不同粗糙度的节理直剪颗粒流分析

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。

Particle flow analysis of direct shear tests on joints with different roughnesses

A model of joints with five different roughnesses has been built successfully by using the particle flow code(PFC) in two-dimensions; and a series of numerical simulation direct shear tests which under 5 different constant loads have been done. We can observe the morphology damage and crack evolution mechanism of five different roughnesses joints under different constant loads from the viewpoint of mesomechanics. At the same time, the influence of JRC value and particle friction coefficient of joint on the joint shear strength is analyzed. And a joint plane shear strength parameters and relations with JRC values are back analyzed. Detailed results are as follows: normal constant load larger is, the greater the peak shear stress of joints is, the smaller the dilatancy phenomenon is, the greater the range of joints morphology injury is. With the development of shear, the surface contact area of the upper and lower joints reduced; microcracks produced along the joint surface. As the shear displacement continues to increase, the number of microcracks increase significantly, and not limited to the vicinity of the joint plane; but to enter inside the model. The peak shear stress of joints increases with the increase of joint roughness (JRC value) and the particle frictional coefficient of the joints. Joint shear strength parameters Cj and ?j increase with the increase of the JRC value. The results can provide reference and basis for the indoor tests and engineering applications.