excavation equipments, types with advantages and limitations

1. LD COLLEGE OF ENGINEERING
Sub :- Advanced Construction &
Equipments
Topic :- Excavating Equipments
Prepared By :- Makwana Tulsi 130280106052

2. Excavating Equipments :
excavation + equipments
The act of digging An instrumentality
needed for an
undertaking or to
perform a service

3. Types of excavating equipments:-

4. POWER SHOVELS:-
 Primarily used to excavate and load into
hauling vehicles.
 Size,indicated by size of dipper(in 𝑚3).
sizes
3
8
,
1
2
,
3
4
, 1,1.25,1.5,2,2.5 𝑚3
 Bank measure volume. 4𝑚3 less
than loose vol. of soil. 5𝑚3
The reason is swelling.(25%)
 Applications :
 For excavating above its own track.
 Heavy cutting and loading in all types of soil.

5. Basic parts:
Hoist line
Boom
axis of rotation
Bucket
Cab
Crawler
mounting

6. Types of power shovel:
 Crawler mounted.
Low travel speed.On soft grounds.
 Wheel mounted.
High speed.On hard ground.
Conditions for operation:
 Large open pit , floor must be well drained , haul road must be well.
 Angle of swing 90°.
 Optimum depth.

7. Output / production(𝑚3/hr):
 Output =
𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑒𝑥𝑐𝑎𝑣𝑎𝑡𝑒𝑑 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙
𝑇𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 ℎ𝑟𝑠 ∗ 𝑁𝑜. 𝑜𝑓 𝑐𝑦𝑐𝑙𝑒𝑠/ℎ𝑟
 Production cycle:
 Factors affecting output :
Class of material Job conditions
Height of cut. Size of hauling units
Angle of swing Haul unit exchange
Management conditions Operator’s skill
Load bucket Swing with load Dump load Return
7 - 9 secs 4 – 6 secs 2 – 4 secs 4 – 5 secs

8. DRAGLINES :
 Named : Its prominent operation of
dragging the bucket against the
material to be dug.
 Capacity – Size of the bucket (𝑚3).
 Applications :
 Digging softer material & below
its tracks.
 It has long reaches.
 Mostly used in excavation of
canals and depositing on
embankment without hauling
equipments.

9. Basic parts :
Hoist cable Hoisting cable
Crane boom Gantry
Hoist
Chain
Drag Cable Cab
Drag Chain Crawler
Bucket Mounting

10. Factors affecting the output:
 Size and type of bucket (0.38 to 3.06 𝑚3)
Light bucket – loose,dry.
Medium – clays,compacted gravel.
Heavy – hard materials
 Length of crane boom (50,60 and 70 ft)
 Type of material
 Angle of swing
 Depth of cut
 Working conditions,maintainance
 Size of hauling unit
 Operator skill

11. Types of draglines :
 Crawler mounted
- Low travel speed,soft ground,
large projects
 Wheel mounted
- high travel speed,firm ground &
scattered job
 Truck mounted
- high travel speed,firm ground &
scattered jobs
 Walking draglines

12. Output :
 Output = dragline capacity × C × F
where C = cycles/hr
F = correcting factor
Advantages Disadvantages
 Can work from the ground surface
while shovel has to be taken into
the pit.
 Hauling equipments need not to go
in the pit.
 Excavated material disposed in one
operation.
 High range than shovel.
 Less digging force.
 As the boom length increases the
bucket size must be decreased.
 Output is less than shovel.

13. HOES :
 Machine of power shovel group.
 Used generally to excavate below the natural surface resting on.
Parts :
Bucket
cylinder
stick cylinder cab
boom
dipper cylinder
stick
Bucket boom
(dipper)

14. Applications :
 Though not efficient as shovel.
 Most suitable for digging below the machine level.
 Levelling and loading.
 Used to trim the surface.
Points for Selection of hoe :
 Maximum Excavation depth.
 Maximum Working radius.
 Maximum dumping height.
 Hoisting capability.

15. Factors affecting output :
 Excavation depth.
 Most affective digging when boom stick is
at 90 to boom.
 Max. output when excavation near machine.
 Optimum depth.(50 to 60% of max digging depth)
Advantages Disadvantages
 Hoe exert greater tooth pressure than
shovel due to direct pull.
 Due to rigidity superior than draglines.
 Superior to trenching machines when
the side banks are allowed to have
natural slope.
 Not efficient as shovels.
 Slow in working when dumping in
hauling machines.
 Liable to fall.

16. CLAM SHELLS :
 The name the machine is derived from
the shape of its bucket.
 The shape of bucket is that of the shell
hinged at the top which can be closed
and opened in two parts.
 Selection depends largely on the
requirement of the job.
Crane
Clam shell
Bucket cabin

17. Bucket :
 Consists of two shells with hinged at the
top and provided with sharp edges at the
bottom.
 Heavy types of buckets with sharp cutting
edges are used for hard soils and light
buckets with plane edges for loose soil.
 Used mostly in lifting the heavy rock
pieces.
 Sometimes more than two jaws are used
for lifting large sized particles.
Shell Shell
Hinge
Hoist line
Sheaves
brackets

18. Effective use :
 Unit must be on level ground.
 Bucket teeth should be sharp.
 Dumping distance = digging distance.
 In soft soils teeth should be removed.
Output/production of clam shell :
 Production = capacity(𝑚3
) × C × F
C = cycles/hr
F = correction factor

19. Factors affecting the output :
 Height of lift.
 Angle of swing.
 Method of disposing.
 Operator’s skill.
Applications :
 Used for loose materials such as crushed stones.
 Main function is to vertical lifting of material from one place to another.
 Digging and dumping in vertical plane.
 Accurate dumping.
 Charging and removing the materials from a stock pile,cofferdams,etc.

20. TRENCHING MACHINES :
 Excavate all type of soils except rocks.
 Mostly crawler mounted.
Applications :
 Excavating trenches for water,oil,gas
pipes,sewers & telephone cable .
 Deepening of existing drainages.
 Used where control on depth and width is required.
 Fast digging.
 Reduces the cost of hand finishing.

21. Types of trenching machines :
 Wheel type :
 Consists of power driven wheel
mounted with number of
removable buckets with teeth.
 They can cut trench of width upto
30 to 150 cm.
 Maximum cutting depth 2.5 – 3 m.
 Have greater digging speeds.
 For narrow trench in firm soil this
type is suitable.

22.  Ladder type :
 Consists of two endless chains which
travel along the boom and the buckets
equipped with teeth are attached.
 Sometimes side cutters are attach to
increase the width of the trench.
 The conveyer belt disposes the
excavated soil on the either side.
 Maximum cutting width upto 360 cm.
 Maximum cutting depth 9.0 to 10.0 m.
 Digging speed is 30 m or more.

23.  Vertical boom type :
 Modified of ladder type.
 Trench width ranges from 40 to 70 cm.
Points taken care while selecting the type :
Type of soil. Obstructions
Depth and width of the trench. Right of way for disposal of earth.
Amount of work. Topography of the area.
Water table. Climatic conditions

24. Comparison between different types of excavating
equipments :
Items Power shovel Hoe dragline Clam shell
Excavation in hard soil or
rock
Good Good Not good Poor
Excavation in wet soil or
mud.
Poor Poor Moderate Moderate
Distance between footing
and digging.
Small Small Long Long
Loading efficiency. Very good Good Moderate Precise but
slow
Footing required. Close to work Close to pit Fairly away
from pit
Fairly away
from pit
Digging level Digs at or above
footing
Digs below
footing
Below footing Digs at or
above footing
Cycle time Short Slightly more
than shovel
More than
power shovel
More than
others

25. Example : (GTU May/June 2012)
 Determine the cost of production in terms of rupees/𝑚3.
 Excavating equipment : Hoe with 1.51𝑚3
having cycle time of 16 sec and
operating factor 55 minute/hr.Cost 3500/hour.
 Material : good common earth with swell of 20% and fill factor of 0.85.
 Hauling units : trucks 8.5 𝑚3
capacity operating factor 50 minutes/hour and
having round trip time 22 mins.Cost 400/hour.
 Solution :
 Equipment type : hoe
 Bucket capacity : 1.51 𝑚3
 Cycle time : 16 sec
 Fill factor : 0.85
 Swelling : 20 % operation factor : 55 min / hour

26.  Ideal hour output:
no of cycle =
𝑡𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒
𝑡𝑖𝑚𝑒 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑓𝑜𝑟 𝑜𝑛𝑒 𝑐𝑦𝑐𝑙𝑒
=
60 ∗ 60
16
= 225 cycles
 Ideal hourly output (𝑚3) : 225 × 1.51 = 340𝑚3
 Probable hourly output = 340 × operation factor × fill factor × swell
= 340 × (50/60) × 0.85 × (1/1.20) = 220.76𝑚3
Cost 3500/hr
 Cost of excavation / 𝑚3
= 3500/220.76 = 15.85 / 𝑚3
 Hauling cost/𝑚3 :
output /hour = 8.5 × 50/22 = 19.32 𝑚3
cost Rs. 400/hr
Hauling cost/𝑚3 = 400/19.32 = Rs. 20.70/𝑚3
 Total cost of excavation and hauling = 15.85 + 20.70 = Rs. 36.55/𝒎 𝟑