北京东部地区地面沉降发育特征分析

Development characteristics of land subsidence in eastern Beijing

结合区域地质背景条件,利用水准测量、分层标地层变形、地下水位动态等监测数据,对北京东部地区地面沉降的发育特征与发展变化规律进行了分析研究。该区域的地面沉降与地下水开采具有显著相关性,深部地层仍是沉降的主要贡献层位;沉降中心地下水具有明显的分层变化规律,深层承压水明显的水位降落漏斗,直接导致深部地层沉降压缩最为显著;地面沉降的区域分布、沉降速率变化与地下水降落漏斗具有一定的时空相关性;南水北调的稳定供水,有效缓解了北京地面沉降快速发展的趋势。

The evolution of land subsidence and variation of groundwater as well as the spatial-temporal correlation between land subsidence and groundwater dynamics in eastern Beijing were investigated in the context of regional geology by using leveling survey,layer-wise monitoring data of land subsidence monitoring stations,and groundwater dynamics monitoring data.The contribution of the land subsidence regions in eastern Beijing to the total land subsidence was significantly correlated to the change in the groundwater exploitation horizon therein,with deep strata remaining the main contributor of subsidence.The groundwater variation in the subsidence center was distinctly stratified,with obvious depression cones existing in deep confined water,which directly accounted for the most obvious subsidence compression in the deep strata.A spatial-temporal correlation existed between the distribution and subsidence rate variation of land subsidence regions and depression cones.The stable water supply caused by the South-to-North Water Diversion initiative has been effective in easing the rapid expansion of land subsidence in Beijing.