《混凝土重力坝设计规范》(NB/T 35026—2014)给出的多滑面深层抗滑稳定计算方法,以条块抗力ΔQ_i满足内力平衡条件求解抗力作用比η。由于ΔQ_i与水平向的夹角φ_i各不相同,规范方法进行ΔQ_i的标量求和没有物理意义,未能真正满足内力矢量平衡。因此,规范方法理论体系不严谨,在φ_i不相等时求解结果可能是错误的。鉴于规范方法的不足,以条块之间的剪力Q_i替换ΔQ_i,对规范公式进行修正,并提出基于单变量η的迭代求解方法,解决了规范存在的问题,提高了多滑面稳定计算的实用价值。通过典型算例和工程实例,进一步验证了规范方法的不严谨可能导致不可接受的计算错误,同时证明了文中提出的优化方法的准确性和实用性。

In Design code for concrete gravity dam (NB/T 35026-2014) of China, the method for anti-sliding stability with multiple sliding surfaces gives the solution of resistance-action ratio η based on the prerequisite that resistance ΔQ_i of sliding blocks meets internal force equilibrium. However, as the angles between ΔQ_i and horizontal direction are different, the method in the code is of no physical significance, hence could not really meet the balance of internal force vectors. In this paper, we demonstrates that the theoretical system of the method in the code is not rigorous, which might give rise to wrong result when the values of φ_i are not equal. In view of this, we optimized the method by replacing ΔQ_i with shear force Q_i between blocks, and proposed an iterative solution based on single variable η. Through typical examples and engineering applications, we further verified that the imprecision of the standard method may lead to unacceptable calculation errors; and at the same time, we proved the accuracy and practicability of the proposed method in this paper.