中文摘要：

对碎石桩复合地基的时效特性进行研究，根据桩体及桩问土体应力随时间的变化规律，考虑碎石桩复合地基中土体径向、竖向双向排水固结的特点，基于线弹性状态下桩体及桩间土体的应力-应变关系，分别给出考虑时效的桩体与桩间土体竖向应力计算方法，进而建立桩土应力比时效计算的双曲线模型，得到考虑时效的桩土应力比计算方法。研究结果表明：碎石桩复合地基桩土应力比随时间呈双曲线变化，其值与不考虑时效时相比可增大1倍，时效非常明显，在具体计算时不容忽视：双曲线时效模型能够有效地模拟碎石桩复合地基桩土应力比的时效规律：利用桩土应力比时效模型对某工程实例进行计算、分析，理论桩土应力比随时间的变化曲线与实测曲线较吻合。

英文摘要：

Through studying the time effect characteristics of gravel-pile composite foundation, the stresses variation rules of both gravel-pile body and the surrounding soil along with the time were analyzed. Considering the bidirectional drained-consolidated characteristics of the surrounding soil where the water in the soil can be drained vertically and drained laterally, a calculation method considering time effect for stress of pile and that of surrounding soil was put forward according to the linear elastic theory analysis of the stress-strain relationship between pile and surrounding soil. A hyperbolic model of pile-soil stress ratio considering the time effect was established and a new calculation method for pile-soil stress ratio which took the time effect into account was obtained. The results show that the pile-soil stress ratio of gravel-pile composite foundation obeys the hyperbolic curve along with the time and the value of that is bigger than that of the time effect unconsidered, and the time effect of pile-soil stress ratio is so obvious that it can＇t be neglected. Meanwhile, the hyperbolic model of pile-soil stress ratio can effectively adjust itself to the rules of the time effect of pile-soil stress ratio and the calculation result shows that the theoretical calculating curve that describes the relationship between the time and pile-soil stress ratio agrees well with the measured one obtained by the proposed method.