Rock Relaxation Effect Study On The Left Bank 690m To 630m Foundation Rockof A Hydropower Station In Southwestern

Complex and high crustal stress,high and steep rock slope were the characteristics of spandrel groove high slope of a hydropower station in southwestern.The slope is excavated in the 630 m elevation.Accompanied by excavation,excavationslopebecomesslower.Thestructuresinclude Ls3319,Ls3319-1,Ls3319-2havebeenexposed.Thestructureswere interaction cutting and limiting the excavation face and the fault F17.They established the wedge with excavation face of the left bank.Superficial department is basically in the wedge.Grew up structural plane cutting and combination of block rock relaxation has the obvious magnification effect of excavation,so the dam foundation rock mass quality declined.The author combined with domestic instances of this kind of high arch dam excavationunloading relaxationcomparative analysis,researchedon the structures'proper characters and the space distribution characteristics.Investigated developmental characteristics of the deformation and failure characteristics of the irrigation and drainage hole.The author obtained the depth of the rock mass relaxation characteristics and timelinessby monitoring the inner rock through supersonic wave.Finally the author forecasted the relaxation effect of rock mass by numerical simulation.It has important guiding significance to the hydropower station's construction,and the design of anchorage.The specific results is:(1)Researched on the structures'proper characters and the space distribution characteristics of the foundation rock for the excavation690m~630m.Established three-dimensional solid model,analysised the complex combination block boundary conditions.(2)Detailed investigated the relaxation characteristics of 690m~630m rock mass,including the relaxation characteristics of the superficial foundation rock and failure characteristics of the irrigation and drainage hole.(3)Divided the relaxation zone of the foundation rock with thickness by monitoring the sonic wave holes.It is concluded that structures'combination and limit have amplification effect on the relaxation depth of the foundation rock.(4)Researched on the relaxation timeliness by repeatedly monitoring borehole's acoustic wave.It indicated that the strctures'limit has amplification effect on the superficial foundation rock and the rock mass near the structures.(5)The author used FLAC~3dd to simulate the process of step-by-step excavation of the foundation rock and forecast the relaxation effect of the 630m~545m rock mass.The results showed that the shallower structures influence the relaxation effect of the foundation rock mass near the structures stronger.