基于非线性Mohr-Coulomb强度准则下的扩孔问题解析  

Analytical solution of cavity expansion with the non-linear Mohr-Coulomb failure rule

作　　者：邹金锋[1,2] 彭建国[2] 张进华[2] 罗恒[1] 安爱军[1] 

机构地区：[1]中南大学,湖南长沙410075 [2]湖南省交通规划勘察设计院,湖南长沙410008

出　　处：《土木工程学报》2009年第7期90-97,共8页China Civil Engineering Journal

基　　金：国家自然科学基金(50408020);教育部新世纪优秀人才计划基金(05-0686);铁道部科技重点(2008G032-3)

摘　　要：将圆孔周围的围岩分为弹性和塑性应力区,考虑土体受力后的剪胀特性,根据Mohr-Coulomb非线性强度准则、应力平衡条件、大小变形理论和非关联流动准则,推导出排水情况下土体发生大、小变形时扩孔问题的塑性区应力、应变和位移场解析,并给出大、小变形情况下塑性区半径和极限扩孔压力的非线性解答。与现有理论的计算结果和现场实测结果进行对比结果表明,上述理论具有一定的有效性。通过分析可知,大变形时的塑性应变比小变形时的大;随着m值的增大,扩孔压力逐渐增大且与rp/au为非线性关系;大变形时的扩孔压力要比Vesic等人的理论值偏小。Using the non-linear Mohr-Coulomb failure criterion as the initial yield function and considering the shear dilatation characteristics, the soil around the cavity is divided into elastic and plastic zones. The non-linear Mohr- Coulomb failure criterion, the equilibrium principle, and the large and small strain theories are employed for the plastic zone, and analytical solutions of the stress, strain, and displacement fields for cavity expansion are presented with the non-associated flow rules for the shear dilatation characteristics. A series of analyses of strain and limit cavity pressure with different dilation parameters for large and small strains in the plastic zone conducted. The results of the present theory, Vesic＇s theory and in situ test are compared to verify the present theory.

关 键 词：剪胀 非线性Mohr—Coulomb强度准则 扩孔压力 塑性区半径 大变形 非关联流动准则 

分 类 号：TU432[建筑科学—岩土工程]