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本文介绍了长江三峡工程库首区实测地应力变化特点,分析了实测地应力中最大水平主应力(σ_(Hmax))方位随测深有规律地逆时针旋转,是由岩体自重应力(σ_v)引起的围限压应力随测深发生改变、岩体边界条件发生变化、地球自转引起的离心惯性力及其在深度上的变化等共同作用的结果;当σ_v≥σ_(Hmax)时,地应力场最大水平主应力方位趋于稳定,且最终趋于和地球自转引起的纬向惯性力方位基本一致;长江三峡工程库首区构造应力场最大水平主应力方位为北东(NE)向,地应力场最大水平主应力方位为北西西(NWW)向.
This paper introduces the characteristics of measured ground stress in the first area of the Three Gorges Reservoir, and analyzes that the maximum horizontal principal stress (σ_ (Hmax)) of the measured ground stress rotates counterclockwise with sounding depth and is composed of the self-weight stress of rock mass (σ_v ), The result of the interaction of the confining compressive stress with depth sounding, the change of boundary conditions of rock mass, the centrifugal inertial force caused by the Earth’s rotation and its change in depth, etc. Whenσ_v≥σ_ (Hmax) The direction of the principal stress at the maximum level of stress field tends to be stable and eventually approaches the azimuthal inertial force azimuth caused by the Earth’s rotation. The maximum principal stress direction of the tectonic stress field in the head area of the Three Gorges Reservoir is northeast (NE) The maximum horizontal principal stress of the geostress field is NWW.