Research On Electromagnetic Simulation And Early Warning Method Of Hidden Troubles In Dam

The dam project is a common water conservancy facility in China,which undertakes the adjustment function of hydraulic resources and an important protective role,and is closely connected with the national economy and people’s livelihood.In China,the main types are earth and rock dams,which are numerous and widely distributed.The structure of the earth-rock dam is relatively simple,and the material for landfill construction is relatively simple.It is more susceptible to factors such as temperature,climate,and surrounding geological activities,resulting in structural changes,resulting in internal dams that can threaten the stability and safety of the dam body.Hidden hazards,so the monitoring and detection of hidden hazards of dykes and dams is particularly important.As the country continues to pay attention to the safety of water conservancy projects,the demand for hidden danger detection of dam facilities is increasing.Based on the existing geophysical detection methods,the DC resistivity method is used to monitor the different time characteristics of hidden dangers and the precision of transient electromagnetic water array sources.Detection,multi-layer detection of hidden dangers of dikes to ensure that hidden dangers of dikes are effectively controlled and properly handled before causing major accidents.The DC resistivity method is a fast and simple detection method,but it is limited by theoretical principles,and the detection accuracy is difficult to be significantly improved on the original basis,and it cannot meet the detection needs of small hidden dangers of dams.Compared with the traditional method of directly detecting the abnormal reflection of the geological body,considering the occurrence of hidden dangers of the dam,it will change in shape,size and position with the passage of time and changes in external conditions,showing obvious changes in electrical structure and monitoring its The accuracy of the variation is lower,so this paper uses real-time apparent resistivity characteristic imaging methods to realize realtime monitoring of earth-rock dams.The current theories of dam monitoring techniques with different time characteristics are mainly based on one-dimensional or two-dimensional medium models,and it is impossible to accurately describe the electrical change characteristics of threedimensional dam structures at different times.For this reason,this paper uses high-density DC resistivity detection theory and uses three-dimensional The forward modeling method of structural finite element numerical simulation is used to accurately simulate the characteristics of the DC electric field at different times in a typical dam hidden-danger model,and to analyze the response change law.The numerical simulation results show that the monitoring results have a good reflection on the change trend of dam hidden dangers,and changes in the size,location and shape of dam hidden dangers can cause regular changes in the monitoring abnormal amplitude and position.Real-time continuous monitoring of hidden dangers of dams is a low-cost and highly effective preventive method.It aims to quickly detect the location of hidden dangers,but it is not enough to meet the requirements of fine detection of hidden dangers.On this basis,this paper introduces the array source transient electromagnetic method to carry out fine detection of the non-destructive location of hidden dangers inside the dam.The array source is a highperformance excitation source with strong resolving power,but it is difficult to excite in the actual work on the ground.Therefore,this paper improves the form of the device and places the array source in the river water upstream of the dam through the water-carrying tool.The time-domain three-dimensional finite element method,on the basis of changing the loading method of the source item,realizes the forward electromagnetic simulation of the three-dimensional time-domain finite element of the electromagnetic array source in water.This method is used to study the response characteristics of the array source in water and discuss the array source Different parameters affect the performance of the source.At the same time,three-dimensional modeling of several typical types of hidden dangers of dams was carried out.Under the excitation conditions of the array source in the water,the electromagnetic field attenuation of various hidden danger types was analyzed by forward modeling the types of tubular leakage,layered leakage and cave hazards.Characteristic law,and electric field distribution after turning off.The research results show that the underwater array source can improve the resolution of the secondary induction field of the dam’s hidden troubles,and the resulting decay curve of the hidden troubles has a good anomaly reflection,which can achieve the purpose of fine detection of the hidden dangers inside the dams.In this paper,based on the simulation results of continuous monitoring and fine detection,a complete dam warning method is formed.The research results can provide guidance and help for the design of actual equipment and the application of field work in the future.