Characteristics, Controlling Factors, and Formation of Shallow Buried Karst in Eastern China: A Case Study in the Wuxi Metro Areas, Jiangsu Province

摘要

Karst-related geo-disasters often occur in karst regions during underground construction. In recent years, a number of shallow buried karst features have been discovered in eastern China. Survey boreholes show that karst caves exist at depths of 26-30 m and 33-36 m, which are typical of shallow buried karst. Using cross-hole seismic computed tomographic techniques, 36 geological anomalies consisting of 26 mud-filled caves, three empty caves, and seven fissure zones/loose lens bodies were detected. Most of the karst caves were oblate or oval. After determining the scale of and the connection between the caves, the study area was divided into two areas to provide advice on the treatment of caves during construction. An analysis of the development characteristics of the karst suggests that karst is controlled by several key factors, including topography, structural features, groundwater conditions, and human activities. Following an analysis of these factors and field studies of the process of formation of the shallow buried caves, solutions are proposed to prevent karst-related geo-hazards. The research results can be used in the design of foundations for buildings that are located in regions that include shallow buried karst in eastern China.