- 3x5 Group Pile Driven Single Pile 2m Sand 30 M Thick 18 7 Kn M 38 Deg 19 5 Kn M 0 40 Deg C 0 Dense Silty Sa 1 (110.64 KiB) Viewed 17 times
3x5 Group Pile (driven). Single Pile 2m Sand: 30 m thick. -18.7 kN/m. - 38 deg, -19.5 kN/m 0-40 deg, c'-0 Dense Silty sand =19.7 kN/m * = 43 deg, c=0 Fig. 1 Problem: Fig.1 shows the soil profile at a site containing 30 m thick sand underlain by deep silty sand. Groundwater level is at 2m below ground level. Pile diameter = 0.35m, Pile length is 20 m. A single driven concrete pile is loaded to its ultimate capacity in compression. Load measured on the pile is P4 at 7m below ground, Po at 10m. P20, at 20m. Determine the following: 1. skin friction fs at 7m below ground surface in kPa 2. skin friction f, at 10m below ground surface in kPa 3. magnitude of P - P10 (the difference between P, and P0) in kN 4. magnitude of Pzo in kN 5. settlement (in mm) of a single pile for an applied load of 400 kN, given that 30% of the applied load is carried at the tip. 6. the settlement (in mm) of a pile group (3x5 group with 1.05m center-to-center spacing) for an applied Group Pile load of 6,000 KN. f=Koy' tand; K=1.5. 8=0.95 . fəa*C; a=0.21+0.26 p./c. <1.0; p.=101 kPa. Group End Bering in Clay=C. N.*B.*Ls; N. = 5 [1+D/(5B.)] * [1+B./(5L)] < 9 End bearing in sand =q N, Ap. End bearing in clay = 9C, Api Bearing Capacity Factors deg 30 35 40 45 N 95 190 Si = (Qwt + 5 Qus)/(Ap Ep); Approx 5 = 2/3; S2 = QwtCp/(d*quit,tip); S3 = QwsC/(l*quit,tip); Cs = (0.93 +0.16(l/d)°-5) Cp: I=pile length, d=pile diameter. Sgroup - Ssingle [B/d]0.5 n = 1-[(n-1)m + (m-1)n)/(90mn); tan(0) = d/s, is in deg. n=no of piles on row, m = no of piles in column OR n = 0.5 + 0.05 (s/d) for s/d < 5 and n = 1 for s/d greater than 5. Yw = 9.8 kN/m Econe = 25 GPa. Value of 27 48 Soil Type Driven Piles Bored Piles D. = 10B for loose sands D. - 15B for medium dense sands Sand dense to loose Clay stitt to soft) Silt dense to loose 0.02 to 0.04 0.02 to 0.03 0.03 to 0.05 0.09 to 0.18 0.03 to 0.06 0.09 to 0.12 D. - = 20B for dense sands