Seepage On Field Numerical Simulation Of Chu Shan Dian Earth-rock Fill Dam Under The Conditions Of Water Level Fluctuation Of Reservoir And Rainfall

The seepage problem is an important part of safety and stability analysis of earth-rock dams,permeation damage caused by seepage can easily cause earth-rock dam failure,the consequences are often very serious.In the actual operation of the dam,the water level of the reservoir often changes,including wa ter storage,water discharge,etc,and often encounters rainfall,especially heavy rain.Therefore,this situation should be taken into account in the seepage analysis of earth-rock dam,that is non-steady seepage analysis.At the same time,because the unsaturated soil occupies a large part of the seepage analysis,it is not enough to consider the seepage as the seepage of saturated soil.The seepage problem mostly includes both saturated and unsaturated seepage,and the two as a whole.The study of seepage problems is closer to reality.In addition,for the earth dam and the concrete dam connection section,the binding sites are relatively weak,the properties of the two materials are quite different,and the seepage field is also complicated to change,and its safety is very important.Therefore,it is necessary to study the characteristics of the seepage field of the earth dam section and the connecting section under the conditions of reservoir water level fluctuation and rainfall.It is also conducive to the adjustment and optimization of the construction,so as to better protect the safety and stability of the dam body.This paper takes the earth-rock dam of the C hushandian Reservoir as the engineering background,and adopts numerical simulation method to study the characteristics of the seepage field of the earth dam section and the connecting section under the conditions of reservoir water level fluctuation and rainfall,mainly carried out the following aspects of the work:(1)The basic theory of seepage flow was studied and analyzed.The saturated-unsaturated seepage differential equations were summarized and deduced,and the conditions for definite solution were given.Several methods to determine the parameters of unsaturated seepage were described.(2)Using the SEEP/W finite element analysis software to establish a 2D seepage analysis model for earth dam section,and numerical simulations of the stable seepage field under the different working conditions,elevation of reservoir water level and transient seepage field under rainfall conditions.Summarizes the changes of the seepage line,pore water pressure,volumetric water content and hydraulic gradient of the dam.(3)Using the Midas GTS NX finite element analysis software to establish a 3D seepage analysis model of the connecting section,mainly analyzed the stable seepage field and the drop of the reservoir water level and transient seepage field under the rainfall conditions of the connecting section dam under different working conditions.A iming at the phenomenon of seepage around the thorn wall and its variation characteristics of seepage field,the paper analyzes and summarizes the changes.