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利用二维颗粒流程序生成5种不同粗糙程度的节理模型,并对5种节理模型进行了5种不同法向恒定荷载作用下的直剪试验,从细观角度分析了不同粗糙程度的节理模型在法向荷载下的形貌损伤情况和裂纹演化机制。与此同时,分析了节理JRC值和节理面颗粒摩擦系数对节理抗剪强度影响,并反推出了节理面抗剪强度参数Cj与j与JRC值的关系。结果为:法向恒定荷载越大时,节理峰值抗剪应力越大,剪胀现象越小,节理形貌损伤范围越大。随着剪切的进行,上下节理面接触范围减小,微裂纹开始主要沿节理面产生,随着剪切位移的继续增加微裂纹数量显著增加,并且不局限于节理面附近而深入到模型内部。随着节理粗糙程度(JRC值)和节理面颗粒摩擦系数的增加节理峰值抗剪应力也增大。节理抗剪强度参数Cj与j随着JRC值的增大而增大。所得结果可以为室内试验和工程应用提供参考和依据。
Five kinds of joint models with different roughness were generated by two-dimensional particle flow program. Five kinds of joint models were subjected to five kinds of direct shear tests under constant normal loads. The joint models with different roughness were analyzed from the microscopic point of view. MORPHOLOGICAL DAMAGE AND CRACK EVOLUTION MECHANISM UNDER NORMAL LOAD. At the same time, the influence of joint JRC value and friction coefficient of joint surface on the joint shear strength was analyzed, and the relationship between the joint shear strength parameters Cj and j and JRC value was deduced. The results are as follows: The larger the normal constant load, the larger the peak shear stress, the smaller the dilatancy phenomenon and the larger the damage area of the joint morphology. As the shear progresses, the contact area of the upper and lower joints decreases. The micro-cracks begin to occur along the joint surface. The number of micro-cracks increases with the increase of the shear displacement, and it is not limited to the vicinity of the joint surface and penetrates into the interior of the model . The joint peak shear stress increases with the increase of joint roughness (JRC value) and the friction coefficient of joint surface particles. The joint shear strength parameters Cj and j increase with the increase of JRC value. The results can provide reference and basis for indoor experiment and engineering application.