基于降水优化方案的基坑地面沉降数值模拟

Numerical Simulation of Land Subsidence of Deep Foundation Pit based on Dewatering Optimization Schemes

针对深基坑降水引起地面沉降给周边环境带来的问题,基于最优化法的降水设计方案,以地下水动力学原理和耦合固结理论为基础,建立地下水渗流场和应变场耦合数学模型。以某地长江大桥锚碇基坑为例,采用有限差分数值分析法求解,模拟得到最优化降水的渗流场和地面沉降量,以及地面沉降主要影响因素的影响程度。模拟结果表明,基于最优化法降水设计能够达到设计要求,产生的长江大堤沉降量较小,其中渗透系数的变化对地面沉降影响较大,长江定水头边界和基坑防渗墙一定程度上减小了地面沉降量。

Aiming at the problems by land subsidence owing to deep foundation pit dewatering, using the optimization dewatering design schemes , on the basis of groundwater dynamics theory and coupling con- solidation theory ,the coupled mathematical model of groundwater seepage field and strain field is estab- lished. As the anchor foundation pit of Yangtze River Bridge for example, the seepage field and land sub- sidence amount of optimization dewatering are simulated and the influencing degree of land subsidence is also analyzed using finite difference numerical method. The results show that it can meet the design re- quirements, the subsidence amount of Yangtze River bank is reduced, the change of permeability coeffi- cient is the first factor that causes land subsidence, and the boundary of constant head and the seepage wall are set up as to as decrease the pumpage, the land subsidence would further reduce.