考虑水软化作用的非贯通共面节理岩体直剪试验的离散元分析

水软化作用会使得岩体内的胶结物溶解、腐蚀，引起节理岩体宏观力学特性的劣化。为探究水软化作用对节理岩体力学特性的影响机理，本文将考虑水软化、化学风化因素的岩石微观胶结接触模型引入到离散元中并模拟了非贯通共面节理岩体的直剪试验，根据得到的剪应力-应变曲线、胶结破坏数-位移曲线以及破坏后的微观信息，从宏微观角度分析了不同饱和度下法向应力及节理连通率对节理岩体力学性质的影响。模拟结果表明：在同一饱和度时，节理岩体的峰值剪应力与法向应力的关系满足摩尔库伦定律，饱和度的增长对岩体剪切强度的影响主要是使节理面及岩桥的黏聚力降低。节理岩体的破坏以岩桥与节理面的贯通为标志，在岩桥区域产生张裂缝及贯通的剪切裂缝，且拉力链主要集中在岩桥区域。

DEM analysis on direct shear test of rock with coplanar non-penetrating joints considering water softening

Water softening process can dissolve and corrode the cementation in rock mass, and thus de-grade the macro-mechanical behavior of jointed rock. In order to investigate the mechanism of water soften-ing, the DEM simulation of direct shear test is carried out, with the use of microscopic rock bond contact model considering the influence of water softening and chemical weathering,on rock with coplanar non-pen-etrating joints. According to the shear stress-strain curve, bond breakage number-shear displacement curve and microscopic information after rock destruction, the effect of normal stress and joint connectivity on me-chanical behavior of jointed rock in different saturation is analyzed from the macro and micro perspectives. The simulation results show that the relation of peak shear stress and normal stress meets Mohr-coulomb''s law under the same saturation, and the increase of saturation can decrease the cohesion of jointed surface and rock bridge, and hence affect the shear strength of rock. Moreover, the destruction of jointed rock is marked by the connection of rock bridge. The tension crack and connected shear crack are generated in the rock bridge region,and the tensile force chain is distributed intensively in rock bridge.