1. The document describes a project to determine the load carrying capacity of a 600mm diameter, 23m long cast in situ concrete pile using PLAXIS 2D software. Soil properties from borehole tests and laboratory tests are input into an axisymmetric pile model. 2. Loads are applied incrementally to the pile model and settlement is recorded to generate a load-displacement curve. The ultimate load is determined as 1850kN from the curve. 3. Allowable load is calculated using code criteria and found to be 954.548kN, matching the field test value. References used for the analysis are listed.

1. PROJECT
ON
LOAD CARRYING CAPACITY OF PILE USING PLAXIS 2D
UNDER GUIDANCE
OF
DR. AMARNATH HEDGE
BY
KUMAR ANJNEYA
RESEARCH SCHOLAR , INDIAN INSTITUTE OF TECHNOLOGY PATNA

2. Q. Problem statement
Find the load carrying capacity of the cast in situ concrete pile of 600 mm diameter and length of 23 m
for the given soil profile.
PROJECT- Proposed Inter state bus terminal at patna
Bore/Drill log 2 – M.S. TEST HOUSE

3. LABORATORY TEST RESULT FOR BORE LOG-2

4. DETERMINATION OF E
Source : foundation analysis and design by Joshep E. Bowles

5. Pile properties
Linear elastic
Type of behaviour= non porous
unit weight = 24 Kn/m3
youngs modulus of elasticity = 3 x 107 kN/m2
poisson’s ratio = 0.1
Fig : bored pile
Source : http://www.ffgb.be/Business-Units/Retaining-
Walls---Utilities/Verbuisde
PILE IS CAST IN SITU PILE (BORED PILE)
Poison’s ratio

6. Laboratory test result values
Layer 1
Y(unsat) =18 KN/m3
Y(sat)= 18.06021 kN/m3
Cu= 30.411 KN/M2
E= 750 Su =22808.25KN/M2
SPT N- 11, µ= 0.4
FIG: SOIL PROFILE
Layer 2
Y(sat)= 18.31 kN/m3
Cu= 36.624 KN/M2
E= 1000 Su =36624 KN/M2
SPT N- 22 , µ= 0.4
Layer 3
Y(sat)= 18.46 kN/m3
Cu= 54.936 KN/M2
E= 1500 Su =82404 KN/M2
SPT N- 39 , µ= 0.45
Water table
7.50 m

7. GETTING STARTED WITH
Axisymmetric element :15 noded element
Soil profile
Material properties
Assigning the values

8. Making pile through soil polygon tab and adding interfaceAssigning the load udl
Continued……

9. Water table assigning
Assigning the load value

10. BOUNDARY CONDITIONS
x min = normally fixed
X max = normally fixed
Y max= fully fixed
Y min = free

11. Calculating the output

12. Settlement of pile

13. STRESSED ZONE Direction of principal stress

14. LOAD DISPLACEMENT DATA & CURVE
load udl load KN mm
0 0 0.0798
250 70.65 0.2788
500 141.3 0.4779
750 211.95 0.677
1000 282.6 0.8763
1250 353.25 1.076
1500 423.9 1.275
1750 494.55 1.474
2000 565.2 1.674
2250 635.85 1.873
2500 706.5 2.073
2750 777.15 2.273
3000 847.8 2.473
3250 918.45 2.674
3500 989.1 2.875
3750 1059.75 3.076
4000 1130.4 3.279
4250 1201.05 3.482
4500 1271.7 3.687
4750 1342.35 3.898
5000 1413 4.093
5250 1483.65 4.306
5500 1554.3 4.532
5750 1624.95 4.79
6000 1695.6 5.094
6250 1766.25 5.595
6500 1836.9 12.06
6750 1907.55 50.35
7000 1978.2 491.06
7250 2048.85 3359

15. • Ultimate load
• 1. The ultimate load, Qu can be determined as the abscissa of the point where the
curved part of the load-settlement curve changes to falling straight line
• 2. Qu is the abscissa of the point of intersection of the initial and final tangents of the
loadsettlement curve
Ultimate load found
1850kN

16. DETERMINATION OF THE ALLOWABLE LOAD
AS per IS 2911 PART 4 CLAUSE 6.1.5
1.The allowable load Qa is 50 percent of the ultimate load at which the total settlement
amounts to one-tenth of the diameter of the pile.
2. The allowable load Qa is sometimes taken as equal to two-thirds of the load which causes a
total settlement of 12mm.
From criteria 1 load = 954.548 KN
From criteria 2 load = 1224.6 KN
Allowable load = 954.548 KN
Result matched with the field test value

17. REFERENCES:
1. Advanced foundation Engineering 2013 Chapter 7- Prof. T.G. Sitharam Indian Institute of Science, Bangalore
2. IS 2911 PART 4 Code of practice for Design and Construction of pile foundation
3. Foundation analysis and design by Joshep E. Bowles