考虑砂土颗粒破碎的柱孔扩张问题弹塑性分析  

Elasto-plastic analysis of cylindrical cavity expansion considering particle breakage of sand

作　　者：郑金辉[1] 齐昌广[1] 王新泉[2] 单艳玲 赖文杰 王梁志 ZHENG Jin-hui;QI Chang-guang;WANG Xin-quan;SHAN Yan-ling;LAI Wen-jie;WANG Liang-zhi(School of Civil and Environmental Engineering,Ningbo University,Ningbo 315211,China;Department of Civil Engineering,Zhejiang University City College,Hangzhou 310015,China)

机构地区：[1]宁波大学土木与环境工程学院,浙江宁波315211 [2]浙江大学城市学院土木工程系,浙江杭州310015

出　　处：《岩土工程学报》2019年第11期2156-2164,共9页Chinese Journal of Geotechnical Engineering

基　　金：浙江省自然科学基金项目(LY18E080010,LQ18E080006);宁波市自然科学基金项目(2017A610317)

摘　　要：目前对砂土中圆孔扩张问题的研究均未考虑到砂土颗粒的破碎以及剪胀特性,且为了方便后续求解,很多学者对剪应力,剪切模量等计算参数做了简化,使得最终的求解结果无法准确反映实际情况。针对上述问题,采用考虑颗粒破碎和剪胀特性的砂土临界本构模型,在塑性区联合相关流动法则和拉格朗日分析法,将传统的欧拉描述下的柱孔扩张问题转换为基于拉格朗日描述的带初值的一阶非线性常微分方程组,最终通过数值方法得到砂土中柱孔扩张问题的半解析精确解,并通过算例分析了土体初始应力对扩孔结果的影响。结果表明,颗粒破碎和初始应力对孔周应力和塑性区半径影响巨大,两者共同作用使得土体在扩孔期间表现出不同的剪胀/剪缩特性;此外,高初始应力下的孔周土体在扩孔期间难以到达临界状态。The current studies on the cavity expansion in sand have not considered the breakage and dilatancy of sand particles. In order to facilitate the subsequent calculation, many scholars have simplified the calculation parameters such as shear stress and shear modulus, so the final results do not reflect the actual situation accurately. In response to the above problems, a critical constitutive model for sand considering particle breakage and dilatancy is used. Employing the associate flow rules and the Lagrangian analysis method in the plastic zone, the cylindrical cavity expansion problem described by the traditional Euler description is converted into a first-order nonlinear ordinary differential equation with the initial values based on the Lagrangian description. Finally, the semi-analytical exact solution to the cylindrical cavity expansion problem in sand is obtained by the numerical method, and the influences of the initial stress on the cavity expansion results are analyzed through an example. The results show that the particle breakage and the initial stress have great influences on the cavity stress and the radius of the plastic zone. The combination of particle breakage and initial stress causes the soil to exhibit different dilatancy characteristics during cavity expansion. In addition, the sand under high initial stresses is difficult to reach the critical state during cavity expansion.

关 键 词：柱孔扩张 颗粒破碎 拉格朗日分析法 土体初始应力 

分 类 号：TU43[建筑科学—岩土工程]