1D ANALYSIS OF LAND SUBSIDENCE IN SHANGHAI
1D ANALYSIS OF LAND SUBSIDENCE IN SHANGHAI
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发表时间：
2005
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影响因子：
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通讯作者：
J. Chai;S. Shen;H. Zhu;X. L. Zhang
中科院分区：
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作者：
J. Chai;S. Shen;H. Zhu;X. L. Zhang
对上海市地面沉降进行了调查。地面沉降主要是由于地下水的过量开采造成的，自1921年以来，在城市中心区的测量沉降为2至3米。采用一维有限元固结分析方法，对上海东部A点的沉降进行了模拟和预测。分析结果较好地模拟了实测沉降趋势，表明I弱透水层淤泥质粘土层、粉质粘土层和第三压缩层（II弱透水层）的压缩作用贡献了总沉降的80%左右。此外，它是数值计算表明，在含水层中的地下水位下降引起的固结，最终状态是一个稳定状态的水流向含水层，含水层以上的粘土层的导水系数的相对值有重要影响的计算量的沉降。此外，还假设了三种可能的情况来讨论未来的沉降。在保持2001年地下水位不变的情况下，50年的预计沉降量仅为2 mm左右。在地下水持续下降的情况下（IV和V含水层每年1 m，II和III含水层每年0.5 m，I含水层每年0.2 m），50年的预计沉降量约为1.25 m。如果在未来50年内所有含水层的地下水位恢复到零高程，则预测的升沉量约为0.20 m。
Land subsidence in Shanghai is investigated. The subsidence was mainly caused by excessive withdrawal of groundwater and since 1921, the measured subsidence was 2 to 3 m in the central area of the city. One-dimensional (1D) finite element consolidation analyses were conducted to simulate and predict the subsidence at Point-A, eastern part of Shanghai. The analysis result fairly simulated the field measured tendency and it indicates that the compression of the mucky clay layer, the silty clay layer in aquitard I and the third compression layer (aquitard II) contributes about 80% of the total subsidence. Also, it is shown numerically that for consolidation caused by groundwater level drawdown in an aquifer, the final state is a steady state water flow toward the aquifer, and the relative values of hydraulic conductivity of clayey layers above the aquifer have an important effect on calculated amount of settlement. Further, three possible scenarios were assumed for discussing the future subsidence. In the case of maintaining the groundwater level as it was in 2001, the predicted subsidence in 50 years is only about 2 mm. In the case of continuous drawdown of groundwater (1 m/year for aquifer IV and V, 0.5 m/year for aquifers II and III, and 0.2 m/year for aquifer I), in 50 years the predicted subsidence is about 1.25 m. If the groundwater level is recovered to zero elevation in all aquifers in the next 50 years, the predicted amount of heave is about 0.20 m..