复杂的结构面是控制岩体力学性质的主要因素,由结构面引起的岩体各向异性一直是岩体力学研究的热点问题。柱状节理是一类特殊的岩体地质结构面,具有强烈的各向异性特性,微结构张量理论是目前国际岩石力学领域一种较有效地探讨结构面各向异性问题的新方法。材料的微结构张量和加载向量是微结构张量法描述的两个重要参量。采用多组节理面局部坐标系与整体坐标系的投影关系,定义了材料的微结构张量计算方法,引入各向异性参数ψ表述微结构张量在加载方向的投影,将其引入Jaeger针对岩体沿节理面滑动破裂提出的基于Mohr-Coulomb强度准则,得到了多组节理岩体的各向异性强度准则。同时,结合白鹤滩坝址区的柱状节理特性,分析柱状节理引起的各向异性对坝址区稳定性的影响。
Complicated material fabrics are the main factors to control the mechanical characteristics of rock mass;currently the anisotropic problems caused by structural planes are the most hot topics.As a special structure rock mass,the discontinuity and anisotropy of rock mass with columnar joints is very typical.The microstructure can be represented by a second order tensor whose eigenvectors specify the orientation of the axes of material symmetry,which is an effective new method to study structure plane caused anisotropy.Microstructure tensor and loading direction are important parameters for this theory.With projection relation of multiple joint surface between spatial local coordinate system and integral coordinate system considered,microstructure tensor is derived.Using ψ describes the projection of the microstructure tensor on the loading direction.The modified anisotropic failure criterion,which incorporating a microstructure for columnar joints based on Jaeger proposed for failure along the material fabrics,is used to study anisotropy of the multiple joint surface.Meanwhile,we use it to consider the Baihetan hydropower station columnar joint-project and analyze columnar joint anisotropy caused stability problem.