三峡水利枢纽船闸区地应力场初步分析

Preliminary Analysis of Ground Stress Field for the lock Area of Three-Gorge Project

本文以三峡工程船闸二闸室北坡300号钻孔不同测段深度的地应力实测资料为依据,通过该钻孔顺船闸轴线和垂直船闸轴线作两个计算剖面,进行有限元计算和多元线性回归,并优化回归方程。经计算分析初步认识如下:在深度150m的上部,以地质构造应力场为主导,大主应力方向为北东东向;在深度180m的下部,以自重应力场为主导,大主应力随深度线性增加,并趋干铅垂方向。地质构造应力场的主压方向,深度超过150m以下,由原来北东东向转为北北西向。该地区地应力场分析结果与实测资料、区内地质结构面、地形起伏变化的影响、坝址区断裂构造体系及其力学特性基本相符。

On the basis of the measured informations and data of ground stress of the second lock-chamher, and through calculating two sections which is parallel and perpendicular to the lock axis, the finite element analysis and multiple elements linear regression have been performed, being optimized regression equations.By means of calculations and analysises, preliminary recognitions of the ground stress field for this area are as follows: above depth 150 m, the geologic structure stress field is the main part, major principal stress is north east east in direction; below depth 180m, the dead weight stress field is the main part, major principal stress incrases lineally with depth and its direction tending to perpendicular. Below depth 150m, the main press direction of geologic structure stress turns gradually to north north-west from north-east east. These analysis results of ground stress field in this area are consistent basically with the measured informations and data in situ, the effect caused by changes of the geologic structure plane and geographical undulation, the fracture tectonic system in dam area and its mechanical properties.