Abstract
The Jinping I high arch dam in China, with 305 m dam height, is the highest arch dam of the world at present. The overall stability of the dam and foundation is a protuberant problem due to the complex geological conditions at the dam site area and the weakening effect of the dam abutment weak structural planes when the project put into operation. In this paper, firstly, the weakening effect experimental research was carried out under the coupling interaction of stress field and seepage field. Through the test, the weakening rates of the strength parameters of the weak structural planes were obtained. Secondly, the three-dimensional geo-mechanical model comprehensive method test was carried out under reinforced foundation conditions. In the experiment, the integrated strength decreased range of weak structural plane was determined as 30% according to the weakening effect experimental results, and the temperature analogous materials were developed to simulate the weakening effect. Through the test, the deformation characteristics and failure mechanisms of the dam and dam abutment were obtained. And the overall stability safety factors were determined as 5.2~6.0. The research results provide an important scientific basis for the design, construction and safe operation of the project.
1. INTRODUCTION
2 class soft rock and the green schist lens develops in the marble strata are also have the characteristic of decrease the mechanical parameters under the influence of water. After the impounding and operation of the high arch dam project, the mechanical properties of these weak rock masses and weak structural planes will be changed greatly. So that the strength weakening behavior has a serious impact on the stability and safety of the Jinping I high arch dam and foundation, and these weak structural planes combine with high ground stress, high earthquake intensities and high hydraulic thrust will definitely control the stability of Jinping I Project. How to quantitatively reveal the weakening effect under thousands of tons of water load and long-term effect of complexity seepage field after the project put into operation, as well as to reasonably reconsider the weakening effect in evaluating the overall stability of high arch dam and foundation is a very important research subject.
