官地水电站坝址区初始地应力场反演分析

岩体初始应力场是影响岩体变形与稳定的主要力源,也是岩土工程设计和施工中考虑的主要因素之一,尤其在高地应力地区显得尤为重要。根据官地水电站厂区的地质条件及地应力实测资料,运用有限元数值分析方法,对坝址区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;通过多方案分析论证,实测点的计算应力值与实测值在量值上和方向上均较为接近,表明反演得到的坝址区三维地应力场是合理的,符合近坝区地质构造历史背景,其成果可供工程采用。

Inversion analysis of initial geostress in dam site of Guandi Hydropower Project

The initial geostress is the main source of force influencing the deformation and stability of underground powerhouses and also one of key factors to be considered in engineering design and construction, especially in construction of underground powerhouses of large hydropower projects. Based on the geological conditions and measured geostress data of an underground powerhouse of a certain hydropower project, the finite element method is applied to analyze the initial geostress of the underground powerhouse. It is shown that the action of the horizontal geological structure is preferably dominant in the region of the underground powerhouse, and the geostress is composed of the gravitational stress and the tectonic stress. Through comparison between the calculated and measured geostresses of measuring points, it is found that these two are similar in values and directions, which suggests that the geostress field obtained by regression is reasonable and conforms to the historical background of geological structure. The results of the geostress field can be applied to practical engineering projects.