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

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

    • 摘要: 为了解离散裂隙网络的几何参数对裂隙岩体力学参数的影响,本文构建了不同结构特征的离散裂隙网络,并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,裂隙倾角为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,而对于其他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。

       

      Abstract: In order to understand the influence of the geometric parameters of discrete fracture network on the mechanical parameters of fractured rock mass, discrete fracture networks with different structural characteristics are constructed, and the corresponding synthetic rock mass model is established.The mechanical parameters of the synthetic rock mass model are obtained through uniaxial compression numerical test, and the influence of the geometric parameters of discrete fracture network on the mechanical parameters of fractured rock mass is analyzed.The results show that with the increase of fracture density P32, uniaxial compressive strength, elastic modulus and peak strain decrease approximately linearly, and Poisson’s ratio increases approximately linearly.With the increase of the mean value of fracture dip angle, the uniaxial compressive strength, elastic modulus and peak strain first decrease and then increase, and the Poisson’s ratio first increases and then decreases.When the fracture dip angle is 60°, it reaches the extreme value.For the distribution characteristics of fracture dip angle, when the mean value of fracture dip angle is 60°, the uniaxial compressive strength, elastic modulus and peak strain decrease with the increase of Fisher distribution constant, and the Poisson’s ratio increases with the increase of Fisher distribution constant.For the mean value of other fracture dip angles, Fisher distribution constant has little effect 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 discrete fracture network and the elastic modulus is the least sensitive.

       

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