Solve Problem 12.13 using Eqs. (12.59) and (12.60).

Problem 12.13

A concrete pile 406 mm × 406 mm in cross section is shown in Figure P12.13. Calculate the ultimate skin friction resistance by using the

a. α method [use Eq. (12.61) and Table 12.11]

b. λ method

c. β method

Use ϕ'_R = 20° for all clays, which are normally consolidated.

Table 12.11

Variation of a (Interpolated

Values Based on

Terzaghi et al., 1996)

c_u/p_a ……………………………. α

≤ 0.1 ………………………….. 1.00

0.2 ………………………….. 0.92

0.3 ………………………….. 0.82

0.4 ………………………….. 0.74

0.6 ………………………….. 0.62

0.8 ………………………….. 0.54

1.0 ………………………….. 0.48

1.2 ………………………….. 0.42

1.4 ………………………….. 0.40

1.6 ………………………….. 0.38

1.8 ………………………….. 0.36

2.0 ………………………….. 0.35

2.4 ………………………….. 0.34

2.8 ………………………….. 0.34

Note: p_a = atmospheric pressure ≈ 100 kN/m²

Eq. (12.61)

Figure P12.13.

Eq. (12.58).

Eqs. (12.59)

Eqs. (12.60)

Q, = Efp AL = Eac,p AL