A 20-m-long concrete pile is shown in Figure P9.1. Estimate the ultimate point load Q, by a. Meyerhof's method b. Vesic's method c. Coyle and Castello's method Use m = 600 in Eq. (9.26). 9.1 Concrete pile 460 mm x 460 mm Loose sand di = 30° y = 18.6 kN/m3 20 m Dense sand d'2 = 42° y = 18.5 kN/m3 Figure P9.1

Refer to Figure 18.26b. Let L = 15.24 m, fill = 17.29 kN/m3, sat(clay) = 19.49 kN/m3, clay = 20, Hf = 3.05 m, and D = 0.406 m. The water table coincides with the top of the clay layer. Determine the total downward drag on the pile. Assume that = 0.6 clay. FIG. 18.26 Negative skin friction

A 600 mm diameter and 25 m long driven concrete pile carries a column load of 1200 kN. It is estimated that the shaft carries 900 kN and the point carries 300 kN. Determine the settlement of the pile head using the Poulos and Davis method with the following data: Es = 25 MN/m2, Ep = 30,000 MN/m2 and ?s = 0.2.

Estimate the magnitude of k of the clay at a void ratio (e) of 0.9. Use Eq. (2.41). 2.10 Refer to Figure P 2.10 and use these values: • H = 7 m, • H, = 1.75 m, D = 7 m D = 3.5 m Draw a flow net. Calculate the seepage loss per meter length of the sheet pile (at a right angle to the cross section shown). Sheet pile H1 H2 D1 k= 6.5 x 10-4cm/sec Impermeable layer Figure P2.10 = 0.6. 2.11 A sand has the following: D10 = 0.2 mm, D = 0.4 mm, and void ratio e a. Determine the hydraulic conductivity using Eq. (2.38). b. Determine the hydraulic conductivity using Eq. (2.40).

● ● ● Example: 25/1 Consider a concrete pile that is 0.305 m x 0.305 m in cross section placed in sand. The pile is 15.2 m long. The following variations of N60 with depth. are the Estimate Q, using: - Estimate Qf for the pile using: Meyerhof (1976) equation Briaud et al. (1985) - Meyerhof (1976) equation Briaud et al. (1985) - • Determine the allowable load- carrying capacity of the pile based on Meyerhof's method and Briaud's method. Use a factor of safety of 3. Depth below ground surface (m) 1.5 3.0 4.5 6.0 7,5 9.0 10.5 12.0 13.5 15.0 16.5 18.0 19.5 21.0 Neo 8 10 12 14 18 11 17 20 28 29 32 30. 28

Questions A group of 16 piles (4 in each row) was installed in a layered clay soil deposit shown below. The diameter of each pile is 500 mm and their c/c distance is 1m. The length of the pile group is 18m. Estimate the safe load capacity of the group with a factor of safety of 2.50. The adhesion factor (a) between the pile and soil in each soil layer are shown in the figure. 8 m 10 m C= 25 kPa;= 0°; a = 1.0 C₁= 40 kPa;p= 0; a = 0.7 TTTTTT Soil Profile O O O boor Plan View of pile group

A frictional pile with a circular cross- section (diameter = D) is pushed into the soil to a distance (L) and then it is subjected to an axial force (P) on its top end. Derive a formula to calculate the normal stress in any section x. f N/mm2 Cross section

A 600mm diameter open ended steel pipe pile is driven to the soil profile mentioned below. Loose silty sand layer has a Ymoist=16.5kN/m3 and Ysat=18kN/m3, medium dense well graded sand layer has Ysat=20kN/m3 . Laboratory tests have shown that effective internal friction angle of silty sand and well graded sand are 30º and 35º respectively. Calculate the toe bearing capacity by using Vesic/Kulhawy method. Using a FS of 3, calculate the allowable downward load capacity of the pile.

Q1/ For the footing shown in Figure (1), estimate the pile group capacity. 0.6m dia bored pile Clay c=80 kN/m² y-17kN/m² S=1.5 m T L=12 m