Page - 733 - in Book of Full Papers - Symposium Hydro Engineering

COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIÈME CONGRÈS DES GRANDS BARRAGES Autriche, juillet 2018 ------- EXPERIMENTAL STUDY ON THE GLOBAL STABILITY OF THE XIAOWAN ARCH DAM USING A 3D GEO-MECHANICAL MODEL TEST J. H. DONG, L. ZHANG, B. Q. YANG, J. Y. CHEN, and Y. CHEN COLLEGE OF WATER RESOURCES & HYDROPOWER ENGINEERING, SICHUAN UNIVERSITY, CHENGDU 610065 China 1. INTRODUCTION This study constructed a three-dimensional (3D) geo-mechanical model for the Xiaowan high arch dam, which simulated the topographical and geological features, the distribution of weak structural planes, the shallow relaxation unloading phenomena, and the dam reinforcement scheme. During the test, traditional model materials were used to simulate the dam body, the concrete reinforcement plug, and the mail rock mass of the abutment and foundation, whereas temperature-analogue materials were used to simulate faults F11, F10, F5, F12, F19, and F20. A small specially prepared rhombic block and thin block were used to simulate the shallow layer of the unloading rock body. The failure test was performed using the comprehensive method, which considers both the overloading and strength-reduction techniques. 2. METHODS The combined overloading and strength reduction methods were applied in this test. The model failure test procedure is as follows. First, the model was pre- loaded and then the normal load level was applied. Afterward, the shear strength of the abutment rock faults, such as F11, F10, and F5, were reduced by approximately 20% by heating up the model materials. Finally, the overloading test was implemented until the dam instability caused the destruction of the dam abutment. The loads were applied successively in the following order as factors of the normal working load, P0: 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.3, and 3.5. 733