摘要
目的探讨复杂巨厚松散沉积层以控制地面沉降为目标的最优化深基坑降水设计理论.方法以上海地铁四号线董家渡段隧道修复基坑降水为例,根据基坑降水过程中有效应力和孔隙水压力的转化关系,建立了深基坑降水三维渗流与地面沉降的耦合模型,并采用有限差分数值模拟方法,模拟了在多层含水层复合存在、含水层最深底板埋深达145 m、基坑周围挡水连续墙埋深达65 m,基坑中心下伏第Ⅰ承压含水层上部降压段水位降至埋深40 m时的地下水复杂流动状态及其地面沉降特征.结果得出了抽水井埋深达59 m、抽水井过滤器埋深为44至59 m,30口抽水井联合抽水的坑内优化降水方案.结论深基坑降水三维渗流与地面沉降耦合数值模拟用于复杂巨厚松散沉积层深基坑降水优化设计具有较高的可信度,此类地区采用坑内降水可有效控制基坑周围地面沉降的发生.
The optimal designing theory of deep foundation pit dewatering for controlling land subsidence was discussed in loose sediment with great thickness and complex characteristics. According to the relationship between effective stress and pore water pressure, a coupling model between three-dimensional seepage of deep foundation pit dewatering and land-subsidence was established and applied to foundation pit dewatering at Dongjiadu part of subway line 4 in Shanghai, and the complicated flow state of groundwater and land-subsidence characteristics were simulated by three-dimensional finite difference method under the conditions that the aquifers were deposited layer by layer, the bottom of the aquifers went deep to 145m, the horizontal flow barrier went deep to 65m, and the ground water level of the upper part of confined aquifer Ⅰ under the center of foundation pit was decreased to 40.00m under land surface. Consequently, an optimal scheme was achieved, in which the pumping wells penetrated to 59m, while the filters of the pumping wells were located between 44m to 59m, with thirty pumping wells operated at the same time. Finally, it is concluded that it is reliable to use the coupling numerical simulation between three-dimensional seepage of deep foundati on pit dewatering and land-subsidence to design the optimal scheme of deep found ation pit dewatering in loose sediment with great thickness and complex characteristics, and it is effective to use the method to dewater the foundation pit so as to control the land-subsidence surrounding the foundation pit..
出处
《沈阳建筑大学学报（自然科学版）》
EI
CAS
2007年第1期47-51,共5页
Journal of Shenyang Jianzhu University：Natural Science
基金
上海市重大科研基金项目(04dz12003)
关键词
松散沉积层
深基坑降水
地面沉降
数值模拟
loose sediment
deep foundation pit dewatering
land subsidence
numerical simulation
