INFLUENCE RESEARCH OF SLOPE BLASTING EXCAVATION ON ADJACENT EXISTED TUNNEL
LI Ning1,2,ZHANG Chengke1,ZHOU Zhong3
(1. Institute of Geotechnical Engineering,Xi?an University of Technology,Xi?an,Shaanxi 710048,China;2. State Key Laboratory of Frozen Soil Engineering,Cold and Arid Region Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou,Gansu 730000,China;3. HydroChina Chengdu Engineering Corporation,Chengdu,Sichuan 610072,China)
Abstract:The effect of slope blasting vibration on an adjacent existed tunnel and its control are key problems of tunnel project. Since the new slope is close to existing tunnel,the seismic wave induced by blasting endangers the safety and stability of the surrounding rock and the lining of existing tunnel. For a different distance between slope and tunnel,a different rock mass damping ratio,how much safety explosive quantity for single blasting in project is in urgent need of solution. On the basis of the simulation with the dynamic finite element method(FEM),the effects of slope blasting vibration on the surrounding rock and lining structure of adjacent existed tunnel in different distances between slope and tunnel,damping ratio,safety explosive quantity for single blasting are studied,combining with influence of slope blasting on tunnel analysis issue on Jinping I hydropower station left bank project construction. According to the tunnel wall permitted vibration velocity and lining dynamic tensile stress caused by slope blasting vibration wave,obtain maximum explosive quantity of slope blasting constructions considering different damping ratios under different distances between slope and tunnel and different rock types:grade III rock mass,when distance between tunnel and slope equal to 20 and 50 m,the explosive quantity should be controlled in 100 and 300 kg respectively;grade IV rock mass,when distance between tunnel and slope equal to 20 and 50 m,the explosive quantity should be controlled in 150 and 450 kg respectively,and the research results provide the reference and basis to construction and design of the actual project.
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