水电站尾水出口边坡平面有限元分析

Plain Finite Element Analysis to the Slope at Tail Water Outlet of Hydro-power Station

采用平面有限元方法模拟某水电站尾水出口边坡开挖、支护条件下的应力、变形特征,分析锚索的加固效果、节理和水位上升等因素对边坡变形及稳定性的影响,并给出了水位上升条件下边坡塑性破坏区增大的力学解释。最后由基于Mohr-Coulomb屈服准则的弹塑性有限元的强度折减方法计算得到边坡的安全系数,对尾水出口边坡的整体稳定性进行评价,结果表明:加固后的边坡在最不利的条件下(水位上升10 m)的安全系数大于1.25,边坡处于稳定状态。

By using the plain finite element method, the excavation of slope at tail water outlet, the stress and deformation properties under the supporting condition are simulated at the hydro-power station. Then factors, influencing the deformation and stability of slope, are analyzed, such as the effect of the anchor cable for reinforcement, the joint, the rising at the level of water and so on, and the mechanical explanation to the problem that the higher the level of water, the larger the plastic zone of slope is given. Finally, the safety factor of slope is calculated by the strength reduction method based on the elastic-plastic finite element of Mohr-Coulomb yield criterion and the stability of slope at tail water outlet is evaluated. From the results it is show that the slope is stable under the worst case that the safety factor of slope is above 1.25, which the level of water is up to 10.0 m.