The bearing characteristics of dry jet mixing pile composite ground are investigated. The stresses on pile and soil and their variation under flexible load have been measured; and pile-soil stress ratio of composite ground with DJM pile under flexible load and its variation with the load have been studied. The investigation indicates that the static loading test curves of composite ground are of gradually varied shape; it is feasible that load corresponding to relative settlement ratio s/b =0.01 is taken as basic bearing capacity value of composite ground according to relative settlement method. Because of running compensation effect of cushion

pile-soil stress ratio n changes comparatively gentle with load. Pile-soil stress ratio n changes about 1.73-6.83; its average value is 3.20.