基于广义SMP破坏准则的柱形孔扩张问题理论分析  

Theoretical analysis of cylindrical cavity expansion based on extended SMP criterion

作　　者：栾茂田[1] 李波[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室

出　　处：《岩土力学》2006年第12期2105-2110,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.50179006);教育部跨世纪优秀人才培养计划研究基金资助项目(教技函[1998]2号);中国科学院武汉岩土力学研究所前沿领域基础研究基金项目资助(No.Q110305)

摘　　要：采用应力跌落的简化应力-应变模型考虑土的应变软化特性,同时采用简化的体积应变εv与大主应变ε1及大主应变ε1与小主应变ε3之间的相互关系反映土的剪胀特性,根据空间准滑动面(SMP)理论和平面应变轴对称问题的柱形孔扩张基本方程,推导并给出一般黏性土中柱形孔扩张问题的应力场、应变场、位移场、塑性区半径和孔扩张压力。通过算例分析,探讨了土的剪胀因素、软化特性对孔扩张问题的影响程度。为了反映中主应力的影响,将本文解与基于Mohr-Coulomb破坏准则的解答进行了比较。计算结果表明,土的剪胀性和软化特性及中主应力对孔扩张问题的影响是显著的,基于Mohr-Coulomb破坏准则的孔扩张解答往往偏于保守。In order to incorporate the strain-softening and shear dilatation behavior of geomaterials in the analysis, a strain-softening stress-strain model with stress-dropping and a simplified model of εv-ε1 and ε-ε3 are adopted. Based on the extended spatial mobilization plane （SMP） theory, the governing equations of axisymmetric problem in the plane strain condition, the partial differential equations for the boundary-value problem of cavity expansion in cohesive soils are established; and the closed-form solutions of stresses, strains, displacements in the elastic and plastic regions are obtained. Consequently. the maximum radius of plastic region and ultimate cavity pressure are solved tbr cylindrical cavity expansion. Based on numerical results, the strain-softening rate and the effects of soil dilatancy on expansion of cylindrical cavity are examined. Also a comparative study is made for the present solution and current solution based on Mohr-Coulomb criterion in order to display the effect of intermediate principal stress. The results indicate that soil strain-softening and shear dilatancy as well as the intermediate stress have considerable effect on both ultimate cavity pressure and maximum radius of plastic region in the cylindrical cavity expansion.

关 键 词：剪胀 应变软化 推广的空间准滑动面理论 柱形孔扩张 弹塑性分析 

分 类 号：TU43[建筑科学—岩土工程]