路堤荷载作用下碎石桩复合地基桩土应力比计算及试验研究

深入分析了路堤等柔性荷载作用下碎石桩复合地基的工作机理，对路堤-碎石桩-桩间土系统进行合理简化，建立了桩土应力比计算模型，并给出关键参数的求解过程。基于最小势能原理，导得路堤荷载下碎石桩复合地基桩土应力比计算解析表达式，结合大型室内模型试验，通过对比试验过程中的全程监测数据，验证了理论解的正确性。探讨了各主要影响因素与桩土应力比之间的关系，结果表明：桩土模量比和置换率是应力比的主要影响因素，路堤高度与路堤材料的影响次之；当路堤高度较小时，随着高度增加，桩土应力比提高明显；但当路堤高度增大到一定值时，桩土应力比基本不变；增大填料剪切模量可略微增大应力比。

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.