小湾水电站坝址区三维初始地应力场反演回归分析

Regression analysis of 3D initial geostress field for dam site of Xiaowan Hydropower Station

基于小湾水电站坝址区工程地质地形条件,研究分析了影响工程考察域初始地应力场的基本因素及其空间分布,建立了坝址区三维有限元计算模型和初始地应力场参数空间分布模型;利用大型通用有限元软件MSC.Marc和地应力实测资料,借助最小二乘法原理,以回归精度为目标函数,优化了构造挤压荷载的模拟和作用组合,实现了初始应力场空间分布模型的参数估计。计算结果表明,改进后的方法较传统方法回归精度有了较大提高,能较为合理地模拟小湾坝址区三维初始地应力场。

According to the specific geological and topographical conditions at dam site of Xiaowan Hydropower Station, fundamental influencing factors and spatial distribution of initial geostress are analyzed. The 3D FEM model and the parameters spatial distribution regression model are built. For each factor, a corresponding calculation is executed with MSC.Marc program. Taking the regression precision as the objective function, the boundary extrusion loads are optimized to simulate the field caused by horizontal compressed tectonic movements. Finally, all parameters of the regression model are estimated. The result of back regression analysis shows that the improved method is available with higher precision, and can simulate 3D initial geostress field more practically. So sa to provide a basis for further exeavating simulation of similar projeets.