中文摘要：

在天津地区几个场地开展了承压含水层抽水试验,观测到承压含水层局部降压过程中其上覆土体出现'上小下大'的沉降规律,其下卧土体出现隆起现象。采用考虑降水井瞬态降水的三维流固耦合数值模型的分析进一步表明,承压含水层局部而不是大面积降压过程中其上覆弱透水土层在没有产生明显水位下降时,可产生'土拱效应',土拱区内部土体出现附加拉应力,进而发生张拉变形;而承压含水层下卧土体的隆起则是由于下卧弱透水层中地下水向上渗流产生的渗流力所致。进一步地分析了不同竖向补给条件及不同场地条件的承压含水层长期局部降压过程中土体沉降规律,揭示了不同情况下承压含水层局部降压引起的土体最大沉降位置。不论承压含水层竖向补给条件如何,不论承压含水层短期降压还是长期降压,当上覆弱透水层的渗透系数在其特征范围内变化时,对承压含水层进行局部降压,其上土层中最大沉降位置均出现在有水位降深的土层顶板处。由于分层总和法不能考虑成层土中承压含水层局部降压时其上弱透水土层的空间效应,若基于单井或小范围群井抽水试验反演沉降经验系数,并采用分层总和法分析不同深度土层沉降时,将导致承压水局部降水引起的地表以下土体的沉降被低估。

英文摘要：

By carrying out the in-situ pumping tests on confined aquifer in Tianjin, it is found that the settlement of soils of overlying confined aquifer gradually increases up to down during local relieving, meanwhile, heave appeares in underlying soils. Further analysis, by using three-dimensional fluid-solid coupling numerical model, indicates that the soil-arch effect will form in soils, which has no drawdown and overlies confined aquifer during its local relieving, in the meantime, the additional tensile stress and tensile deformation appeare there, and moreover, the seepage force is the reason why the soils underlying the confined aquifer heave. Furthermore, the law of ground movement induced by long-term local pressure-relief of confined aquifer under different water supplies and site conditions is studied, and the location of the maximum soil settlement under each condition is obtained. The maximum soil settlement appears at the top of stratum which has drawdown under arbitrary water supply conditions, relieving time and permeability ranges of the overlying aquitard. Because the spatial effect of the overlying soils of confined aquifer induced by local pressure-relief of the confined aquifer cannot be taken into account using the layering summation method (LSM), it will underestimate the settlement of soils below the ground surface during its relieving if LSM is adopted based on the settlement correction factor derived from the pumping tests.