Numerical study on urban hidden geological hazard detection based on the semi-airborne transient electromagnetic method

As a relatively common geological disaster, ground collapse often occurs in urban areas. In view of the complex urban environment, and to effectively identify the areas with potential ground collapse, a new detection method was researched for the demand of fine exploration for urban underground hydraulic connection channels. According to the actual situation, the source was flexibly arranged in areas with good grounding, such as flower beds on the ground. An unmanned aerial vehicle (UAV) was adopted to carry the receiver for data collection in the air. This method would less affected by the flight height, and is thus more suitable for urban environments with tall buildings. Then, geological modeling was built based on the real geological conditions of a city, four underground hydraulic connection channels were set, and the method in the paper was used for detection. The apparent resistivity results effectively present the characteristics of the hydraulic connection channel. The method also provides an effective means for the detection of urban underground hydraulic connection, as well as a basis for efficient investigation with potential ground collapse and corresponding prevention and treatment in advance.