Experimental Study on the Global Stability of the xiaowan Arch Dam Using a 3D Geo-mechanical Model Test

Abstract

In this paper, a three-dimensional geo-mechanical model test for the Xiaowan high arch dam was studied and the topographical and geological features, the distribution of weak structural planes, the shallow relaxation unloading phenomena were simulated. Furthermore, a type of model material known as the temperature analogous material, whose strength varies with temperature throughout the experiment, was used to simulate the decrease in shear strength of the weak structural planes. The deformation characteristics and failure mechanism of the dam foundation and abutments were obtained by using comprehensive test method, which considered both the overloading and strength-reduction techniques. Through data analysis, the strength reserve coefficient, the overloading and the global safety factor were obtained. Synthetic analysis of the test results indicates that the displacement of the mid-upper abutment was reduced and the failure zone become smaller due to the significant reinforcement effects of concrete displacement plugs on the faults and alteration zones. The failure pattern shown in the model test indicates that reinforcements should be installed at faults F11 and F10 above an elevation of 1245 m in the right abutment and the rock above the thrust block in the left abutment.