Some test hydraulic sheeting pile dikes have been built successfully in coastal areas of the Yellow River delta while others are failures. On the practice basis of test pile dikes and results of in-lab flume experiments, main reasons were analyzed for the instability of the piles. In allusion to the instability of pile dikes caused by seabed soil liquefaction and construction characteristics of hydraulic sheeting piles, some prevention suggestions were proposed against failures of pile dikes.
Hydraulic sheeting is a new engineering construction technology arising in recent years. It has been gradually developed into a complete and unique set of construction method after continuous research and testing (Xu et al., 2006). The traditional riprap coastal dikes and caisson breakwaters mainly face such problems as erosion or hollowing of foundation, poor security and stability of dike body and so on. To solve these problems, much money is required to design a wide cross-section of the dike. For example, China constructed riprap sediment retaining dike on each side of the Outer Channel of Huanghua Harbor, and built dike by combination of riprap and placing precast concrete in Yangtze Estuary Channel Engineering. Cross-section of each dike is very wide, and building cost of each project is high (Niu et al., 2006). Besides, the silty foundation strength of the dike will be weakened under the action of wave-induced cyclic loading, which can cause soil liquefaction (Yan et al., 2005). The problem is difficult to solve effectively and can lead to the instability of dike. The hydraulic sheeting pile, the body of which is a precast concrete slab, is inserted into stratum by water-jet cutting strata. The piles are connected by I-beams which are flanked by two semicircular channels. In order to form a whole, the seams between the piles are grouted and sealed.
