RESEARCH ON MODEL EXPERIMENT OF TRANSIENT ELECTROMAGNETIC METHOD TO DETECT DEEP UNDERGROUND CAVITIES IN COMPLEX TERRAIN

To study the application of the principle and technology of TEM prospecting, the authors designed experiments to detect deep-buried caverns under different landforms (mount, valley, slope with different angles). Under the precondition of similarity, by geometrical scaling and actual physical property simulation, response field results same as or proportional to that of prototype are obtained. The authors studied the design of configurations of model experiments, the preparation of experiment materials, the model building, the data acquiring and processing, and got the response characteristics of spherical and cylindrical targets by different devices (superposition, center, and dipole) under complex terrain conditions. The study can provide the principle and data foundation for identifying spherical or cylindrical objects with low resistivity under uneven land surfaces and evaluating the validity of detecting underground caverns by TEM.