上海市承压含水层系统应力-应变特征及地面沉降防治对策

1990年以来，上海市地下水开采与人工回灌格局发生了较大的变化。承压含水层地下水位变化与压缩变形均表现为新的特点与发展趋势。通过对上海中心城区含水层系统的应力一应变特点分析，总结了承压含水层随地下水位下降所表现出的弹性一弹塑性一塑性变形的演化规律。上海中心城区第Ⅱ、Ⅲ承压含水层总体上处于地下水开采与人工回灌的平衡状态，表现为弹性变形；而第Ⅳ、Ⅴ承压含水层由于地下水位目前已严重低于其“临界水位”，表现为持续压缩的塑性变形。目前，第Ⅳ承压含水层对中心城区地面沉降贡献率已达到了49．3％，西部华漕地区第Ⅴ承压含水层变形的贡献率为46．7％。针对各承压含水层不同的变形特点，提出了地下水资源管理与地面沉降防治对策。

Stress-strain characteristics of the confined aquifer system and land subsidence controlling countermeasures in Shanghai

Since 1990, some new characteristics and trends of the confined groundwater aquifers for the critical groundwater level and compaction have occurred as a result of the change of groundwater exploitation and artificial injection patterns. By analyzing the stress-strain properties of the confined aquifer system of the Central Shanghai City, the authors discussed the significance of elastic, elastic-plastic and plastic deformations of the confined aquifer system corresponding to the drop of the groundwater level. The result indicated that the 2~(nd) and 3~(rd) confined aquifers were characterized by elastic deformation, showing the balance between groundwater exploitation and artificial injection. In contrast, the 4~(th) and 5~(th) confined aquifers were featured with continuous plastic deformation, revealing the groundwater levels are far below the critical water level. Up to now, the contribution of the 4~(th) confined aquifer to land subsidence has increased to 49.3%, and that of the 5~(th) confined aquifer in western Huacao area has arrived to 46.7%. On the basis of the different deformation characteristics, some management countermeasures are put forward for controlling land subsidence.