北京地面沉降控制区划及防控措施

Control zoning and prevention measures on land subsidence in Beijing

地面沉降区划是地面沉降防控的基础性工作和措施制定的重要依据.目前北京区域平均地面沉降速率呈减缓趋势,但沉降中心年沉降速率依然较大.为实现地面沉降的全面有效控制,在综合比较地面沉降易发性分区、危险性分区和风险分区等区划评价指标和体系后,基于评价指标精简而典型、评价数据易获取、评价体系实用易操作的评价原则,建立了北京地面沉降控制分区的评价体系和分级标准.利用地面沉降发育程度分区和危害程度分区的GIS(Geographic Information System)叠加,将北京地面沉降区分为三级控制区,进行分区域差别化防控.一级控制区为地面沉降重点控制区,从城市规划、地下水管理、工程施工降水、地面沉降监测等方面提出了每一级控制区内的地面沉降防控措施,以期为政府的地面沉降防控决策提供技术支持.

The zoning map of land subsidence is the basis for its prevention and control. The main cause of land subsidence in China is excessive extraction of groundwater. The control zoning on land subsidence can not only help to devise targeted strategies,but also promote the optimal management of groundwater exploitation. At present,the annual average rate of regional land subsidence in Beijing is slowing down,but the annual rate is still faster at several subsidence centers. Based on comprehensively consideration of the evaluation indexes and methods of its susceptibility zoning,hazard zoning and risk zoning,the evaluation principle and method of land subsidence control zoning in Beijing are established. First,the development degree zoning and hazard degree zoning on land subsidence are prepared. Then,the control zoning map is received from the overlay of these two maps. Finally,the control area of land subsidence in Beijing is divided into three levels. The prevention and control measures in each level of land subsidence control area are formulated from the aspects of urban planning,groundwater management,construction precipitation and land subsidence monitoring. Level I Control Zone is a focus area which is subject to the most strenuous regulations. The results of this study could provide technical support for the government’s decision-making on land subsidence prevention and control.