THE CHARACTERISTICS, CAUSES OF GEOLOGICAL DISASTERS AND PREVENTION OF SHALLOW COVERED KARST AT A TUNNEL SECTION OF THE WUXI METRO, JIANGSU PROVINCE, CHINA

In recent years, in the process of urban construction in Wuxi, geological hazards caused by covered karst have become more and more problematic. In this paper, based on the covered karst in the foundation of a section of Wuxi Metro, the karst development in the site is detected by using the cross-hole seismic CT technique. It is found that:(1)there are many karst caves in the site, the scale is generally small, and the buried depth of the caves varies greatly; (2)The karst caves in the site often penetrate with the Quaternary strata, and the connectivity and water-richness of the karst caves are better between karst caves. The roof rockmass of karst caves has low strength and poor stability, which has a great impact on engineering construction; (3)According to the shape, development position, filling state and filling type of caves, this paper divides the caves into five types. In view of these five different types of caves, combined with the engineering geological conditions of the site, the geological disasters are studied and analysed, and corresponding prevention and control measures are given. This study has certain reference and guiding significance for the construction design of the proposed subway tunnel.