循环荷载下桩承加筋土复合地基承载特性数值正交试验研究

Numerical Orthogonal Test Research on Bearing Characteristics of Pile-supported Reinforced Soil Composite Foundation Under Cyclic Load

采用PLAXIS 3D软件对循环荷载下刚柔性桩承加筋土复合地基承载变形特性进行数值模拟,通过正交试验探究桩帽尺寸、土工格栅层数、柔性桩桩长以及格栅刚度等影响因素对循环荷载下刚柔性桩承加筋土复合地基变形的影响,并通过数值对比试验分析了影响最大的两个因素对复合地基承载变形特性的影响。研究结果表明,刚性桩桩帽尺寸对循环荷载下刚柔性桩承加筋土复合地基位移的影响最大,而柔性桩长度对其影响最小;土工格栅层数对循环荷载下刚柔性桩承加筋土复合地基位移的影响大于土工格栅刚度。增大刚性桩桩帽尺寸能明显减小循环荷载下刚柔性桩承加筋土复合地基的沉降和底层土工格栅张拉力,且能有效提升桩的总荷载分担比。增加土工格栅层数能小幅减小刚柔性桩承加筋土复合地基沉降,且能明显减小底层土工格栅张拉力,并稍许增大桩的总荷载分担比。刚性桩桩帽尺寸改变对复合地基承载变形的影响最大,建议在工程中优先考虑。

The research on deformation characteristics and load sharing ratio of rigid-flexible pile-supported reinforced soil composite foundation under cyclic loading was not deep enough.Therefore,numerical simulation on rigid-flexible pile-supported reinforced soil composite foundation under cyclic loading was carried by using the software PLAXIS 3D.The influence of pile cap size,geogrid layer number,flexible pile length and goegrid stiffness on deformation of rigid-flexible pile-supported reinforced soil composite foundation under cyclic load was analyzed through the orthogonal tests.The influence of two factors with the greatest influence on bearing and deformation characteristics of composite foundation was analyzed through the numerical comparative tests.The results showed that the rigid pile cap size had the greatest influence on the displacement of the rigid-flexible pile-supported reinforced soil composite foundation under cyclic load,while the flexible pile length had the minimal impact.The influence of the geogrid layer number on displacement of reinforced soil composite foundation was greater than that of the geogrid stiffness.Increasing the rigid pile cap size could significantly reduce the settlement of the rigid-flexible pile-supported reinforced soil composite foundation and the tension of the underlying geogrid under cyclic load.Increasing the number of geogrid layers could slightly reduce the settlement of rigid-flexible pile-supported reinforced soil composite foundations and significantly decreased the tensile force of the underlying geogrid under cyclic load.Increasing the rigid pile cap size and the geogrid layer number could also improve total load sharing ratio of the pile.The change of rigid pile capsize had the greatest impact on the bearing and deformation characteristics of the composite foundation.It is firstly recommended to consider the size of pile cap in the engineering application.