基于边界元法的岩体渗透系数尺寸效应研究

Scale effect in permeability characteristics of rock mass using boundary element method

利用Monte-Carlo法模拟生成二维裂隙网络,建立9个不同尺寸的岩体模型,结合岩体裂隙网络生成技术与边界元法,分析不同地下水孔隙压力作用下,岩体的渗透系数及其变化规律。结果表明:在岩体尺寸小于12 m时,岩体渗透系数的尺寸效应曲线不稳定,呈现波动跳跃的规律;随着岩体尺寸的逐渐增大,曲线波动逐渐衰减,趋于稳定。说明裂隙岩体的渗透系数与变形模量或强度等力学参数类似,都具有尺寸效应,且随着地下水孔隙压力的增大,岩体的渗透系数随之增加。

Based on the Monte-Carlo method,the structural plane network of jointed rock masses was generated to study the rock scale effect. Nine rock mass samples with different sizes were obtained. Combined with modeling techniques of fracture network system,the boundary element method is applied to investigate the coefficient of permeability of rock specimens under the action of a certain pore pressure of groundwater. The research shows that the scale effect curve of permeability coefficient is not stable when the size of rock mass is less than 8m; With the increase of rock mass size,the scale effect curve of permeability coefficient gradually decays. This fully shows that the permeability coefficient of rock mass has size effect. Finally,the influence of pore pressure on rock size effect is discussed. With the increase of pore pressure,the permeability coefficient of rock mass increases.