Analysis of distribution law of in-situ stress field in asymmetric valley of Baihetan Dam site
LIN Taiqing;RONG Guan;XU Hailiang;HU Yang;YIN Penghai;State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University;Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering,Ministry of Education;
To discuss the evolution laws of in- situ stress field at Baihetan Dam site,the evolution process of in- situ stress is simulated using the Universal Distinct Element Code( UDEC),by consideration of the valley asymmetric development. The numerical results are as follows: the phenomenon of high in- situ stress fold occurs in the river valley bottom with an obvious stress concentration at the depth of 130 m,and the magnitude of the maximum principal stress is 28 to 34 MPa. The in- situ stress field along the bank slope is characterized as the belt distribution,which can be divided into the stress relaxation zone and original stress zone. The horizontal depth of stress relaxation zone is approximately 200 m at the left bank and 120 m at the right bank. In addition,further analysis of the mechanisms of asymmetric stress evolution is carried out; it is found that the asymmetrical valley evolution is the main cause for the different in- situ stress of two banks,in which,a reciprocating process existed,including the stages of valley incision,landslides accumulation and valley bottom migration.