锦屏二级水电站是雅砻江干流上重要的梯级电站。电站厂址区域山体雄伟,地形陡倾,为一个典型“V”型河谷地貌。受印支、燕山和喜马拉雅等区域构造运动作用,该区域地层中赋存有较大的构造应力,而新生代以来的雅砻江侵蚀下切作用又使得地层中的构造应力得到一定程度的释放。为全面研究内外动力地质作用对厂址区域现今地应力场的影响并获得该区域地应力分布,提出结合地层剥蚀模拟、弹塑性计算和进化神经网络的地应力非线性反演方法。该方法一定程度上考虑了远古构造的先后顺序,并可模拟了河流侵蚀下切过程对现今应力场的影响。将地应力的实测值与反演值对比、现场洞室围岩破坏特征两方面分析都表明该方法具有较好的可靠性。
Jinping Ⅱ Hydropower Station is an important cascade hydropower station on the Yalong River in Sichuan Province. The hydropower station region is a typical V-shaped river valley morphology with high grand mountain and deep gorge. Tectogenetic movements, including Indo-China movement, Yanshan movement and Himalayan movement, made the region preserve much horizontal constitution stress. But, the corrosion effect of the Yalong River leads to figure the V-shaped valley and release of constitution stress. For understanding the function of inter dynamical geological process and outer dynamical geological process to current geostress, a new nonlinear initial geostress back analysis method is presented, which integrates the ground abrasion simulation, elastoplastic calculation and neural network inversion. The method takes the constitution order process into account to some extent by elastoplastic calculation and simulates the ground abrasion process by surface excavation. The model is verified by two ways. One is the comparison between measured stress, and inversed stress in the same position; the other is the broken behavior of cavern rock. The results indicate that the method is reasonable.