Abstract:Long-short pile composite ground can achieve great economical benefit when it is used in low-high-rise building in deep-thick soft soil area. Previous approaches mainly depend on experts¢ experience,so relevant papers are seldom seen in this field. This paper presents a synthetic approach to resolve how to design long-short pile composite ground,which includes choosing foundation schemes,calculating long-short pile length and cushion in a typical project. Long-short pile composite ground was chosen according to the factors such as loading,soil condition and ground bearing capacity,price and soil squeezing effect. The length of short pile is decided by soft soil strength of short pile tip in terms of analysis on bearing capacity of short pile. The length of long pile is determined by total settlement after specific bearing layer is chosen. Compared with experiments on cushion materials and thicken,a better cushion composed of mixed gravel,slab stone and sand is proposed in this project. Experimental data show that bearing capacity and settlement in this project meet the requirements of design.