离散裂隙网络的几何参数对裂隙岩体力学参数的影响研究

构建不同结构特征的离散裂隙网络,然后建立相应的等效岩体模型,通过单轴压缩数值试验得到等效岩体模型的力学参数,分析离散裂隙网络的几何参数对裂隙岩体力学参数的影响。结果表明：随着裂隙密度P₃₂的增加,单轴抗压强度、弹性模量及峰值应变近似线性递减,泊松比近似线性递增；随着裂隙倾角均值的增加,单轴抗压强度、弹性模量及峰值应变先减小后增大,泊松比先增大后减小,在60°时达到极值；对于裂隙倾角的分布特征,当裂隙倾角均值为60°时,单轴抗压强度、弹性模量及峰值应变随Fisher分布常数的增加而减小,泊松比随Fisher分布常数的增加而增加,而对于其它裂隙倾角均值的情况,Fisher分布常数对裂隙岩体力学参数的影响较小；对于裂隙直径的分布特征,幂律分布指数对裂隙岩体力学参数的影响较小；敏感性分析结果表明,单轴抗压强度对于离散裂隙网络几何参数的敏感性最大,弹性模量的敏感性最小。

Study on the influence of geometrical parameters of discrete fracture network on mechanical parameters of fractured rock mass

To study the influence of the geometric parameters of the discrete fracture network on the mechanical parameters of the fractured rock mass, discrete fracture networks with different structural characteristics are constructed, and the corresponding synthetic rock mass models are established. The mechanical parameters of the synthetic rock mass model are obtained through uniaxial compression numerical tests. The results show that uniaxial compressive strength, elastic modulus and peak strain decrease approximately linearly with the increase of fracture density P₃₂, and Poisson"s ratio increases approximately linearly. With the increase of mean fracture dip angle, uniaxial compressive strength, elastic modulus and peak strain first decreased and then increased, and Poisson"s ratio first increased and then decreased, reaching its extreme value at 60°. For the distribution characteristics of the fracture dip angle, when the average value of the fracture dip angle is 60°, the uniaxial compressive strength, elastic modulus, and peak strain decrease with the increase of the Fisher distribution constant, and the Poisson"s ratio increases with the increase of the Fisher distribution constant. For the average value of other fracture dip angles, the Fisher distribution constant has little effect on the mechanical parameters of fractured rock mass. For the distribution characteristics of fracture diameter, the power law distribution index has little influence on the mechanical parameters of fractured rock mass. The sensitivity analysis results show that the uniaxial compressive strength is the most sensitive to the geometric parameters of the discrete fracture network and the elastic modulus is the least sensitive.