Xu H.,University of Sichuan |
Zhou Z.,HrdroChina Chengdu Engineering Corporation |
Xu J.,University of Sichuan |
Ren H.,HrdroChina Chengdu Engineering Corporation |
And 4 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013
The weakening effect of high water head on dam foundation weak rock masses after impoundment for Jinping I hydropower station is a highly concerned subject for its engineering construction. A series of testing methods are suggested to reveal the weakening effect. Based on a geological process-mechanical mechanism simulation-mechanical parameter control theory, rock mass replica specimens can be prepared with complete process of triaxial compression test and used for hydro-mechanical coupling test. A series of triaxial compression tests with the confining pressures of 5, 10, 15, 20, 25, 30 MPa are performed on the replica specimens under current natural state and hydrostatic pressures of 1-4 MPa. The result has shown that, the weakening effect is quite significant in the shallow low stress rock mass, the weakening rate of strength parameter f is within 13%, while the weakening effect of c increases dramatically up to 100% with the increasing hydrostatic pressure. The weakening rates of deformation modules increase with the increasing hydrostatic pressure when confining pressure is below 20 MPa, and decrease when confining pressure increases. However, when confining pressure exceeds to 20 MPa, the weakening effect is negligible. A prediction model of rock mass mechanical parameters is established according to the results. These achievements have already been applied to the engineering construction of Jinping I hydropower station, and the research techniques have opened up a new laboratorial way for research on rock mass mechanical properties.