粗粒土应力腐蚀蠕变影响因素的离散元分析

Influencing Factors Analysis of Stress Corrosion Creep for Coarse-grained Soils Based on Discrete Element Method

为探寻细观参数对蠕变的影响规律,基于应力腐蚀理论,编写了考虑颗粒破碎的粗粒土蠕变的PFC5.0应力腐蚀程序命令流,探讨了接触模型和应力腐蚀模型细观参数对蠕变的影响规律及其敏感性,并基于室内蠕变试验结果进行了参数标定。结果表明:接触模型参数中,颗粒摩擦系数和胶结键粘结强度敏感性较强,颗粒刚度和密度敏感性较差,粗粒土颗粒表面摩擦和抗拉强度越大蠕应变越小;应力腐蚀模型中,激活应力对粗粒土的蠕变有显著影响,随着激活应力的增大,颗粒破碎量急剧减少,蠕应变减小;材料参数β1和β2均对粗粒土蠕变有较大影响,蠕应变随着β1和β2的增大而增大。基于应力腐蚀理论进行考虑颗粒破碎的粗粒土蠕变的离散元分析是可行的,标定的模型细观参数可作为粗粒土颗粒破碎蠕变机理进一步研究的基础。

Based on the theory of stress corrosion,the command flow on creep was prepared for the coarse-grained soil considering particle breakage in PFC 5.0 program.The influences of the meso-parameter parameters of the contact model and the stress corrosion model on the creep behavior were analyzed.Meanwhile,the parameter sensitivity was discussed.The meso-parameters were also calibrated according to the results of laboratory tests.The results show that the particle friction coefficient and bond strength in contact model are sensitive.On the contrary,the particle stiffness and the density sensitivity are not sensitive.The greater the surface friction and tensile strength are,the less the creep strain is.In the stress corrosion model,the activation stress has significant effects on the creep of coarse-grained soil.The particle breakage decreases sharply and the creep strain decreases with the increase in the activation stress.The creep strain of coarse-grained soil was affected by the material parametersβ1 andβ2 apparently,it will increase with the increase ofβ1 andβ2.The discrete element method can be used to study creep caused by stress corrosion for coarsegrained soil considering particle breakage.The calibrated model meso-parameters can be used for further research on the creep mechanism of coarse-grained soil.