3D Geomechanical Model Test on Global Stability of Lizhou RCC Arch Dam on Muli River

摘要

Lizhou Hydropower Station is located on the Muli River,a large branch of the Yalong River.The double-curvature RCC arch dam is 132 m high which is the world-class high RCC arch dam.At the dam site,the river valley is narrow and steep with suitable topographic condition for constructing high arch dam.While some weak structural planes including faults,interlayer shear zones and fissure zones and large fissures,are developed in both abutments and affect the global stability of dam and foundation.It is necessary to be studied about this engineering issue.A 3D geomechanical model test is presented in this paper to simulate these adverse geological structures and analyze their negative impacts on stability.Through the overloading destructive experiment,the deformation characters,failure pattern and mechanism of dam,rocks and structure planes in abutment are obtained.The controlling factors and the weak regions impact the stability are revealed.And the overloading safety coefficients of dam and abutment at different destructive stages are determined as follows: K1 =1.4 ～ 2.2,K2 =3.4 ～ 4.3,K3 =6.3 ～ 6.6.The stability of dam and abutment is evaluated.Furthermore,some reinforcement measures for the weakness of dam abutment are advised.