裂隙岩体等效力学参数结构效应的计算机模拟试验研究

Numerical modelling of structural effect of equivalent mechanical parameters of fractured rock mass

为研究裂隙岩体结构效应对其等效力学参数的影响,引入基于离散元的合成岩体技术,通过可控的改变三维岩体结构网络中的结构参数,制作相应的合成岩体试件,开展计算机模拟试验研究。结果表明:随岩体中裂隙体积密度增大,裂隙的变形参数和强度参数随裂隙密度增加而减少,其中等效弹性模量对结构面密度变化最为敏感;随岩体中裂隙倾角增加,岩体等效弹性模量随之单调增加,且等效弹性模量的离散程度(标准差)随倾角增加而减小,而各强度参数指标则先减少而后增加,形成一个U形变化规律;岩体等效力学参数均随结构面尺寸增加而减小,同时等效力学参数的离散程度(标准差)随结构面直径增加而增加,其中单轴抗压强度指标变化最为敏感;岩体等效力学参数对裂隙尺寸和产状的离散程度不敏感。该研究结论可为其他结构效应研究提供一种新思路。

The structural effect of fractured rock mass on equivalent mechanical parameters is studied by introducing a new synthetic rock mass technique based on the discrete element method（DEM）. Through the controllable change of structural parameters in the three-dimensional（3D） rock mass structure network, the corresponding synthetic rock specimens are produced, and numerical simulations are carried out. The results indicate that equivalent mechanical parameters decrease with the increase of fracture density. Particularly, the equivalent elastic modulus is the most sensitive to the change of fracture density. With increasing the fracture dip angle, the equivalent elastic modulus increases and its standard deviation decreases. While strength parameters decrease first and then increase to form a U shape with increasing the dip angle. The equivalent mechanical parameters decrease with the increase of fracture size. Meanwhile, their standard deviations increase with the increase of the fracture diameter, and especially the uniaxial compressive strength is the most sensitive index. Moreover, the dispersions of the fracture size and dip angle have little influence on the equivalent mechanical parameters. This study can provide certain references for studying the structural effect of the fractured rock mass on equivalent mechanical parameters.