柱状节理玄武岩强度各向异性特征对承压板试验结果的影响分析

Influence of Strength Anisotropy Characteristics of Column Jointed Basalt on Bearing Plate Test Results

针对现有原位试验将岩体视为均匀连续的各向同性线弹性体,应用弹性理论公式计算岩体宏观力学参数,不能反映柱状节理岩体的非连续性和强度各向异性特征问题,基于AutoCAD平台的三维地质可视化技术和计算机图形学的空间三维图形变换技术,建立了白鹤滩水电站柱状节理离散元数值模型,研究柱状节理各向异性力学特征对承压板试验结果的影响。基于刚性承压板试验数值计算结果,发现竖向承压板试验荷载与柱体接触面积小,荷载作用集中,柱状节理倾斜以及节理面切向刚度较小导致承压板边缘处柱体将沿倾斜节理面产生较大的切向变形;水平承压板试验荷载与柱体接触面积大,应力传递连续,柱状节理岩体整体承载能力较好,测得的变形模量比竖向承压板试验大。

In order to solve the problem that the rock mass is regarded as homogeneous,continuous,isotropic and linear elastic medium in the existing in-situ test,and the macro mechanical parameters of rock mass are calculated by the elastic theory formula,which cannot reflect the discontinuous and strength anisotropy characteristics of columnar jointed rock mass,the discrete element numerical test model of columnar joints in Baihetan hydropower station was established by 3D geological visualization technology of AutoCAD platform and the 3D graphics transformation technology of computer graphics to study the influence of anisotropy mechanical characteristics of columnar joints on the test results of pressure bearing plates.Based on the numerical calculation results of rigid bearing plate test,it is found that the contact area between vertical bearing plate load and the column is small and generate concentrated load.The inclination of the column joint and smaller tangential stiffness of the joint surface cause the large tangential deformation of the column at the edge of the bearing plate along the inclined joint surface;The contact area between horizontal bearing plate test load and the column is large,the stress transmission is relatively continuous so that the overall bearing capacity of the column jointed rock mass is good and the deformation modulus obtained by the test is higher than that of the vertical bearing plate test.