Application Of Geophysical Exploration Methods In Geological Hazard Investigation

China has complex geological conditions and many types of geological disasters.Due to the great destructiveness of geological disasters,it poses a great threat to all types of engineering construction and people's lives and property.A detailed geological disaster investigation is conducted on the areas of construction and human activities.The investigation and delineation of geological hazards that are of high risk and cause great losses provide guidance for disaster protection and risk control.There are many geophysical exploration methods currently used for geological disaster investigations,and the basic theories based on them are also different.The commonly used methods include: high-density electrical methods,geological radar methods,seismic reflection methods,and radioactive methods.Each method has its own advantages and limitations.If a single geophysical exploration method is used to conduct a geological disaster investigation based on only one physical property parameter,the accuracy of the obtained results is not high enough.At the same time,the single geophysical method can not effectively suppress the multi-solution problem,and there is a large interference to the data interpretation.The two geophysical methods are combined to exploit the respective advantages of the geophysical methods.By comparing the geophysical data with each other and analyzing the subsurface media from multiple parameters,the problem of multiplicity is reduced,and the accuracy of exploration and the reliability of results are greatly increased.In this paper,the high-density electrical method and shallow seismic reflection wave method are used for joint geological disaster investigation.The characteristics of high-density electrical method and shallow seismic reflection method,basic theory,field work method and indoor data processing flow are analyzed.The Frechet derivative is introduced and the sensitivity analysis of each device is presented.The applicability of each device of high-density electrical method is summarized,and the basis for the selection of devices in practical work is provided.Least squares method,least-squares method under smooth constraint and robust inversion method are analyzed.The basic theory and the comparison of the results of each inversion method are presented,and a method for improving the resolution of high-density electrical inversion results is proposed.In the shallow seismic reflection wave method discussion,the shallow seismic reflection wave method is summarized and the feasibility of the geological disaster investigation is summarized.The factors affecting the seismic wave field and the propagation law of the seismic wave are analyzed;different methods of geophysical exploration are available.Their respective advantages,but there are also some deficiencies.This is also the purpose and significance of joint exploration using geophysical exploration methods.Combining the advantages,disadvantages,and adaptability of the two geophysical methods,based on engineering examples,high-density electrical methods and shallow seismic reflections are used to investigate and analyze geological hazards.The general location of disasters is divided and delineated,and the deep geological features are prospected through the shallow seismic reflection wave method.The two geophysical exploration results are comprehensively compared and analyzed to provide guidance for the protection of geological disasters.