水电工程坝址区构造应力场三维数值反演

3D-Numerical Back Analysis of Tectonic Stress Field in Dam Site of Hydropower Project

以水电工程实例为背景,在现场调查和地应力测量的基础上,采用三维数值技术对水电站坝址区小范围内构造应力场进行了反演分析,通过对三维模型施加不同量值、不同方向的边界载荷,对比分析应力拟合点处的计算主应力与实测主应力之间的差别,从而得到最合理的边界载荷的量值和方向,即为坝址区构造应力场的量值和方向。计算结果表明:水电站坝址区构造应力场σ1方向为S50°-60°E,量值为6～7MPa;σ3方向为N50°-60°E,量值为3～4MPa。反演计算得到的坝址区构造应力场方向与区域应力场方向吻合,主应力量值也在合理范围内。

A back analysis for tectonic stress field in dam site of hydropower project is implemented by using three-dimensional FEM base on locale investigation and stress testing.It can be find out the reasonable numerical values and direction of boundary loads by contrasting the principal stresses between calculation and tested in-situ at the points for stress fitting by means of applying boundary loads with a different values and directions to three-dimensional model.The results from back analysis are regarded as the value and the direction of tectonic stress field in this region.The results show that the major principal stress σ1 is 6-7 MPa and its direction is S50°-60°E and minor principal stress σ3 is 3-4 MPa in direction of N50°-60°E in dam site of hydropower station.