中文摘要：

本文采用理论分析的途径，探讨了抽降水引起桥梁桩基沉降的机理，推导了由于降水引致的层状土对桩基负摩擦力的理论计算公式，并通过迭代法计算得到实际的中性点位置以及总的负摩擦力大小。在以上分析基础上，建立了在抽降水情况下桥梁桩基沉降的理论计算方法。本文利用该方法对某高速铁路桥墩桩基在大量抽水情况下的沉降值进行了计算，计算结果与实测值相差5．7mm，相对误差仅13％，计算结果验证了该方法的可行性。

英文摘要：

Through theoretical analysis, the settlement mechanism of bridge pile foundation caused by dewatering was examined in this paper. A theory formula of negative friction applying to layered soils was derived. Tthe neutral point and total negative friction were abtained by using the iteration method. A method for computing piles settlement under this condition was put forward. The method was used to calculate the pile foundation settlement of bridge for a high-speed railway, which was resulted from dewatering by pumping groundwater. The calculated settlement was also compared with the measured settlement. The results show that their difference was 5. 7mm, and the relative error was 13 % , indicating that the proposed method is reliable.