自平衡法荷载沉降曲线的数值模拟分析

从自平衡法和静载荷法的加载机理入手,分析了自平衡法荷载沉降曲线的特点,重点讨论了桩周土为粘性土时,自平衡法中上段桩体负摩擦转换成正摩擦时,转换系数K的合理取值范围。运用AN-SYS有限元软件,建立了三维空间有限元模型,考虑桩与桩周土相互作用接触面滑移特性,对自平衡法及静载荷法进行模拟计算及对比分析,得到桩周土为粘性土且转换系数K取值1.15～1.20时,2种方法的荷载沉降曲线较为吻合。

Numerical simulation analysis of load-displacement curves using self-balanced testing method

Based on the loading mechanism of the self-balanced testing method and static load method,the characteristic of self-balanced load-displacement curves were analyzed.In self-balanced testing method,when the negative friction changed into positive friction on the central-to-top pile and the soil around the pile was clay,the reasonable range of the conversion coefficient K was emphatically discussed.Considering the sliding characteristic of interaction contact surface between the pile and the soil around it,a 3-dimensional spatial FEA model was built using ANSYS FEA software.By comparing the numerical simulation calculation of self-balanced testing method and static load method,the results show that the load-displacement curves of the two methods are most consistent when the conversion coefficient K is between 1.15 to 1.20 and the soil around the pile is clay.