al., 1979). sequential history of multiple alluvial units, dating
The diverse and strong differences of opinion the associated minerals, and a correlation with
concerning the Auburn damsite features were based tectonic and geomorphologic features. Soil science
on geological data gained from subsurface-trench techniques proved basic to dating Quaternary sedi-
exposures of datable sediments overlying bedrock ments (Shlemon, 1985), and classi®cation of fault
faults, either displaced or unbroken (Shlemon, zones as active, potentially active, and/or dormant.
1985). Separate agencies or consultants emplaced In early years the associated geologic features/
trenches side-by-side, yet often arrived at different processes were seemingly not as critical than in later
conclusions. The myriad of trenches at and near the years to the designers, constructors, and regulatory
damsite resembled a World War I battle®eld. Tech- agencies. Early geological investigations for plant
nical controversy abounded concerning the `safety' of sites (1950s±1960s) pioneered the licensing proce-
project and hearings were conducted before various dures and ultimate technical requirements leading to
regulatory agencies, both for and against the site and termination or delay of four California projects,

Fig. 16. Plan View Ð corrective measures that stabilized `lower' Alta slide involving the Interstate I-80 alignment. Lowering water table
required 30 in. diameter wells installed on 8 ft centers between the highway and railroad alignment and shown as drainage galleries. The wells
are inter-connected at the bottom and the galleries are joined to the transverse stabilization trenches which are spaced on 8 ft centers and are
30 ft deep and 12 ft wide at bottom with 1 1/4:1 side slopes (modi®ed after Cauley, 1962).

32
Fig. 17. Southern Paci®c Railroad, Great Salt Lake causeway. Embankment construction and the reaction of subsurface geologic units, particularly near-surface bed of Glauber's
salt. The section shows typical exploration holes and the composition of the lake beds to depths of more than 200 ft at Lucin, Utah (after Haley and Aldrich Co., personal
communication; Currey and Lambrechts, personal communications; Kiersch, 1991, p. 552).

Development of engineering geology in western united states

Development of engineering geology in western united states

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