Study Of Coil Parameters Optimization Based On The Transient Electromagnetic Method For The Road Collapse Detection

Due to the large increase of urban underground pipeline and the acceleration of urban metro construction with the development of the cities in our country,more and more roads collapse accidents occurred in our lives,which become invisible risks gradually for a city and also threat the lives of people at any time.Therefore,surface collapse event has received comprehensive attention of the society since it has become the potential pitfall in the city.Accordingly,experts have carried out many relevant works in the prevention and detection of urban road collapse,hoping to make advanced tests and do some protective measurements before the collapses emerge in dangerous areas.Nowadays,there is a variety of methods for collapse detection,including shallow seismic method,ground penetrating radar method,transient electromagnetic method(TEM)and so on.Shallow seismic and geologic radar methods have inconvenience to some extend because workers must close the road when it is detected and measured.Relatively,TEM has advantage on detecting depths and high resistance to interference so that it is widely researched by scholars,however,there are also some shortcomings to be improved in the collapse detection for TEM,for example,the collapse detection data processing will be lagged because it is impossible to analyze the measurement data in time in the detection situ;some inappropriateparameters such as the length and turns of coil,the magnitude of electric currentwill be used,which will have great influences on detecting and the portability of the subsidence detectors;the parameter optimization algorithm is quite various,it's necessary to master every algorithm especially their shortcomings so that we can reasonably select which algorithms can be used to optimization algorithm.Additionally,it is important to know which methods can be used to criterion for optimization algorithm.To address the aforementioned issues,this paper firstly analyze the parameters of transientTo address the aforementioned issues,this paper firstly analyze the parameters of transient electromagnetic coils so that we decide to optimize the parameters including the transmitter current,the side length and the number for coil and so on.Secondly,we compare with some optimization algorithm,choose and improve the genetic algorithm and make a performance test for the improved genetic algorithm.Then,we apply Ansoft Maxwell electromagnetic simulation software to do modeling and Matlab software to do numerical simulation,use the improved genetic algorithm to optimize coil parameters.Finally,we process the collected data and realize the visualization implementation and graphical representation of measurement data.The influence factors of selecting coil parameters for transient electromagnetic method(TEM)is more complicated,such as coil self-induction,underground material resistivity and so on.Given that,this paper select the magnitude of coil current,the number of coil turns,the size of wire-frame and the array distance of coils as research parameters,and regard the focus capability of transmitter coils as a criterion,it has shown that the parameters optimization of coil gets a satisfactory result by experiments because it has an positive effect to improve the detection quality and reduce the cost of coils manufacture and trials.