Study On Optimization Design Of Right Abutment High Slope Of The Qianping Reservoir

Right abutment slope of Qianping reservoir is high and steep,which is up to 100 m after excavation.The bedrock mainly is andesitic porphyrite and it is exposed,mosaic-fragmentation structure.The stability of slope will directly affect the construction safety of the project.The structural characteristics of the right abutment rock is analyzed by three-dimensional laser scanning technique,two group of fissures are unfavorable to the stability of slope and may cause shallow slide,of which the tendency are same to the slope.The excavation slope ratio is set to 1:0.5 according to original design scheme,and there is no berms on the slope surface.According to the optimization design scheme,excavation slope ratio is increased to 1:0.3,4-level berms with 3m wide are added,a flexible protecting net on the slope surface is added to avoid the damage by the rockfall after uploading of rock.The stability of slope is analyzed by the limit equilibrium method,FLAC3 Dnumerical simulation and reliability analysis method respectively.According to the optimization design scheme,when the slope is fully excavated,the safety factor is 1.49,there is no tensile stress in the slope,the maximum deformation of the slope is 2.13 cm,the reliability index is 4.07;according to the original design scheme,when the slope is fully excavated,the safety factor is 1.50,there is tensile stress in the slope,the maximum deformation of the slope is 2.39 cm,the reliability index is 4.40.The overall stability of the right abutment slope after excavation meets the requirement of code according to the optimization design.Construction according to the optimization design scheme can lessen the excavation volume of rock about 100,000 m3,and then lessen the same amount of dam filling material.What's more,the construction period can be shortened greatly.Above all,the optimization design scheme can generate notable economic and social benefits.