Model test of L-shaped caisson quay wall in sand foundation with clay interlayer

Laboratory model tests were conducted to investigate the stability of the L-shaped caisson quay wall installed on the sandy soil with clay interlayer. A total of three L-shaped caisson models were cast to explore the effects of the loading position and the position and thickness of the clay interlayer on their stability under plate loading. The ultimate bearing capacity of the L-shaped caisson quay wall on clay interlayer foundation was reduced by a maximum of 41 % compared to sand foundation. The ultimate bearing capacity was significantly reduced when the distance of the clay interlayer to the rubble mound was less than 1/5 of the quay wall height. The applied surcharge made the lateral earth pressure coefficient higher than the active earth pressure coefficients and triangularly distributed along the L-shaped caisson wall. The modified Beton's method considered the effect of the toe length of the L-shaped caisson could more accurately predict the lateral earth pressure. The failure of the L-shaped caisson quay wall on the clay interlayer foundation has three forms Type-I, Type-II, and Type-Ⅲ which are influenced by the loading position, L-shaped caisson dimensions, and positions of the clay interlayer.