Page - 734 - in Book of Full Papers - Symposium Hydro Engineering

3. RESULTS The asymmetry of the two-bank terrain and the geological condition of the dam abutments created an asymmetric trend of the displacement of the dam body. In the overloading stage, with an increase in overloading multiples, the displacement of the dam body continuously increased and had an asymmetric trend, which indicates that the displacement of the right arch abutment was slightly larger than that of the left arch abutment. Under normal working conditions, the surface displacement of the abutments and resistance blocks of both the left and right banks was minimal, and there was no abnormal phenomenon. After Kp was increased to over 3.0, the surface displacements of both abutments increased rapidly and the change amplitude of the displacement curve increased. Furthermore, the measuring points near and around the arch abutment and at the fault outcropped points had abruptly increasing displacement and fluctuating displacement curves. The primary reasons for the failure of the arch dam and foundation plane are as follows: in the later portion of the overload period, especially when the overloading coefficient Kp was over 3.0, the load born by the arch dam was large, and the geological condition of the two abutments had a large asymmetrical phenomenon. Furthermore, the resistance bodies of the two abutments had inhomogeneous deformation, and the width height of the river valley in the dam area was large. The beam direction effect of the arch dam was large, which caused fissures in the dam body and foundation plane. Based on the analysis of the experimental data and results, the strength reserve coefficient K1 is 1.2 and the overloading safety factor K2was estimated to be 3.3-3.5, respectively, that is, 2.4~96.3)5.3~3.3(2.121      KKKC Thus, the global safety factor KC for the Xiaowan Arch Dam and foundation should be 3.96-4.2, which meets the present design requirement. REFERENCES [1] J. H. DONG, H. P. XIE AND L. ZHANG, Experimental study on 3D geomechanical model for global stability analysis of Dagangshan double curvature arch dam, Chin. J. Rock Mech. Eng. 26 (2007) 2027-2033 (in Chinese). [2] D. F. MARTT, A. SHAKOOR AND B. H. GREENE, Austin Dam, Pennsylvania: The sliding failure of a concrete gravity dam, Environ. Eng. Geosci. 11 (2005) 61-72. [3] E. ITOYA, Y. ZHAO AND Y. O. MARTINS, Stability analysis of a concrete gravity dam and its foundation, J. Southeast Univ. (English Edition) 20 (2004) 508-512. [4] W. P. FEI, L. ZHANG AND R. ZHANG, Experiment study on a geo- mechanical model of a high arch dam, Int. J. Rock Mech. Mining Sci. 47 (2010) 299-306. 734