Abstract:

A large scale landslide took place when constructing a port on soft clay foundation. A series of engineering measures were taken for reconstructing the port. Detailed investigation and finite element analysis of slope stability were performed to determine the possible causes of slope failure. In the analysis, the excess pore water pressure in the subsoil caused by piling and the traffic load has been considered especially. The analyzing results show that the failure of the slope was caused by the superposition of several unfavorable operation conditions. It is concluded that the primary cause for the slope failure is under-cutting combined with the low tide level. Furthermore, the pile driving and the traffic load on the slope topside also play a negative role in slope failure. The pile driving construction has a notable impact on slope stability and the safety factor considering the piling effect is much less than that without considering it. However, the influence of the traffic load is not so large relatively. The ground at failed slope was rehabilitated using vibro-sand-piles together with a crushed stone layer on the ground surface for consolidation. Finite element method is applied to simulate the ground improvement effect. The analysis results and successful practice show that the use of sand piles for reinforcement and consolidation is an effective technique for rehabilitating the failed slope.

Key words: slope failure, finite element analysis, dynamic action, excess pore water pressure, ground improvement