基于分项系数法的重力坝深层抗滑稳定分析

针对基于有限元法的重力坝深层抗滑稳定分析问题，根据工程实际中软弱结构面上的抗剪断摩擦系数和凝聚力变异性不同的特点，在计算中引入滑动面上抗剪断强度参数的分项系数，提出了一种新的应用于重力坝抗滑稳定的有限元计算方法--分项系数有限元法。该方法基于可靠度思想，以达到用极限承载状态时的强度储备系数或超载系数来表征大坝安全度。在已有研究成果的基础上，从坝基渐进破坏过程和破坏机理的角度进一步探讨了非线性有限元法应用于深层抗滑分析应注意的几个关键问题，以及基于分项系数法的深层抗滑稳定分析的安全系数控制标准。研究结果表明，滑动面上的应力分布性态和坝基岩体变形特性对抗滑稳定安全系数有重要影响。与常规刚体极限平衡方法的控制标准相比，分项系数有限元方法可以采用偏低一点的安全系数标准。

Analysis of anti-sliding stability in deep foundation of gravity dam based on partial coefficient

In light of the different variances of friction against shearing and cohesion,a new method based on partial coefficient is proposed to apply to gravity dam stability analysis.And the corresponding stability check formula is derived.This method is based on reliability idea,and the dam final stability coefficient dam of is defined by the strength reserve coefficient or over loading coefficient at limit equilibrium state.From gradual failure progress and failure mechanism of dam foundation,further discussion is performed that several key problems should be given attention and how to define safety coefficient criterion for gravity dam stability analysis against sliding in foundation with nonlinear FEM.The research results show that stress distribution on foundation surface for gravity dams and deformation characteristic of foundation rock had an important influence on safety coefficient.The computation results of actual projects show that,compared with the conventional rigid limited balance method,safety coefficient criterion of partial coefficient FEM tends to be on the low side.