隧道力学状态离散元模拟中的粒径效应  

Particle Size Effect of Tunnel Mechanical State in Discrete Element Simulation

作　　者：薄英鋆 王华宁[2] 蒋明镜[1,3,4] 车纳 Bo Yingjun;Wang Huaning;Jiang Mingjing;Che Na(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,P.R.China;School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,P.R.China;Department of Civil Engineering,School of Civil Engineering,Tianjin University,Tianjin 300350,P.R.China;State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300350,P.R.China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学航空航天与力学学院,上海200092 [3]天津大学建筑工程学院土木工程系,天津300350 [4]天津大学水利工程仿真与安全国家重点实验室,天津300350

出　　处：《地下空间与工程学报》2022年第5期1471-1480,共10页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金项目(11872281,51639008);同济大学土木工程防灾国家重点实验室自主课题(SLDRCE19-A-06)。

摘　　要：对于工程尺度的离散元隧道模型,颗粒尺寸是决定模型计算准确性以及效率的重要参数。引入隧道直径与平均粒径之比(特征长度比R_(a)=D/D_(50))度量颗粒的相对尺寸,研究不同工况下相对粒径对离散元模型中应力、位移以及胶结破坏的影响。通过离散元结果与解析解对比和胶结破坏率分析,给出可获得高精度模拟结果的特征长度比范围。结果表明:无胶结破坏时,离散元径向应力误差略大于环向应力误差;相比于等压情况,不等压情况下平均位移误差将增大,当R_(a)>35,离散元应力、位移与解析解误差将收敛至10%以内;发生胶结破坏时,破坏域范围达到稳定;对测量圆大小的分析显示,当圆内颗粒数目大于150左右时可以有效减小相对粒径较大时的应力误差。For the engineering-scaled tunnel model simulated by discrete element method(DEM),particle size is a key factor affecting the computational accuracy and efficiency.The ratio of tunnel diameter to average particle size(characteristic length ratio R_(a)=D/D_(50))is introduced to represent the relative particle size.The influences of relative particle size on stress,displacement and the bond failure within the model are investigated under different load cases.By comparing the DEM results with analytical solutions and investigating the bond failure rate,the range of characteristic length ratio that can obtain high-precision simulation results is obtained.The results indicate that the stress difference between DEM results and analytical solution in radial direction is slightly larger than that in hoop direction in the cases without bond failure.The average displacement difference between the two models is larger under non-hydrostatic initial stresses than that under hydrostatic ones.When R_(a)>35,the difference of stress and displacement between DEM results and analytical solution converges to within 10%,and the size of the failure zone reaches stability in the cases with bond breakage.The analysis of the size of measurement circle shows that the stress deviation of DEM result in the cases with large relative particle size can be effectively reduced when the particle number in the circle is greater than 150.

关 键 词：离散元 粒径效应 隧道 特征长度比 岩石模型 

分 类 号：TU43[建筑科学—岩土工程]