锦屏一级高拱坝整体稳定物理与数值模拟综合分析

高拱坝的整体稳定是工程建设中的关键问题之一,地质力学模型试验和数值计算是研究这一问题的重要方法。通过理论推导建立了基于综合法的大坝稳定安全系数评定关系式。针对锦屏一级高拱坝坝肩地质条件复杂,影响拱坝整体稳定的断层、岩脉、节理裂隙众多,坝高库大和加固难度大,工程安全稳定问题十分突出等特点,采用综合法地质力学模型试验与三维非线性有限元相结合的方法,对加固处理后的锦屏一级高拱坝整体稳定性开展研究。获得了拱坝在正常工况下的工作性态,以及在结构面强度参数降低约30%后坝肩的超载变形失稳过程和最终破坏形态,提出拱坝与地基综合法整体稳定安全度为5.2~6.0(试验值)和5.98(计算值)。通过综合分析模型试验和数值计算的成果,评价了锦屏一级高拱坝工程的安全性和加固效果。研究成果为锦屏一级拱坝工程的安全监测和运行管理提供了科学依据,同时也为其他类似高拱坝工程的稳定分析提供参考。

Experimental and numerical comprehensive analysis on overall stability of Jinping I high arch dam

The overall stability of the high arch dam is one of the key issues in construction of the project. Geo-mechanical model test and numerical calculation are the main methods to study this issue. Jinping I high arch dam is featured with complicated geologic structures of various types of faults, dykes, joints and fissures, and its overall stability is greatly influenced by these structures. It has great dam height and huge capacity of the reservoir,and the reinforcement was difficult. In this paper,firstly,the evaluation basis for the safety factor of dam stability is established based on the comprehensive method. Than adopted the methods of 3D geo-mechanical model test and 3D nonlinear FEM calculation to study the overall stability of Jinping I high arch dam under the condition of reinforced foundation. The workability of the arch dam under normal conditions, and the deformation characteristics, failure patterns and mechanisms of the dam abutment and foundation are obtained. The analysis shows that the overall stability of safety coefficient is 5.2~6.0 by comprehensive model test and 5.98 by comprehensive FEM computation. The overall stability of Jinping I high arch dam is evaluated synthetically by combining the results of the two methods. The research results provide an important scientific basis for monitoring and safe operation of the project. It also can provide a reference for the stability analysis of other high arch dams.