五一水库联合进水口高边坡抗滑稳定分析

Anti-slide Stability Analysis of High Bank at the Joint Intake of Wuyi Reservoir

为调查分析五一水库联合进水口边坡的整体稳定性与局部稳定性,首先根据进水口边坡的地形地貌特征、地层岩性等,对进水口边坡的稳定性进行定性分析评价,并确定其可能的失稳模式,其次根据进水口边坡岩体产状与边坡产状的关系以及可能的失稳模式等特点,将进水口边坡分为正面坡、左侧坡、右侧坡三个子区。并在三个子区选取具代表性的剖面,采用二维极限平衡方法,对进水口边坡各工况条件下不同滑移模式的稳定状况进行定量分析计算。计算结果显示:除进水口正面坡在施工期整体滑动(由坡顶至坡脚剪出)滑移模式的安全系数较小、有发生浅层滑动失稳的可能外,其它各边坡计算剖面各工况下的安全系数均满足规范要求。由于边坡在水库蓄水后大部分位于库水位以下,在水的作用下岩土体软化,其局部部位存在发生浅层滑塌失稳可能,建议加强施工、蓄水和运行期间边坡的变形观测,并采取相应的支护措施。

In order to investigate and analyze the partial and whole stability of the bank at the joint intake of Wuyi reservoir, at first, an evaluation and qualitative analysis of slope stability was carried out according to the topography features and formation lithology of the slope, to determine its possible instability mode. Then according to the relation between oeeurance of the rock mass and the slope after excavation at the joint intake, and the possible unstable mode, to divide the slope at the joint intake into three regions： the positive slope, the left slope, and the right slope. By selecting representative section and using 2D limit-equilibrium method, a quantitative analysis and calculation was carried out on slope stability with different sliding patterns under different working conditions. The result of calculation is ： only for the positive slope, the factor of safety to the whole slip mode （ cut out from the top to the toe of a slope） during construction period is smaller, and the shallow sliding is possible. The factors of safety of all other slopes meet the requirements of specifications even in different working conditions. Because most of the slope is below the water level when the reservoir is filled, the rock will be softened under the water, the shallow slide may occur somewhere. It is suggested to observe deformation of the slope during construction after impoundment and running period, and take corresponding supporting measures.