STUDY ON GROUND COLLAPSE RISK ZONATION IN DOWNTOWN SHANGHAI

Shanghai is located in the alluvial plain of the Yangtze River Delta. The Huangpu River and the Suzhou River flow through the central urban area. The unique geographical environment and sedimentary environment have formed the shallow sand layers in Shanghai. Due to the large-scale development of urban construction, in addition to aging underground pipelines in the urban center, the risk of quicksand sharpens, which further results in the ground collapse. Based on the identification of key elements of ground collapse, in this paper, a risk assessment system on ground collapse was established, in which both hazard and vulnerability were introduced. Further analysis was made on the characteristics of ②3 silty soil, the structural defects of underground pipelines and the scale of underground space. In this paper, the evaluation of hazard and vulnerability factors were quantified by a fuzzy evaluation model and the risk of ground collapse was studied in Shanghai city center. This study aims to provide technical support for the establishment of surveillance network to monitor an area of interest in time, offer basis for decision making in land resources management, city construction, municipal engineering, and environmental protection. Study findings also makes sense in providing demonstration of ground collapse prevention and risk management.