Application Of High-density Resistivity Method And Ground Penetrating Radar In Typical Engineering Exploration

With the acceleration of urban process,infrastructure projects such as subway,underground pipe and civil engineering are developing rapidly.People are developing more and more underground space.Therefore,it is necessary to detect and locate the underground diseases and historical buried buildings,so as to guide the safe construction and hazard prevention.High-density resistivity method and ground penetrating radar,as the important engineering exploration technology of near surface,are the important means to obtain geological data in the early stage of engineering construction.They have been widely used in the construction and maintenance of traffic infrastructure such as subway and tunnel geological exploration,detection of urban road hidden dangers,detection of road settlement.They can be applied to engineering exploration because of the physical differences between different underground media.As a branch of resistivity method,the high-density resistivity method is based on the difference of conductivity between different underground media.Ground penetrating radar is based on the dielectric difference of different underground media.The physical differences between the underground abnormal structures such as loose soil,cavity,water bearing area,separation and fracture and the surrounding media are the premise of their detection and location.In order to improve the accuracy of anomaly interpretation in survey-line profile.In this paper,the development course,principle and method of the two geophysical methods are introduced.Then through the analysis of typical engineering cases,the characteristics of electromagnetic reflection wave and resistivity of different geological anomalies are summarized.It has guiding significance for comprehensive geophysical interpretation in practical engineering detection.The cases are as follows.1.Pipeline leakage detection.The leakage point of underground water supply pipeline in urban area is investigated by high-density resistivity method.2.Tunnel engineering detection.The weathering degree of rock mass and the distribution of fracture along the proposed tunnel line are investigated by high-density resistivity method.3.Historical buried reservoir detection.The high-density resistivity method is used to investigate the location and distribution of the reservoir under the proposed construction area.4.Subway engineering detection.Ground penetrating radar is used to investigate the cavities and their distribution along the proposed subway line.5.Detection of urban road diseases.Ground penetrating radar is used to investigate whether there are defects such as loose soil layer,cavity and separation in the depth range of 5m below the urban road and the distribution range.