上海地面沉降计算
Computation of Land Subsidence in Shanghai
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摘要: 上海地面沉降是通过一维基本固结方程和拉普拉斯变换进行计算的。它基于下列论断:①经典固结理论的有效性;②叠加原理在含水层边界水位条件分析中的适用性;③周期荷载下,土的双线性模型的可取性。本文分析指出,地面沉降现象可用地下抽水作用引起土层内应力重分布和由此导致的变形作合理的解释。将1965~1978年间的超静水压力和变形计算值同实测值作了比较,结果令人满意。此分析也为把地下水回灌作为控制沉降的一个有效措施提供了有力的理论依据。Abstract: Computations of land subsidence in Shanghai are carried out by employing the basic one-dimensional consolidation equation and the Laplace transformation. They are based on the inferences: (1) validity of the classical consolidation theory; (2) validity of superposition theorem of boundary water level conditions in aquifers; and (3) adaptability of bi-linear model under cyclic loading. Analysis shows that the phenomena of land subsidence can be well interpreted by stress redistribution and its consequent deformation occurred in the soil layer as a result of subterranean pumping. The comparisons from 1965-1978 between the computed and actually measured data on hydrostatic excess pressures and deformations are good. This analysis also provides a sound basis for suggesting groundwater recharging as an effective means to control the subsidence.