K_0固结饱和土体柱孔扩张问题一种相似解法  

A SIMILARITY SOLUTION METHOD OF CYLINDRICAL CAVITY EXPANSION IN K_0 CONSOLIDATED SATURATED SOILS

作　　者：刘时鹏[1] 施建勇[2,3] 雷国辉[2,3] 张兴胜[1] 

机构地区：[1]华北水利水电大学资源与环境学院,郑州450011 [2]河海大学岩土力学与堤坝工程教育部重点实验室,南京210098 [3]河海大学岩土工程科学研究所,南京210098

出　　处：《工程力学》2016年第12期128-134,共7页Engineering Mechanics

基　　金：国家自然科学基金面上项目(50878075);华北水利水电大学高层次人才科研启动项目(201406)

摘　　要：采用能够考虑原状土体实际K_0固结特性弹塑性本构模型的屈服面方程为屈服准则,根据柱孔扩张基本平衡方程和相似解方法,对处于天然状态下的饱和土体柱孔扩张问题进行求解,推导出从零初始孔径柱孔扩张问题在小应变情况下塑性区的有效应力、超静孔隙水压力半解析解答。同时,通过算例对比分析表明:饱和土体在柱孔扩张后其塑性区超静孔隙水压力沿径向呈衰减趋势变化,其大小随着超固结比的增大而增大,孔壁周围土体有效应力下降明显,随着超固结比的增大,有效应力的减小趋势有所降低;考虑K_0固结影响的本文解答所得到的超静孔隙水压力大于修正剑桥模型的解答,扩孔完成后其周围土体有效应力下降大于后者。Based on the equilibrium equation and similarity solutions method, the elasto-plastic constitutive model which considers actual K_0 consolidated soils characteristics is selected in the analysis of saturated soils cylindrical cavity expansion. According to the zero radius expansion and small strain, the semi-analytical solutions of plastic zone effective stresses, the excess pore water pressure around the cylindrical cavities are obtained. Meanwhile, the comparative analysis of an example indicates that the excess pore water pressure induced by cylindrical cavity expansion in saturated soils decreases in the radial direction and its value increases with the over-consolidation ratio, the effective stress in periphery soil of hole-wall inclines obviously and its value shows a contrary tendency to the over-consolidation ratio. The results of comparison between the K_0 consolidated soil constitutive model and modified Cam-clay model indicate that the excess pore water pressure calculated from the K_0 consolidated soil constitutive model is obviously greater than that from the solutions based on the modified Cam-clay model, but the effective stress decreases more significantly than the latter.

关 键 词：K0固结土体本构模型 柱孔扩张 相似解法 超固结比 超静孔隙水压力 

分 类 号：TU470[建筑科学—结构工程]