吴江盛泽地区建筑荷载和地下水开采对地面沉降的影响

Influence of Building Load and Groundwater Exploitation on Land Subsidence in Shengze,Wujiang

为了准确分析建筑荷载和地下水开采对地面沉降的影响,为吴江盛泽地区科学防控地面沉降提供决策依据,基于比奥固结和地下水渗流理论,建立了建筑荷载和地下水开采与地面沉降三维全耦合有限元数值模型,分别模拟预测了在建筑荷载单独作用、地下水开采单独作用及建筑荷载和地下水开采叠加作用三种情况下,2015-09-01—2030-08-31盛泽地区逐年地面沉降变化趋势。结果表明,建筑荷载对盛泽地区地面沉降的影响大于地下水开采。第Ⅰ黏性土弱含水层和第I承压含水层分别为建筑荷载和地下水开采单独作用下的主压缩层,单层压缩量占比分别为43.04%和54.06%;第Ⅰ承压含水层及其上覆第Ⅰ黏性土弱含水层是二者叠加作用引发土体变形的主压缩层,其压缩量之和占总压缩量的71.30%。建筑荷载和地下水开采单独作用下引发的地面沉降量的线性叠加之和大于二者叠加作用下引发的地面沉降量,建筑荷载和地下水开采叠加作用引发的地面沉降具有耦合效应。

In order to provide decision-making basis for prevention and control of land subsidence in Shengze of Wujiang,the authors analyzed the influence of building load and groundwater exploitation on land subsidence.Based on the Biot’s consolidation theory and ground water seepage theory,a threedimensional fully coupled mathematical model of building load,groundwater exploitation on land subsidence was established.By using this model,the trend of land subsidence was simulated from 2015-09-01 to 2030-08-31 under the conditions of only building load,only groundwater exploitation,and the superposition of building load and groundwater exploitation.According to the prediction results,the effect of building load on land subsidence in Shengze is greater than that of groundwater exploitation.With the first weak clayed soil aquifer and the first confined aquifer as the main compressible layers,under the individual action,the single-layer compression accounted for 43.04%and 54.06%respectively;while with the first confined aquifer and its overlying weak clay soil aquifer as the main compression layer of the superposition of the building load and the groundwater exploitation,the total compression amount accounted for 71.30%of the total compression.The sum of the linear superposition of ground subsidence caused by the building load and groundwater exploitation alone is larger than the ground subsidence caused by the superposition of the two.The land subsidence caused by the superposition of the building load and the groundwater exploitation has a coupling effect.