Vol14 No.7: 1428-1444
【Title】Interaction between anti-shear galleries and surrounding rock in the right-bank slope of Dagangshan hydropower station
【Author】LI Lian-chong1*; XING Ya-zi2; LIU Xing-zong2; MA Ke2; XU Nu-wen3; ZHANG Fei1
【Addresses】1 School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China; 2 School of Civil Engineering, Dalian University of Technology, Dalian 116023, China; 3 College of Water Resources and Hydropower, Sichuan University, Chengdu 610065, China
【Citation】Li LC, Xing YZ, Liu XZ, et al. (2017) Interaction between anti-shear galleries and surrounding rock in the right-bank slope of Dagangshan hydropower station. Journal of Mountain Science 14(7). DOI: 10.1007/s11629-016-4318-3
【Abstract】The right-bank slope of the Dagangshan hydropower station located in Southwest China is a highly unloaded rock slope. Moreover, large-scale natural faults were detected in the slope body; some excavation-induced unloading fractures were discovered at elevations between 1075m and 1146m. Because of poor tectonic stability, the excavation work was suspended in September 2009, and six large-scale anti-shear galleries were employed to replace the weak zone in the slope body to reinforce the right-bank slope. In this study, based on microseismic-monitoring technology and a numerical-simulation method, the stabilities of the slope with and without the reinforcement are analysed. An in-situ microseismic-monitoring system is used to obtain quantitative information about the damage location, extent, energy, and magnitude of the rocks. Thus, any potential sliding block in the right-bank slope can be identified. By incorporating the numerical results along with the microseismic-monitoring data, the stress concentration is found to largely occur around the anti-shear galleries, and the seismic deformation near the anti-shear galleries is apparent, particularly at elevations of 1210, 1180, 1150, and 1120m. To understand the interaction mechanism between the anti-shear gallery and the surrounding rock, a 2D simulation of the potential damage process occurring in an anti-shear gallery is performed. The numerical simulation helps in obtaining additional information about the stress distribution and failure-induced stress re-distribution in the vicinity of the anti-shear galleries that cannot be directly observed in the field. Finally, the potential sliding surface of the right-bank slope is numerically obtained, which generally agrees with thespatial distribution of the in-situ monitored microseismic events. The safety factor of the slope reinforced with the anti-shear gallery increases by approximately 36.2%. Both the numerical results and microseismic data show that the anti-shear galleries have a good reinforcement effect.
【Keywords】Slope stability; Microseismic monitoring; Numerical simulation; Safety factor; Anti-shear gallery