北京平原区地面沉降水准监测网点位优化

长期超量开采地下水所诱发的地面沉降已经成为北京平原区最主要的地质灾害。文中针对现有水准监测网点位布设存在的不足,分别选取水文地质单元分区、主要开采层地下水位下降速率、可压缩层总厚度3类影响要素图件,基于GIS空间分析平台,划分北京平原区地面沉降综合影响因素分区,共划分448个分区。在此基础上,进行地面沉降水准监测网点位优化设计,新增水准点220个。同时,采用地质统计学中克里金插值误差的方差作为精度评价指标,分别绘制监测网优化前后标准差分布等值线图,发现优化后的标准差明显小于优化之前,证明以地质环境背景为依托,利用地面沉降综合影响因素分区图进行水准监测网点位优化设计的方法是可行的,可以作为今后地面沉降监测点布设的基础依据。

Optimization design of land subsidence levelling network of Beijing Plain

Land subsidence induced by long-term excessive groundwater withdrawal has constituted a major geological disasters in Beijing plain. This paper is based on the deficiency of present leveling network, selected three kinds of influence factors, including the partition of hydrology geology unit, the groundwater level decreased rate of main exploitation layers and the total thickness of compressed layers. Based on GIS spatial analysis platform, the partition map of comprehensive affecting factors of Beijing plain is created, and divided into 448 partitions. On this basis, we optimized design the land subsidence leveling network, added 220 leveling points. Using geostatistical Kriging interpolation error variance as the accuracy evaluation index, we drew the standard deviation distribution contour map of land subsidence leveling network, found that the standard deviation of the optimized is lower than before. Proved that based on the background of geological environment, using the partition map of comprehensive affecting factors to optimize design the land subsidence leveling network is feasible. This method can be used as the basis of construction of leveling points.