Pile Design C Phi Soil

Location : Project :

BORE PILES IN 0

1

C − φ SOIL

INPUT

Depth Below GL or  Chart Datum m 0 -0.5 -1 -3.5 -4 -7 -7.5 -9.5 -10 -11.5 -12 -14 -16 -18 -20 -22

-14

Navlakhi

Soil Properties

Cu kg/cm2 0 0.00 0.29 0.29 0.07 0.07 0.07 0.07 0.04 0.04 0.52 0.52 0.52 0.52 0.52 0.52

Soil Density

φ Degree 0 0 13 13 15 20 20 20 15 15 15 15 15 15 15 20

γ kg/cm3 0 0 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6

Coefficient of Earth Pressure Adhesion Factor Design Load Pile Dia. In CM Factor of safety for Skin Friction Factor of safety for end bearing Factor of safety overall

 K 

SAFE AT

-14

δ

tonne cm

1 l 100 100 2 2 2.5

VK BHAVADASAN

VK Bhavadasan

12th January 2004

08/13/2011

2

Depth vs Load 400

350

Ultimate Skin Friction

Ultimate End Bearing

Total safe Load

Design Load

300

250

      d      a      o        L

200

150

100

50

0 0

-0.5

-1

-3.5

-4

-7

-7.5

-9.5

-10

-11.5

-12

-14

-16

-18

-20

-22

Depth

SAFE AT

-14

VK Bhavadasan

12th January 2004

08/13/2011

Soil Bearing Capacity at various Levels

Deph Of Pile

0 -0.5 -1 -3.5 -4 -7 -7.5 -9.5 -10 -11.5 -12 -14 -16 -18 -20 -22

VK Bhavadasan

Ultimate Skin Friction 0 0 8.045 48.271 53.611 94.700 101.548 128.941 133.700 147.976 157.494 195.567 233.640 271.713 309.786 353.892

Ultimate End Bearing 0 0 17.310 38.516 41.840 51.028 51.028 31.479 28.863 28.863 63.146 63.146 63.146 63.146 82.695 36.757

Total safe Design Load Load 0 100 0 100 10.142 100 34.715 100 38.180 100 58.291 100 61.031 100 64.168 100 65.025 100 70.736 100 88.256 100 103.485 100 118.714 100 133.943 100 156.992 100 156.259 100

12th January 2004

08/13/2011

Piles in Soil Intermediate Between Sand and Clay

3 1] When Piles are installed in SANDY CLAY, which are predominantly Cohesive in character the Skin friction and end bearing resistance should be calculated assuming Φ =0 2] When Pile is installed in CLAYEY SAND where the Cohesion is relatively small, the carrying capacity shall be calculated assuming C = 0 3] In SANDY CLAY or SANDY SILTS and SILTY or CLAYEY SANDS, which possess appreciable cohesion and frictional components, can be termed as C - Φ soil, and the ultimate capacity can be estimated using equation below.

Q = A q up

 K  σ  

 ∑ C a 

 p ult 

δ

υ ta n φ a

 d 

A

 s

Granular Soil ULTIMATE POINT RESISTANCE (General Approach) The ultimate point resistance does not necessarly increase with depth, and vertical effective stress is not equal to the effective overburdon pressure but reaches a limiting value Zc. The ratio Zc/D , falling in the range of 5 to 20 is given in Fig. 03 There is a wide variation in the values recomented for Nq as showen in Fig. 05. Nq value established by Berezantsev (1961) confirm to practical criteria of Pile faliure. For values of Nq, the graph provided in IS 2911 is adopted which is based on Berezantsev's curve up to 35 degree and Vesic's curve beyond 35 degree, as shown in Fig. 04. ULTIMATE SKIN FRICTION The value of skin friction coefficient is influenced by many factors; including angle of internal friction, method of instalation, pile material, shape etc. For bore pile in which bore holes are stablised by bentonite this value may be estimated assuming K δ  = 1

Cohesive Soil ULTIMATE POINT RESISTANCE (General Approach) The value of Nc used in the design is as that proposed by Skempton (1961). For circular area, the value increases from 6.14 to a limiting value of 9 for depths greater than 4 times diameter.The values are shown in table No. 01 PILE - SOIL ADHESION The pile - soil adhesion depends on various factors. For simplicity, Ca has been related to undrained cohesion Cu of soil. The ratio Ca / Cu is termed as adhesion factor. The adhesion factor is taken as shown in Figure No. 01.The Australian Code AS 2159 provides higher values of adhesion factor, while Dr.NV Nayak propose adhesion factor as 1 for bored cast in situ RCC piles in all clay of any consistency. Two values for adhesion factor are drawn in the graph. The lower value is as given in Ref. Book by Dr. NV Nayak, (p.No.166). The Higher values as per Australian Code. By entering "L" or "H" appropriate value for  adhesion factor can be selected.

VK Bhavadasan

12th January 2004

08/13/2011

4 Fig. 01

ADHESION FACTOR  1.20 1.00 r

ot c a F n oi s

e h d A

0.80 0.60 0.40 0.20 0.00 0.0

0.5

1.0

1.5

2.0

2.5

Cohesion kg/cm2

Adhesion Factor

Adhesion Factor  as per Australian Code Fig. 02  Nc

10 9 8 7 6

Table 01 Cohesive Soils

5

 Nc

4

End-bearing Nc L/d 0 6.14 1 7.6 2 8.3 3 8.8 4 9

3 2 1 0 1

2

3

4

5

Fig. 03 Critical Depth

25 20 15       D       /      z

10 5 0 25

VK Bhavadasan

27

29

31

33

35

12th January 2004

37

39

41

43

45

08/13/2011

Fig. 04

5

BEARING CAPACITY FACTOR - Nq 1000.00

100.00

    q         N

10.00

1.00 2 1

4 3

6 5

8 7

9

10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 Angle of internal friction

VK Bhavadasan

12th January 2004

08/13/2011

6 Fig. 05

bhavadasanv@yahoo.com

VK Bhavadasan

12th January 2004

08/13/2011

VK Bhavadasan

12th January 2004

08/13/2011

VK Bhavadasan

12th January 2004

08/13/2011

VK Bhavadasan

12th January 2004

08/13/2011

VK Bhavadasan

12th January 2004

08/13/2011

1 Base diam Shape

l 100 r  

su 0 10

1 1

20

1

L

mm Depth

Pile Adhesion Dia Factor 100 100 1 100 0.97 100 0.97 100 1 100 1 100 1 100 1 100 1 100 1 100 0.65 100 0.65 100 0.65 100 0.65 100 0.65 100 0.65

l

Depth 0 -0.5 -1 -3.5 -4 -7 -7.5 -9.5 -10 -11.5 -12 -14 -16 -18 -20 -22

l Cu 0 0 0.29 0.29 0.07 0.07 0.07 0.07 0.04 0.04 0.52 0.52 0.52 0.52 0.52 0.52

Depth Incriment 0.5 0.5 2.5 0.5 3 0.5 2 0.5 1.5 0.5 2 2 2 2 2

Shaft Adhesion cu Adhesion For as per A 0 1 1 0.1 1.00 1.00

α

C As

0.000 4.419 22.093 1.131 6.786 1.131 4.524 0.550 1.649 5.309 21.237 21.237 21.237 21.237 21.237

Skin Friction tan phi

Kd 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

0.0000 0.2309 0.2309 0.2679 0.3640 0.3640 0.3640 0.2679 0.2679 0.2679 0.2679 0.2679 0.2679 0.2679 0.3640

0 1 2

0.00 5 5

0.00 1.09 1.20

0.2

0.97

1.00

3

5

1.31

30 1 0.3 40 1 0.4 50 0.91 0.5 60 0.78 0.6 70 0.7 0.7 80 0.62 0.8 90 0.56 0.9 100 0.52 1.0 110 0.48 1.1 120 0.44 1.2 130 0.41 1.3 140 0.39 1.4 150 0.37 1.5 160 0.35 1.6 170 0.34 1.7 180 0.33 1.8 190 0.32 1.9 200 0.32 2.0 Australian code recomends Better Adhesoin Factor

0.86 0.74 0.65 0.57 0.49 0.42 0.37 0.33 0.31 0.30 0.30 0.30 0.30 0.3 0.30 0.30 0.30 0.30

1.00 1.00 0.9 0.78 0.7 0.62 0.56 0.52 0.48 0.44 0.41 0.39 0.37 0.35 0.34 0.33 0.32 0.32

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5

1.43 1.57 1.72 1.89 2.09 2.31 2.53 2.82 3.11 3.44 3.83 4.20 4.69 5.26 5.87 6.58 7.31 8.22 9.31 10.57 11.91 13.48 15.42 17.66 20.23

VK Bhavadasan

Skin Friction 0.000 3.626 18.132 4.209 34.303 5.717 22.869 4.209 12.627 4.209 16.836 16.836 16.836 16.836 22.869

10 9 8 7 6 5 4 3 2 1 0 1

400.

350.

300.

250.

200.

08/13/2011

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

VK Bhavadasan

5.1 5.23 5.41 5.62 5.83 6.2 6.5 7 8 9.5 12 15 18 20 20 20 20

23.33 26.79 31.05 35.73 41.21 47.86 55.46 64.57 75.16 87.90 101.62 120.78 145.88 181.97 228.56 295.00 380.20

.

150.

100.

50.

0.

08/13/2011

Total Ultimate Skin Friction

Safe Skin Friction

0 0.00 8.05 48.27 53.61 94.70 101.55 128.94 133.70 147.98 157.49 195.57 233.64 271.71 309.79 353.89

0 4.02 24.14 26.81 47.35 50.77 64.47 66.85 73.99 78.75 97.78 116.82 135.86 154.89 176.95

L/D

0.5 1 3.5 4 7 7.5 9.5 10 11.5 12 14 16 18 20 22

Nc

6.14 7.6 8.8 9 9 9 9 9 9 9 9 9 9 9 9

Soils Nc

Cohesive End-bearing qe=9Cu if L/d>4

-18

Nc 6.14 7.6 8.3 8.8 9

2

0

0

0.00 17.31 20.04 5.09 5.09 5.09 5.09 2.47 2.47 36.76 36.76 36.76 36.76 36.76 36.76

Depth -22 -20

qe=NcCu if L/d<=4 Table 01 L/d 0 1 2 3 4

CNc

3

4

5

-16 -14 -12 -11.5 -10 -9.5 -7.5 -7 -4 -3.5 -1 -0.5 0 -14

Depth

0 -0.5 -1 -3.5 -4 -7 -7.5 -9.5 -10 -11.5 -12 -14 -16 -18 -20 -22

Depth

Cumilative Depth

0.5 1 3.5 4 7 7.5 9.5 10 11.5 12 14 16 18 20 22

Critical Depth Z/D

h

0 5 5 5 5 5 5 5 5 5 5 5 5 5 5

0 1 3.5 4 5 5 5 5 5 5 5 5 5 5 5

No of pile llowable Loa esign Load 22 156 100 1 20

157

100

18 16 14 12 11.5 10 9.5 7.5 7 4 3.5 1 0.5 0

134 119 103 88 71 65 64 61 58 38 35 10 0 0

100 100 100 100 100 100 100 100 100 100 100 100 100 _ 100

1 1 1 1 2 2 2 2 2 2 3 3 10    _  1 1

SAFE AT 0

0

0

VK Bhavadasan

08/13/2011

0

0

0

0 3 1

7 5

9

11 15 19 23 27 31 35 39 43 13 17 21 25 29 33 37 41 45

VK Bhavadasan

08/13/2011

Density

0 0 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6

Nq

0.001 3.436 3.436 4.200 7.311 7.311 7.311 4.200 4.200 4.200 4.200 4.200 4.200 4.200 7.311

QNq

0.00 0.00 18.47 36.75 45.94 45.94 26.39 26.39 26.39 26.39 26.39 26.39 26.39 45.94 0.00

Ultimate End Bearing

0 0.00 17.31 38.52 41.84 51.03 51.03 31.48 28.86 28.86 63.15 63.15 63.15 63.15 82.70 36.76

Deph Of Pile 0 -0.5 -1 -3.5 -4 -7 -7.5 -9.5 -10 -11.5 -12 -14 -16 -18 -20 -22

Ultimate Skin Friction 0 0.000 8.045 48.271 53.611 94.700 101.548 128.941 133.700 147.976 157.494 195.567 233.640 271.713 309.786 353.892

Ultimate End Bearing 0 0.000 17.310 38.516 41.840 51.028 51.028 31.479 28.863 28.863 63.146 63.146 63.146 63.146 82.695 36.757

Total safe Load 0 0 10.14 34.71 38.18 58.29 61.03 64.17 65.03 70.74 88.26 103.49 118.71 133.94 156.99 156.26

-12

VK Bhavadasan

08/13/2011

VK Bhavadasan

08/13/2011

Design Load 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Safe End Bearing 0 10.14 34.71 38.18 58.29 61.03 64.17 65.03 70.74 88.26 103.49 118.71 133.94 156.99 156.26

VK Bhavadasan

0 0 8.66 19.26 20.92 25.51 25.51 15.74 14.43 14.43 31.57 31.57 31.57 31.57 41.35 18.38

Total Pile Capacity 0 0 12.68 43.39 47.73 72.86 76.29 80.21 81.28 88.42 110.32 129.36 148.39 167.43 196.24 195.32

08/13/2011

VK Bhavadasan

08/13/2011