深层地下水回灌对高架桩基长期沉降的影响

以上海地区高架道路桩基础为例,采用控制地下水流量的流-固耦合方法分析了季节性变化的地下水开采及回灌作用下的桩基长期沉降特征.数值分析表明,地下水的季节性抽灌使得高架及大地变形发生波动性变化,区域地面沉降略小于高架沉降,但变形趋势一致.采用流-固耦合方法对上海地区典型高架桩基实例进行数值模拟,所得分析结果与实测结果基本吻合,高架桩基在上部荷载和深层回灌耦合作用下出现隆沉变化,其长期沉降受深部土层隆沉位移的影响更大.通过分析回灌参数,得到深层回灌荷载影响高架桩基变形的基本规律,为高架桩基长期沉降的预测分析提供了参考.

Effect of Deep Underground Water Recharge on Long Term Settlements of Pile Foundations

Abstract： Artificial recharge in deep strata is an effective method to prevent land subsidence, and make the deep strata upheave to some extent. The pile foundations of elevated road are relatively deep so that the deformation of deep strata will greatly affect the elevated road. Using the numerical method, the elevated pile and the behavior of the surrounding soil at pumping and recharge loads were simulated and its deformation characteristics were discussed based on the coupled theory. The result shows that groundwater pumping can cause a large settlement of elevated road, while the artificial recharge can control the settlement effectively. Regional land subsidence is smaller than the elevated settlement, but the deformation tendency matches the elevated road well. Besides, based on an engineering project, the long term deformation characteristic of elevated road at underground water recharge was simulated. The study shows that numerical results agree with the filed data, and the deformation characteristics of elevated piles are mainly influenced by deep strata. Using parameter analysis, the basic laws of elevated deformation were obtained, providing reference for the prediction of long term settlement of elevated piles.