This benchmark describes the design of a
3x3 pile group subjected to a combination of vertical loads,
and moments, and embedded into the stiff London Clay .
The bored cast-in-situ reinforced concrete piles are 17m long,
0.9m in diameter, with a centre-to-centre spacing of three pile
diameters, and with the underside of the pile cap assumed at
the top of the London Clay. A profile of undrained shear strength
(Cu) of 50 + 9.4z kPa has been adopted, where z is the depth
in m below the top of the London Clay.
For the axial response,
the profile of soil modulus has been derived from the correlation
Es = 400Cu for the linear analyses and from Es = 1500Cu for
the non-linear analysis. For the lateral response, the profile
soil modulus has been assumed to increase linearly with depth
from a value of zero at the top of the London Clay at a rate
of 4.14MN/m3 for the linear analyses and 6.15MN/m3 for the
The applied vertical loads (V) result from
effect of live and dead loads, whereas the horizontal loads
(H) and moments (M) are generated by the high-speed trains
braking and accelerating. The loads acting on the cap have been
as V = 14200kN, H = 470kN and M = 3200kNm.