不同接触状态下粗糙节理剪切强度性质的颗粒流数值模拟和试验验证

节理表面形貌和接触状态对节理剪切力学性质有重要的影响。用砂浆材料的单轴压缩试验和光滑节理直剪试验得到材料和光滑节理的宏观力学性质参数，对颗粒流数值模拟的节理细观力学性质参数进行标定。用颗粒流离散元数值软件(PFC2D)构建人工粗糙节理表面形貌，对不同表面形貌的节理在不同接触状态下的剪切强度性质进行颗粒流直剪数值模拟试验，获得其峰值剪切强度。同时进行人工材料节理直剪试验，与颗粒流直剪数值模拟试验结果进行对比分析，数值试验与直剪试验结果吻合较好，验证了颗粒流直剪数值模拟试验与直剪试验具有同等的精度，可以作为各种表面形貌的节理在不同法向应力水平下抗剪强度研究的一种补充方法，以解决节理直剪试验中表面形貌损失对其剪切强度的影响，也可以在少量节理直剪试验的基础上，预估相同形貌的节理在不同接触状态下的剪切强度性质，同时还可以在现场测定不同粗糙度的节理表面形貌，预估其在不同接触状态、不同法向应力下的剪切力学性质。从而解决节理直剪试验中在相同形貌节理试件取样和制备困难的问题，且具有经济、方便、快捷、可重复性强等特点。

NUMERICAL SIMULATION AND TEST VALIDATION FOR DIRECT SHEAR PROPERTIES OF ROUGH JOINTS UNDER DIFFERENT CONTACT STATES

The shear behavior of rock joint is mainly influenced by its morphology and contact states. The macro- parameters of the model material are determined by uniaxial compressive tests for mortar material samples and direct shear tests of smooth joints. The meso-parameters used in particle flow code in 2 dimensions(PFC2D) simulation are calibrated by its macro-mechanical behaviors. Real rough joints model has been rebuilt by PFC2D successfully. And a series of PFC2D numerical direct shear tests have been done for joints under different morphologies and contact states，and the peak shear strength is got. Direct shear test of artificial rock joints is used to check the accuracy of the results by numerical tests. The results of numerical tests fit well with the physical experimental tests. Numerical test can be used as a supplementary method to estimate the peak shear strength of rock joints with various morphologies under different normal stress conditions. The influence of morphology degradation during the direct shear test on the peak shear strength can be solved by numerical shear tests；and the peak shear strength of joint under different contact states also can be estimated based on part of physical experimental tests. And then，the morphology of joints with different roughnesses can be measured in the field；and the peak shear strength under different contact states and different normal stresses can be predicted. The problem that sampling and preparation of joint samples with same morphology in direct shear test has been solved by the numerical method. The numerical method has the characteristics of economic，convenient，quick and effective and repeatable.