Study On Leakage Model Of Earth-rock Dam Based On Natural Tracer Method

Earth-rock dam is one of the important dam types in water conservancy projects.Leakage damage is one of the main factors leading to the failure of earth-rock dam,and the identification of leakage channel is the key and difficult problem.The natural tracer method has been used in the identification process of earth-rock dam leakage channels due to its advantages of low cost,no pollution,and high efficiency.However,its low degree of quantification,low degree of independence,and low degree of modeling Restricted its further promotion and use.In this paper,the temperature and conductance in the natural tracer method are selected as tracers.The coupling model of seepage field and temperature field,seepage field and electric field model are established.The main research results are as follows:(1)Summarizes the domestic and international research progress in detecting leakage channels of earth-rock dams,and analyzes the applicable conditions,advantages and disadvantages of methods such as direct analysis,geophysical detection and comprehensive tracing(natural tracing and artificial tracing)methods In the natural tracer method,temperature and conductance are used as tracers,and a seepage field-temperature field coupling model and a seepage field-electric field model are established.(2)Based on the temperature tracer method,the influence of different forms and locations of seepage channels on the seepage field and temperature field of earth-rock dams was studied.The results show that the leakage channel will cause the change of the seepage field of the earth-rock dam.The change of the seepage field will cause the change of the temperature field,and the change of the temperature field will in turn affect the seepage field.This is because the heat transfer in the earth-rock dam is affected by heat convection and heat conduction.Heat convection refers to the heat transfer phenomenon of the dam body caused by seepage.The faster the seepage,the faster the heat transfer;Heat conduction refers to the solid particles heat transfer phenomenon affected by thermal motion.The change of seepage field of earth-rock dam will change the speed of heat transfer,thereby change the temperature field;the change of temperature will change the density of fluid,dynamic viscosity coefficient,etc.,thereby change the permeability of earth-rock dam,and finally cause the change of seepage field.Therefore,it is recommended that in actual engineering,by monitoring the temperature change of the dam body,the space-time distribution of the seepage field is fed back to determine the location of the leakage channel(3)Based on the conductivity tracer method,the seepage field-electric field model of the earth-rock dam is analyzed,and the influence of the leakage channel on the electric field is studied.The study found that the leakage channel will first change the seepage field of the earth-rock dam,and then affect the electric field distribution.This is because the change of the seepage field changes the conductivity of the earth-rock dam,thus changing the electric field Therefore,if the temperature sensor in the dam fails,the conductivity monitoring can be used as an effective supplementary measure to determine the leakage path of the earth-rock dam.