Integrated Geophysical Survey in Defining Subsidence Features of Glauber's Salt Mine, Gansu Province in China

Integrated geophysical surveys using ground penetrating radar (GPR), seismic and electrical resistivity tomography, are carried out to characterize the subsidence, combining with engineering examples in the Glauber's salt mining area in the northwestern region of Gansu Province, China. Because some of the dissolved ore bodies in the Glauber's salt mining area are accompanied by the top and floor, the geophysical response of the floor strata has different physical properties. It is theoretically feasible to use resistivity imaging, GPR and seismic methods to detect. However, it is very necessary to choose an effective geophysical method through experimentation. the limitations of electrical resistivity tomography method and GPR are discussed: in actual work, if the electrical difference between the target body and the surrounding rock is not large enough, the conventional electrical resistivity tomography method cannot be used for fine detection; due to factors such as human noise from the mine's annex, the GPR electromagnetic wave reflection method cannot carry out effective work. Seismic refraction tomography processing is discussed and it was found that the interpretation results of refraction wave tomography can better distinguish the strata in the sub-survey area, which has an excellent effect on the delineation of the range of dissolution and collapse in Glauber's salt mine. Theory and engineering examples prove that seismic refraction wave tomography technology has good applicability in the detection of underground dissolution areas in Glauber's salt mines.