基于修正模型数值计算结果的等K法改进

Modification of equal K value method based on simulation results of modified model

等K法是校核双滑面坝基深层抗滑稳定性问题的主要方法。实际操作中,不同的取值方法对安全系数结果影响很大。现有的取值方法或根据以往的工程经验,或直接参照有限元计算成果进行取值,缺乏严格的理论基础,其合理性、使用范围有待详细判定。研究发现:①对双滑面问题,直接对滑面进行模拟得到的应力结果不宜用于刚体极限平衡法,必须对滑动面进行修正;②刚体极限平衡法中滑动力代数之和,与采用修正滑面的有限元强度折减法极限状态滑动面上剪应力叠加之和相等,并应在此基础上对安全系数及抗力角进行求解。

Value - taking for resist angle has significant influence on calculated safety factors when rigid body limit equilibrium method is adopted in checking anti - sliding stability on dam base. The existing methods are based on engineering experiences or referring to results of FEM calculation, which are lack of theoretical basis. And their rationality and range of use are still questionable. We find that referring to results of FEM calculation directly is inappropriate. We propose the FEM sliding surface shall be modified and algebraic sum of sliding force based on rigid body limit equilibrium method is equal to superposition of shear stresses on the sliding surfaces in limit state using limited strength reduction method with modified sliding surface, as a result, we can find the solution on safety factors and resist angles.