Abstract: With the increasing utilization of the urban underground space, the karst sinkhole hazards caused by the human activities including engineering activities are becoming more and more frequent. Both soil and rock cavities in the karst terrain are developed underground and their evolution mechanisms are complicated, so it is difficult to detect their evolution mechanisms and degree of development by conventional methods. To reduce the threat of karstic collapse hazards to human life and property loss, a well-developed karst terrain in Shenzhen City was used as an example. A two-dimensional section of karst exploration results was obtained by the cross-hole seismic tomography method, which is visually demonstrated the spatial location and morphology of soil and rock cavities. The tomography results also improved the visualization of interpreted results. The test results identified the distribution range and development pattern of soil and rock cavities and rock pinnacles in the area, and these results were validated with the test boring drilling results. Based on the results of the field investigation combined with the regional geological data, the causes of strong karst development in the area are analyzed and emergency management measures are proposed in the paper. The results also provide background data for the minimization and control of the karst collapse in the city.

Key words: Tomography, Karst Terrain, Sinkhole Collapse, Urban Geological Hazards