Experimental research on bearing features of CFG pile composite ground and vibrating sinktube detritus pile composite ground on saturated loess

The large oil tank group in Lanzhou, which is a part of the China's state key project—the western oil pipe line project, is constructed on the saturated loess stratum for the first time in China. Due to the low natural bearing capacity, only 60 kPa, that the ground treatment should adopt the CFG pile composite method is applied in oil tank area. The vibrating sinktube detritus pile composite method is applied in process plant area. The dynamic penetration tests, single-pile static load tests and composite foundation static load tests are carried out to determine the bearing capacity of the composite foundation. Through the field experimental research, it is found that the bearing capacity of the vibrating sinktube detritus pile composite is only 66 kPa, which does not meet the design requirements of 70 kPa. The bearing capacity of CFG pile composite is 275 kPa, which can meet the design requirements of 270 kPa. The bearing features of the CFG pile composite ground and the vibrating sinktube detritus pile composite ground are discussed to provide references for similar projects.