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Strength of different materials
Steel Concrete Soil
Tensile strength Compressive strength Shear strength
Embankment
Strip footing
Shear failure of soils
Soils generally fail in shear
At failure, shear stress along the failure s...
Retaining
wall
Shear failure of soils
At failure, shear stress along the failure surface
(mobilized shear resistance) reac...
Other laboratory tests include,
torsional ring shear test, plane
strain triaxial test, laboratory vane
shear test, laborat...
Vane Shear Test
What does Vane Shear Test measure?
o Shear strength
A term used to describe the maximum strength of soil at which
point si...
PLAN VIEW
Vane shear test
This is one of the most versatile and widely used devices used for
investigating undrained shear...
Vane shear test
Since the test is very fast,
Unconsolidated Undrained
(UU) can be expected
T = Ms + Me + Me = Ms + 2Me
Me ...
Surface area of the cylinder = 2πrh = πdh
Vane shear test
Since the test is very fast,
Unconsolidated Undrained
(UU) can be expected
Ms – Shaft shear resistance alo...
Vane shear test
Since the test is very fast,
Unconsolidated Undrained
(UU) can be expected
T = Ms + Me + Me = Ms + 2Me
Me ...
Vane shear test
Since the test is very fast,
Unconsolidated Undrained
(UU) can be expected
T = Ms + Me + Me = Ms + 2Me
Me ...






+
=
42
32
dhd
T
Cu
βπ
Generally, We have to use this
formula for accounting
By inserting value according to
...
Vane shear test
Since the test is very fast,
Unconsolidated Undrained
(UU) can be expected
After the initial test, vane ca...
Some important facts on vane shear test
 Insertion of vane into soft clays and silts disrupts the natural soil
structure ...
Correction for the strength parameters obtained
from vane shear test
Bjerrum (1974) has shown that as the plasticity of so...
2006 –– 2007 Pre-Treatment
Phase
South Fraser Perimeter Road
Geotechnical Investigation
Data Report
South Delta (Volue 2)
...
FIELD VANE TESTING RESULTS
Small vane – 11.0cm x 5.0cm – Constant = 0.20
Medium vane – 13.0cm x 6.5cm – Constant = 0.1
Lar...
= 7.75
Small vane – 11.0cm x 5.0cm Max. Torque (T) =
22 N.m PI=60 dry=17.30 KN/m3Ɣ
Cu(design) = λCu(vane shear) = 0.74 * 2...
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
FIELD VANE TESTING RESULTS
According to FHWA Geosynthetic Design and Construction
Guidelines
(Berg, et. al., 1998)
Section No. 5.6
“subgrade undraine...
From the results of vane shear test, we summarized the following
notes:
-The major type of soil is Medium and soft (except...
- Using Geotextile Placement as solution for separating the weak
subgrade away from the sub-base, base course and other
pa...
- Refill the sub-base course by forming embankment with good
compaction according to specifications with high quality mate...
- Spreading Geogrid reinforcement sheets on the top surface of the
sub-grade and in the base course (if necessary).
Recomm...
- Protect the sloped sides of embankment with replacing of Geogrid
reinforcement sheets specially at the side of sea and p...
Applications of Vane Shear Test in Geotechnical soil investigations
Applications of Vane Shear Test in Geotechnical soil investigations
Applications of Vane Shear Test in Geotechnical soil investigations
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Applications of Vane Shear Test in Geotechnical soil investigations

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Applications of Vane Shear Test
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Applications of Vane Shear Test in Geotechnical soil investigations

  1. 1. Strength of different materials Steel Concrete Soil Tensile strength Compressive strength Shear strength
  2. 2. Embankment Strip footing Shear failure of soils Soils generally fail in shear At failure, shear stress along the failure surface (mobilized shear resistance) reaches the shear strength. Failure surface Mobilized shear resistance
  3. 3. Retaining wall Shear failure of soils At failure, shear stress along the failure surface (mobilized shear resistance) reaches the shear strength. Soils generally fail in shear Failure surface Mobilized shear resistance Retaining wall
  4. 4. Other laboratory tests include, torsional ring shear test, plane strain triaxial test, laboratory vane shear test, laboratory fall cone test Determination of shear strength parameters of soils (c, φ or c’, φ’) Laboratory tests on specimens taken from representative undisturbed samples Field tests Most common laboratory tests to determine the shear strength parameters are, 1.Direct shear test 2.Triaxial shear test 3.Vane shear test 4.Compression test 1. Vane shear test 2. Torvane 3. Pocket penetrometer 4. Fall cone 5. Pressuremeter 6. Static cone penetrometer 7. Standard penetration test
  5. 5. Vane Shear Test
  6. 6. What does Vane Shear Test measure? o Shear strength A term used to describe the maximum strength of soil at which point significant plastic deformation or yielding occurs due to an applied shear stress. o Undrained shear strength Refers to a shear condition where water does not enter or leave the cohesive soil during the shearing process. o Remolded undrained shear strength Is the peak undrained shearing resistance measured during the initial rotation of the vane. o Peak undrained shear strength Is the shear strength after significant failure and remolding of the initial soil structure. o Sensitivity Is the effect of remolding on the consistency of cohesive soil.
  7. 7. PLAN VIEW Vane shear test This is one of the most versatile and widely used devices used for investigating undrained shear strength (Cu) and sensitivity of soft clays Bore hole (diameter = DB) h > 3DB) Vane D H Applied Torque, T Vane T Rupture surface Disturbed soil Rate of rotation : 60 – 120 per minute Test can be conducted at 0.5 m vertical intervals
  8. 8. Vane shear test Since the test is very fast, Unconsolidated Undrained (UU) can be expected T = Ms + Me + Me = Ms + 2Me Me – Assuming a uniform distribution of shear strength ∫= 2 0 ).2( d ue rCrdrM π 2 0 32 0 2 3 22 d u d ue r CdrrCM       == ∫ ππ 1283 2 33 dCdC M uu e ππ =      = d/2d/2 Cu Cu Cu h
  9. 9. Surface area of the cylinder = 2πrh = πdh
  10. 10. Vane shear test Since the test is very fast, Unconsolidated Undrained (UU) can be expected Ms – Shaft shear resistance along the circumference 22 2 hd C d dhCM uus ππ == 2 122 32 ×+= dChd CT u u π π       += 62 32 dhd CT uπ       + = 62 32 dhd T Cu π T = Ms + Me + Me = Ms + 2Me Cu Cu h
  11. 11. Vane shear test Since the test is very fast, Unconsolidated Undrained (UU) can be expected T = Ms + Me + Me = Ms + 2Me Me – Assuming a triangular distribution of shear strength d/2d/2 Cu       + = 82 32 dhd T Cu π Cu Cu h
  12. 12. Vane shear test Since the test is very fast, Unconsolidated Undrained (UU) can be expected T = Ms + Me + Me = Ms + 2Me Me – Assuming a parabolic distribution of shear strength       + = 20 3 2 32 dhd T Cu π d/2d/2 CuCu Cu h
  13. 13.       + = 42 32 dhd T Cu βπ Generally, We have to use this formula for accounting By inserting value according to the shear shape. u C β
  14. 14. Vane shear test Since the test is very fast, Unconsolidated Undrained (UU) can be expected After the initial test, vane can be rapidly rotated through several revolutions until the clay become remoulded τpeak τultimate τ Shear displacement StengthUltimate StengthPeak ySensitivit = Cu Cu h
  15. 15. Some important facts on vane shear test  Insertion of vane into soft clays and silts disrupts the natural soil structure around the vane causing reduction of shear strength  The above reduction is partially regained after some time  Cu as determined by vane shear test may be a function of the rate of angular rotation of the vane
  16. 16. Correction for the strength parameters obtained from vane shear test Bjerrum (1974) has shown that as the plasticity of soils increases, Cu obtained by vane shear tests may give unsafe results for foundation design. Therefore, he proposed the following correction. Cu(design) = λCu(vane shear) Where, λ = correction factor = 1.7 – 0.54 log (PI) PI = Plasticity Index Overconsolidation Ratio:
  17. 17. 2006 –– 2007 Pre-Treatment Phase South Fraser Perimeter Road Geotechnical Investigation Data Report South Delta (Volue 2) Date: November 27, 2007 File #: 03-1411-095B/4600/4630 Version: FINAL Geotechnical Investigation Report done by using Vane Shear Test
  18. 18. FIELD VANE TESTING RESULTS Small vane – 11.0cm x 5.0cm – Constant = 0.20 Medium vane – 13.0cm x 6.5cm – Constant = 0.1 Large vane – 17.2cm x 8.0cm – Constant = 0.05
  19. 19. = 7.75 Small vane – 11.0cm x 5.0cm Max. Torque (T) = 22 N.m PI=60 dry=17.30 KN/m3Ɣ Cu(design) = λCu(vane shear) = 0.74 * 24 = 17.67 kPa OCR kPa
  20. 20. FIELD VANE TESTING RESULTS
  21. 21. FIELD VANE TESTING RESULTS
  22. 22. FIELD VANE TESTING RESULTS
  23. 23. FIELD VANE TESTING RESULTS
  24. 24. FIELD VANE TESTING RESULTS
  25. 25. FIELD VANE TESTING RESULTS
  26. 26. FIELD VANE TESTING RESULTS
  27. 27. FIELD VANE TESTING RESULTS
  28. 28. FIELD VANE TESTING RESULTS
  29. 29. FIELD VANE TESTING RESULTS
  30. 30. FIELD VANE TESTING RESULTS
  31. 31. FIELD VANE TESTING RESULTS
  32. 32. According to FHWA Geosynthetic Design and Construction Guidelines (Berg, et. al., 1998) Section No. 5.6 “subgrade undrained shear strength must be not less than about 90 kPa (CBR < 3). “
  33. 33. From the results of vane shear test, we summarized the following notes: -The major type of soil is Medium and soft (except in two results - Stiff) . -All Cu values (except AH06-308B) is less than 90 Kpa, which mean that subgrade should be treated and improved. -The project is 40 km Highway located close to the riverbank. Summarized notes:
  34. 34. - Using Geotextile Placement as solution for separating the weak subgrade away from the sub-base, base course and other pavement layers and keep it away from ground water. Recommendations:
  35. 35. - Refill the sub-base course by forming embankment with good compaction according to specifications with high quality materials the subgrade materials with other high quality materials or adding aggregate , additive to improve the quality of subgrade materials. Recommendations:
  36. 36. - Spreading Geogrid reinforcement sheets on the top surface of the sub-grade and in the base course (if necessary). Recommendations:
  37. 37. - Protect the sloped sides of embankment with replacing of Geogrid reinforcement sheets specially at the side of sea and pouring concrete slabs or placing precast concrete tiles on the outer slope. Recommendations:
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