木里河立洲拱坝坝肩稳定三维地质力学模型破坏试验研究

Study on abutment stability of Lizhou arch dam by failure test on three-dimensional geomechanical model

立洲水电站拱坝为高碾压混凝土拱坝,坝址区河谷狭窄具备修建高拱坝的优越条件,但地质构造较复杂,坝肩抗力体内部存在断层、层间剪切带及长大裂隙等不良地质构造,直接影响到拱坝坝肩的稳定安全性,须要开展坝肩稳定问题深入研究。针对上述地质问题,本文采用三维地质力学模型试验方法,全面模拟坝址区的不连续岩体条件、断层、层间剪切带、裂隙等主要地质缺陷,通过破坏试验,研究拱坝与坝肩的变形分布特性,揭示破坏机理与破坏形态,提出超载法试验安全系数,并针对坝肩薄弱环节提出加固处理措施意见。

The geological conditions at the site of Lizhou RCC arch dam are extremely complicated, and the abutment rock masses are featured with various unfavorable structures, such as faults, interlayer shear zones and large-scale discontinuities. These structures lower the stability of the abutments and an in-depth examination on the stability is required to ensure dam safety. This paper presents an experimental study of abutment stability using a three-dimensional geomeehanical model of topographic and geological similarity. A comprehensive series of failure tests in combination of overloading techniques reveal the features of deformation distributions and failure patterns. The failure mechanism of the abutments is analyzed and a comprehensive safety factor is determined. Engineering measures for reinforced weak regions of abutments are suggested.