Question 15.28: A square pile group similar to the one shown in Fig. 15.27 p...

The negative frictional load on the group is the maximum of [(Eqs (15.82) and (15.83)]

F_{n g}=n F_{n} (15.82)

F_{n g}=s L_{n} P_{g}+\gamma L_{n} A_{g} (15.83)

(a) F_{n g}=n F_{n}, and (b) F_{n g}=s L_{n} P_{g}+\gamma L_{n} A_{g}

where P_{g}=4 \times 3=12 m , A_{g}=3 \times 3=9 m ^{2}, c_{u}=60 / 2=30 kN / rn ^{2}

(a) F_{n g}=9 \times 3.14 \times 0.3 \times 3 \times 30=763 kN

(b) F_{n g}=30 \times 3 \times 12+15 \times 3 \times 9=1485 kN

The negative frictional load on the group = 1485 kN.