Thermal Coupling Model Of Concentrated Leakage Flow In Levees And Dams And Laboratory Test Research

The vast majority of our country water conservancy projects are dyke projects,and these dams play an extremely important role in flood control,storage and national economy.Hidden seepage hazards are the main threat to the safety of dams.The seepage heat monitoring technology indirectly finds abnormal leakage points in the dam by monitoring the temperature distribution of the dam,and obtains the distribution of the seepage field in the dam body,so as to achieve the purpose of monitoring the seepage of the dam.Based on the proposed new thermal conductivity model,this paper uses a combination of physical model test and numerical simulation to study the relationship between the temperature field of the dam under different infiltration heads,different seepage channels,and different infiltration water temperatures.The changing law of seepage field.And.use the experimental data to verify the accuracy and feasibility of the dam saturation-unsaturated flow-thermal coupling model based on the new thermal conductivity model.The main research results are as follows:(1)According to the measured data of the indoor test,when the temperature of the infiltration water is higher,the concentrated leakage of the dam will occur faster,and the impact on the temperature field and seepage field of the dam will be greater.The slower the rate of concentrated leakage and the destruction speed of the dam;when the infiltration head is higher,the time of concentrated leakage of the dam is earlier,and the single-width seepage flow of the dam body is greater;when there is a concentrated leakage channel in the dam body At this time,the seepage flow rate and single-width seepage rate of the dam body are far more than the working condition without concentrated leakage channel.(2)Combining the indoor test data and numerical simulation data based on COMSOL Multiphysics using Lu(2007)model,Lu(2014)model and Ren(2019)model,from the three evaluation indicators(RMSE,Re and R~2)It can be seen that the temperature data of the embankment simulated by the Ren(2019)model based on COMSOL Multiphysics is more consistent with the measured temperature data.(3)From the seepage field simulation results,the streamlines of the dam body are evenly distributed throughout the dam body without concentrated leakage.When there is concentrated leakage,the streamlines of the dam body are abnormal,and most of the streamlines are concentrated.Near the concentrated leakage channel,the streamlines in other dam areas are sparsely distributed.(4)From the comparison between the measured piezometer head data and the simulation results,the simulated value based on the Ren(2019)model is more consistent with the actual measured value,and the prediction is more accurate.The Ren(2019)model based on COMSOL Multiphysics has a good simulation effect and can accurately describe the dynamic change process of the seepage field of a dyke.(5)The dyke flow-thermal coupling model of the built Ren(2019)model is used for the core earth-rock dam.The results show that the Ren(2019)model is suitable for the study of the flow-thermal coupling model of the earth-rock dam and can accurately reflect the temperature of the earth-rock dam The coupling process of field and seepage field.Concentrated leakage affects the temperature field distribution through the seepage field.Concentrated seepage channels at different heights have different effects on the temperature field of the dam.Monitoring the internal temperature field of the dam through embedded sensors can reflect the seepage field of the earth-rock dam in real time,and can be found in time Problems and eliminate hidden dangers.