Researches on detection of 3-D underground cave based on TEM technique

Because of unreasonable coal mining in China, there are many unknown underground caves, and the inhabited environment of humans is threatened by many geologic hazards, such as cracking of the buildings, ground subsidence, etc. To make the coal companies aware of the harmfulness of these hazards, it is urgent to determine the reasons for the hazards. In this paper, transient electromagnetic method (TEM) is used to detect the ground resistance caves, instead of the time-consuming and expensive direct drilling survey. Numerical results of the 3-D synthetic model and real field survey data are given. The results showed that the TEM method can be used to detect a complicated air-filled underground 3-D cave and coincide with the results of direct drilling survey.