大型水电站厂区三维地应力场回归反演分析

岩体初始地应力场是地下洞室围岩稳定与支护结构设计所需要的基本因素之一,初始地应力场是否可靠将直接影响到工程设计与施工的可靠性与安全性.结合某水电站厂区的地质条件及地应力实测资料,引入灰色控制系统理论,采用三维有限元法和采用静态的三因素灰色计算模型GM(0, 3)对厂区岩体初始应力场进行回归反演分析.计算结果表明,厂区存在较大的水平向地质构造作用,岩体的地应力由自重和构造应力叠加而成.实测点的计算应力值与实测值在量值上和方向上都较为接近,表明经过回归得到的地应力场是合理的,从而获得地下厂房厂区初始应力场较为合理的分布规律,为地下厂房的开挖模拟及稳定性分析提供了合理的初始应力场.

Regression analysis of 3D initial geostress in region of underground powerhouse for large hydropower station

Initial geostress is one of main factors used for analyzing stability of surrounding rock and design of support structures in underground caverns, and whether the company is dependable will directly affect the reliability and safety during engineering design and construction. Based on engineering geological conditions and measured geostress data in region of underground powerhouse of a certain hydropower project, grey control system theory is introduced, and finite element method as well as static three-factor grey calculation model, GM(0,3), are applied to analyze the initial geostress in region of underground caverns. Computing results show that the horizontal geologic structure action is preferably dominant in region of underground powerhouse; and geostress is composed of gravitational stress and tectonic stress. Through comparison between computed and measured geostress values of measuring points, it is shown that the two are similar in values and directions; so that the accuracy and reasonability of the geostress field regression are validated. Thereby, the distribution tendency of initial geostress field of underground powerhouse region can be obtained, so as to provide a rational 3D initial geostress field for excavating simulation and stability analysis of underground powerhouse at a certain hydropower station.