深切河谷地形下地应力场分布特征与规律

Distribution Characteristics and Laws of Ground Stress Field under Deep Valley Terrain

中国西南地区深切河谷地形下地应力场分布特征复杂,给地下洞室群稳定性分析带来巨大挑战。为研究深切河谷地形下地应力场分布规律,首先统计分析了西南地区13座大型水电站地应力实测数据,研究了主应力量值及比值随垂直埋深和水平埋深的变化规律,并将主应力方向绘制于世界应力图数据库。然后通过数值模拟方法,研究了不同河谷坡度下边坡地应力场分布特征。结果表明:主应力随垂直埋深总体呈线性增长,主应力间比值随垂直埋深增加离散程度减弱,可以用负指数函数表示。河谷谷底应力集中程度随河谷坡度增加而增大,边坡浅表部最大主应力变化剧烈,随水平埋深增加逐渐稳定。边坡最大主应力受水平埋深、垂直埋深和河谷坡度综合影响。

The complex distribution of stress field in deep valley terrain in southwest China brings great challenge to the stability of underground cavern groups.In order to study the distribution law of in-situ stress field under the deep valley terrain,the measured data of in-situ stress in thirteen large hydropower stations in southwest China are statistically analyzed,and the variation law of principal stress value and ratio with vertical and horizontal buried depths are studied.Then,the distribution characteristics of stress field under different valley slope are studied by numerical simulation.The results show that the principal stress increases linearly with vertical depth,and the ratio of principal stresses decreases with vertical depth,which can be expressed by negative exponential function.The stress concentration of the valley floor increases with the increase of the valley slope,and the maximum principal stress on the shallow side of the slope changes sharply and becomes stable with the increase of the horizontal buried depth.The maximum principal stress of the slope is affected by horizontal buried depth,vertical buried depth and valley slope.