Reseach On The Unloading Characteristics Of Rock Mass And Its Impact On The Project On Left Dam Abutment Slope Area Of Batang Hydroelectric Power Station

Batang hydropower station is located in the Western deep valley area,where rock mass unloading is strongly.The study of the characteristics of the unloading rock mass and Unloading zoning have important theoretical and engineering significance for rock mass excavation in construction stage and for studing distribution of groundwater during reservoir operation.The paper,whose research object is Batang hydropower station dam area rock slope,which based on domestic and foreign research status and a lot of field survey and statistical analysis,contains the dam site rock unloading failure characteristics,divide rock of slop unloading zone,studied the influencing factors and formation mechanism of unloading of rock mass.At last,the characteristics of seepage field and stability under seepage flow of unloading rock slope were discussed.(1)Research of basic features and filling material and deformation and failure characteristics of unloading rock mass shows that the rock mass of dam area unload strongly and Tension cracks filled much filling material.(2)The study which quantitative partitioning of unloading zone of rock mass using fracture opening degree and open fracture line density and wave velocity of flat tunnel under the basis of qualitative division found that the unloading depth of the study area is deep and the unloading depth of different adit was great through qualitative and quantitative analysis.(3)Combined with the qualitative analysis of the cause mechanism of the rock mass unloading,simulating the deformation and failure characteristics and scope in the valley cutting stage by finite element numerical simulation.Finally,simulating the effect of earthquake on the slope unloading by the discrete element method,and getting the conclusion that earthquake exacerbated the development of unloading.(4)Studying on the seepage characteristics of slope under the condition of natural dam and storing water using the MODFLOW software,and calculating the seepage quantity of slope by using the analytical solution and numerical simulation.The results of numerical calculation results are consistent with the qualitative results.The research results show that the adjacent valley seepage and dam-detouring leakage quantity are in a reasonable range.(5)Establishing the corresponding numerical simulation model,and calculating the seepage field characteristics of unloading rock mass and the slope stability under the effect of solid-fluid interaction.The calculation shows that the overall stability of slope is better.