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非贯通节理岩体的强度特性是大型边坡、隧道等工程安全性的重要影响因素。随着酸雨、河流污染等对岩石环境劣化程度的加剧,考虑环境劣化因素对非贯通节理岩体强度的影响很有必要。采用离散元法,基于已有的胶结接触模型,将岩体因环境作用而劣化等效为岩石试样质量损失不断加剧的过程,最后等效为颗粒和颗粒之间的物质不断溶蚀的过程,由此建立考虑环境劣化的微观接触模型并将其植入离散元软件中,模拟分析了不同环境劣化程度的非贯通节理岩体在不同连通率和不同法向应力下的直剪试验。结果表明:不同环境劣化程度非贯通节理岩体剪切应力-位移曲线趋势一致;随环境劣化程度的加深,节理岩体的破坏形式以拉裂纹为主转变为以剪切裂纹为主;环境劣化使得节理岩体直剪试验起裂应力降低,且环境劣化程度的加深会导致非贯通节理岩体的凝聚力降低及内摩擦角减小,表现为峰值剪切强度降低。
The strength characteristics of non-through jointed rock mass are the important factors affecting the safety of large-scale slopes and tunnels. With the exacerbation of the deterioration of rock environment caused by acid rain and river pollution, it is necessary to consider the influence of environmental degradation on the strength of non-through-jointed rock mass. Based on the existing cemented contact model, the degradation of rock mass due to environmental effects is equivalent to the process of exacerbating the loss of mass of rock sample. Finally, the process is equivalent to the continuous dissolution of the material between particles and particles, The microscopic contact model considering the environmental degradation is established and implanted into the discrete element software. The direct shear tests of the non-through jointed rock masses with different environmental degradation under different connectivity rates and different normal stresses are simulated. The results show that the trend of shear stress-displacement curves of rock mass with different degrees of environmental degradation is the same. With the deepening of environmental degradation, the failure mode of rock mass mainly changes from tensile cracking to shear cracking, and the environmental degradation As a result, the stress at initiation of jointed rock mass decreases with the increase of environmental degradation, which leads to the decrease of cohesive force and decrease of internal friction angle of non-through jointed rock mass, which shows the decrease of peak shear strength.