轴对称主动土压力问题的滑移线解  

A solution for axisymmetric active earth pressure by slip line method

作　　者：闫澍旺[1,2] 李嘉[1,2] 闫玥[1,2] 郎瑞卿 纪玉诚[1,2] YAN Shu-wang;LI Jia;YAN Yue;LANG Rui-qing;JI Yu-cheng(State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Yianjin 300072,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072 [2]天津大学建筑工程学院,天津300072

出　　处：《岩土力学》2018年第11期4133-4141,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金青年科学基金项目(No.51709198);天津市自然科学基金(No.16JCQNJC07900;No.13JCZDJC35300)~~

摘　　要：地基中竖向孔支护结构的设计需要以其所受主动土压力为依据,为此常需计算竖向孔开挖后孔壁主动土压力。含竖向圆孔地基是轴对称问题,基于平面应变假设的经典朗肯土压力理论或库仑土压力理论显然不适用,而现有求解轴对称条件下主动土压力方法多采用完全塑性假定或其他假定环向应力与大主应力之比(环向压应力系数?)为常数的方法,理论上不够严谨且误差较大。建立轴对称问题滑移线方程,采用使主动土压力为最大的目标的方法,采用迭代法求解环向压应力系数?,分析了?受土体参数和轴对称竖向孔几何参数影响规律,进而求解轴对称竖向孔孔壁主动土压力的精确值,理论上更为严谨,结果更为合理,并对比平面应变条件下的土压力结果,总结了轴对称条件下主动土压力的规律。Design of vertical hole supporting structure in foundation should be based on its active earth pressure. So it is often necessary to calculate the active earth pressure on the hole wall after excavation of vertical holes. The foundation containing vertical hole is a typical axisymmetric problem, the traditional Rankine or Coulomb solution which is based on plane strain assumption is inapplicable, the existing methods for axisymmetric active earth pressure often presume the ratio of earth pressure and the major principal stress（tangential stress coefficient λ） is constant, such as Harr-Von Karman hypothesis and other similar methods, this assumption is not rigorous in theory and the calculated results have large enough error. In this paper, the slip line field equations for axisymmetric problem are established, the method of maximizing the active earth pressure and the iterative method are used to solve the circumferential compressive stress coefficient the λ, the effects of soil parameters and vertical hole geometry parameters on λ are analyzed, then the accurate value of active earth pressure can be determined. This method is more rigorous in theory and the result is more reasonable compared to that under plane strain assumption condition.

关 键 词：轴对称竖向孔 主动土压力 滑移线法 环向应力系数 

分 类 号：TU432[建筑科学—岩土工程]