基于尺度律的裂隙网络生成及其对地下厂房稳定性的影响分析

Generation of fracture net based on scale law and its effect on underground powerhouse stability

以锦屏二级为工程背景,通过对猫猫滩闸址区域内断层的统计,得到断层数量与尺度的幂律关系,并通过分段线性拟合的方法估算了断层系统的尺度-数量分维发现,当断层迹长r<0.1km时,分维D=0.4875;当断层迹长r>0.1km时,分维D=1.4961。通过该尺度律关系,结合蒙特卡洛法,推演了更小规模的节理的空间分布。运用DDA数值计算程序,分析并模拟了大水沟地下厂房的开挖过程,获得了高度节理化的由开挖引起的应力、位移变化图。

Based on the Jinping second stage hydropower station, a distribution diagram of faults, is obtained from the geological diagram at Maomaotan lock site. A power-law relation between fault number and fault size is proposed, i.e. N（r） - r^-D. Two power exponents are estimated by using linear fitting in two segments. It is found that the power exponent D has a value of 0.48 if fault lengths r are shorter than 0.1 kin; while the power exponent is equal to 1.49 if fault lengths r are longer than 0.1 km. Combining with Monte Carlo method, the spatial distribution of a further small scale of joints can be obtained. Finally, the discontinuous deformation analysis （DDA） is employed to numerically simulate and analyze the excavation of the Dashuigou underground powerhouse; and the stress and displacement plots resulted from excavation in highly jointed rock mass are obtained.