Calculation and model test for pile-soil stress ratio of gravel pile composite foundation under embankment load

Working mechanism of gravl pile composite foundation under embankment loads is deeply analyzed. The system of embankment-pile-soil is simplified properly; the calculation model of pile-soil stress ratio is established; and the solving process of key parameters is given. The principle of minimum potential energy is adopted to deduce the formula of pile-soil stress ratio under embankment loads. Compared to the results which is observed in large-scale laboratory model test, the method put forward can satisfy the engineering requirement. Factors influencing the stress ratio are studied. The results show that the stress ratio is significantly affected by pile-soil modulus ratio and displacement ratio, while embankment height and embankment material less effect on it. The pile-soil stress ratio increases when the embankment height increases, it becomes stable when height comes to a fixed value; and it increases slightly when shear modulus of embankment fill increases.