基于UDEC岩体抗压强度尺寸效应的数值研究

Numerical Simulation on Compressive Strength Size Effect of Rock Mass Based on UDEC

利用分形理论,结合Monte Carlo方法生成用于数值实验的节理岩体网络图,选取用于数值实验的节理岩体试件,通过离散元软件UDEC模拟不同围压、不同尺寸数值实验试件的抗压强度,对2组正交节理岩体抗压强度随围压和尺度的变化规律进行了研究。研究表明:随着围压的增大,节理岩体试件的抗压强度也随之增大,抗压强度随围压的变化规律呈线性变化趋势,可拟合为线性变化关系;围压作用下,节理岩体抗压强度仍然具有明显的尺寸效应,但随着围压的增大,尺寸效应有一定的削弱,但不明显;随着试件尺寸的增大,节理岩体试件的抗压强度随之减小,抗压强度随尺寸的变化规律呈非线性变化趋势,可拟合为负指数变化关系。并从理论上讨论了提出的数学关系的合理性。

The jointed rock network diagram used in the numerical experiment was generated by the fractal theory and Monte Carlo method,as well as selection of the numerical experimental conditions. And then,compressive strength changing with the confining pressure and scale of two sets of orthogonal joint rock is studied through the numerical simulation software UDEC. Researches’ results are as follows. With the increase of confining pressure,compressive strength of the jointed rock specimens increases. Furthermore,the compressive strength change with the changing rule of the confining pressure is linear trend,which can be fitted for the linear relation. Under the influence of confining pressure,the jointed rock compressive strength has obvious size effect. However,with the increase of confining pressure,size effect has an inconspicuous weakening. With the increase of specimen size,the compressive strength of the jointed rock specimens decreases,change tendency of the compressive strength changing with the size is nonlinear,which can be fitted for negative exponential relation. And the rationality of the proposing mathematical relationships is theoretically discussed.