Seepage Simulation Of Rock Mass Under The Control Of Continuous Gently Dipping Soft Interlayer And Steeply Dipping Joint

Water conservancy project of bedrock affected by multiphase tectonic movement,there is a complicated fissure system in the construction of the dam foundation rock mass itself contains the permeability of rock mass,the related physical and mechanical properties will be due to the structure of this kind of defect have great change,part of the rock mass on the part weight of uplift pressure can be produced in weak intercalated offset,so that the anti-sliding performance of the dam foundation rock mass itself is abate,at the same time exist in the joints and cracks in the rock mass of dam foundation uplift pressure might cause slippery effect increase the power,in both the stability of the dam foundation rock mass under the function of its own decline substantially.Therefore,it is necessary to further analyze the seepage of dam bedrock.This paper made a detailed investigation on the engineering geological conditions of the sluice of datengxia water conservancy project,and carried out seepage simulation for the no.29 dam section by means of numerical simulation.The results are as follows:(1)through field investigation,the engineering geological conditions of the study area were clarified.Based on the statistics of joints and cracks in the field investigation,the structural characteristics of the dam foundation rock mass are analyzed.The outcropping rock of the dam foundation is mainly limestone of the yujiang terrace and the nagaoling formation.The rock mass is well stratified and usually in a closed state,and the spacing of stratification is mostly 10~40cm.The occurrence of the weak interlayer is basically the same as that of the bedding layer,and the spacing is usually 2~5m.The physical properties of the weak interlayer are relatively stable.(2)uplift pressure is a very important parameter in seepage analysis and hydraulic engineering analysis.The normal method is used to calculate the uplift pressure at the bottom of the dam and the structural surface,and the distribution of uplift pressure in the seepage field in the study area is analyzed with or without a curtain.(3)based on discrete element numerical simulation of large cane gorge hydropower station dam foundation seepage simulation analysis,the model of seepage flow is stable,through the curtain seepage flow would be significantly lower than no conditions of seepage flow,this suggests that the impervious curtain has a certain degree of waterproof effect,and two kinds of working conditions of seepage flow in fault obviously reduced,combined with the results of 2 presumably due to the fault existing in the fault materials such as mud,make fault within the crack width,crack width is less than the rock mass seepage through fracture,due to the crack width and results in a seepage flow in the fault sharply decreases,and thus lead to uplift pressure decreases.After analyzing the ground motion load applied on the model,the water pressure of the fracture water in the model increases obviously,indicating that the water pressure will increase to a certain extent under the dynamic action.(4)the calculation results of the standard method and the numerical simulation results are compared and verified.The results show that the data results of the numerical analysis and the distribution characteristics of uplift pressure are similar to the calculation results of the standard method,with a difference of less than 10%.Therefore,this simulation can be considered reasonable.