基于Weibull分布的非均质隧洞围岩破裂碎胀FDEM数值模拟研究  

FDEM NUMERICAL STUDY ON THE FRACTURE AND SWELLING DEFORMATION OF HETEROGENEOUS ROCK MASS AROUND TUNNEL BASED ON WEIBULL DISTRIBUTION

作　　者：邓鹏海 刘泉声[1] 黄兴[2] DENG Peng-hai;LIU Quan-sheng;HUANG Xing(School of Civil Engineering,Wuhan University,Wuhan,Hubei 430072,China;Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]中国科学院武汉岩土力学研究所,湖北武汉430071

出　　处：《工程力学》2024年第7期40-59,共20页Engineering Mechanics

基　　金：国家自然科学基金项目(41941018,U21A20153)。

摘　　要：岩石材料具有非均质特征,矿物颗粒和胶结材料强度在统计学上服从Weibull分布。基于有限元-离散元耦合数值模拟方法(FDEM)提出了三角形单元弹性模量和四边形节理单元强度服从Weibull分布的参数赋值流程,随后研究了非均质岩样在单轴压缩、三轴压缩和巴西劈裂下的力学特征和破坏行为,最后对非均质隧洞围岩在高应力下的破裂碎胀大变形机制进行了模拟研究。结果表明:提出的随机参数赋值方法可建立不同弹性模量三角形单元数目服从Weibull分布、且空间分布具有随机性的FDEM数值模型;非均质岩样单轴抗压强度、三轴抗压强度、巴西劈裂抗拉强度、等效粘聚力和等效内摩擦角随着非均质度m的增大,均呈指数增大,并向均质材料逼近;高应力非均质隧洞围岩随着m的增大,裂隙网络形态变化不大,均以共轭剪切破裂为主,并伴随少量拉伸裂隙,但围岩破坏程度和裂隙扩展范围呈指数降低。Rock materials are heterogeneous,and the strength of mineral particles and cementitious materials obey Weibull distribution statistically.Based on the combined finite-discrete element numerical method(FDEM),the parameter assignment process of elastic modulus and strength which obey to Weibull distribution is proposed.Then,the mechanical characteristics and failure behavior of heterogeneous rock samples under uniaxial compression,triaxial compression and Brazilian splitting are studied.Finally,the fracture and swelling deformation mechanism of heterogeneous rock mass around tunnel with high in-situ stress is investigated.The results show that:The FDEM numerical model,the number of triangular element with different elastic modulus obeys Weibull distribution,can be built by using the random parameter assignment method proposed in this paper;The uniaxial compressive strength,triaxial compressive strength,Brazilian splitting tensile strength,equivalent cohesion and equivalent internal friction angle of heterogeneous rock samples increase exponentially with the increase of heterogeneity m,and then approach to homogeneous materials;With the increase of m,the shape of fracture network changes little,mainly conjugate shear fracture,accompanied by a small number of tensile fractures,however,the failure degree of surrounding rock mass and the fracture propagation range decreases exponentially.

关 键 词：非均质岩体 WEIBULL分布 FDEM 破裂碎胀变形 非均质度 隧洞围岩 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]