Study On Infrared Imaging Technology For Concentrated Leakage Dectection In Earth-rock Dam

Leakage risk is becoming increasingly severe for earth-rock dams,resulting in the risk of presence of piping,failure and other accidents rising.How to detect hidden leakage,and adopt timely and effective reinforcement relates to safety of reservoirs.After comparison of temperature field detection method with other various detection methods,we focused on infrared thermal technology in non-destructive test,trying to use this technology detecting leakage risk in earth-rock dams.We conducted indoor tests and numerical analysis.The main content and results of the study is divided into two parts:(1)Research on rules of Infrared thermal imaging detection for concentrated leakage in homogeneous dams and core wall dams.First,we conducted indoor tests.We made two reduced scaled models,homogeneous dam model and core wall dam model with concentrated leakage,Infrared radiation was used as heat source to simulated solar illumination for dams in engineering,infrared thermal imaging instrument M7500 was used to measured temperature changes in the tests.Results show that temperature of concentrated leakage region is lower than normal region on the model,absolute temperature difference and relative temperature difference of leakage region and normal region expanded with time.Using finite element software Geostudio 2007 for temperature field and seepage field coupling analysis.Results show that temperature of concentrated leakage region is lower than normal region,absolute temperature difference and relative temperature difference of leakage region and normal dam region expanded with time,which is consistent with indoor tests.(2)Effect of head on infrared thermal imaging detection.In indoor tests,three head were used in the tests,namely 10 cm,15 cm,20cm head difference.Results show that when head increased,absolute temperature difference and relative temperature difference increase as well.In numerical analysis,five head were used,namely 5cm,10 cm,15 cm,20cm,25 cm head difference.Results show that absolute temperature difference and relative temperature difference increase with head,which is consistent with indoor tests.Numerical results also show that water velocity of leakage region is larger than normal region.When head increases,the gap of water velocity expands as well,temperature abnormity becomes more apparent.