Experimental research of load-bearing and deformation characteristics of rigid pile composite ground

A field test of rigid pile composite ground was conducted. The ground deformation, the axial force on piles and the upper and lower penetration into the cushion and the substratum were measured. Based on these measurements, the pile friction, the pile-soil stress ratio and the load-bearing proportion of piles and soil were investigated. The test results show that piles and soil bear a significant proportion of load due to the adjustment by the cushion, and usually the load-bearing capacity of soil can be fully utilized. The compression of the pile-reinforced layers accounts for a large proportion of the total settlement of the composite ground. The compression of the substratum is relatively small and the proportion of the cushion compression to the total settlement varies with loading levels. At the early stage of loading, soil bears a larger proportion of load, so a local shear failure occurs in soil and a general shear failure develops gradually. Then piles take much more load during the subsequent loading. When load on a pile reaches its load-bearing capacity, the failure of the composite ground happens.