The soft clay in the subsoil of the north and south guide dikes was softened under the action of heavy winds and waves and the caissons on the subsoil were settled and displaced greatly.

• 长江口深水航道治理工作南北导堤地基中的软黏土在大风浪作用下,曾因黏土软化而使其上的沉箱发生较大沉降及位移,欲采用排水板预压的加固方案。