立柱桩在深基坑分步开挖过程中的上拔位移分析

Uplift displacement of soldier piles during stepped excavation of deep foundation pits

基于对坑底地基卸荷应力与回弹变形的新认识和一种可考虑桩间土承受附加荷载与变形的广义荷载传递法,提出了深基坑立柱桩因开挖而隆起的分析方法。该方法可考虑立柱桩的变截面特性以及分步设撑、开挖的施工工况,可分析桩土之间的荷载传递特性。由于支撑立柱桩容易实施位移观测,立柱桩的分析结果便于与实测结果比较,为分析方法的完善、计算参数的合理选取提供基础。通过和2个工程实例对比,验证了用本方法计算立柱桩在开挖过程中受力及位移的合理性,同时对计算值与实测值的差异原因进行了讨论。

Based on the new understanding about rebound stress and deformation at the bottom of deep foundation pits and the generalized load transfer method considering the additional load or deformation of the soil around piles, an analytical method is proposed for the uplift of soldier piles due to excavation. It can take many factors into account, e.g., variable cross-section character of soldier piles, installation and stepped excavation of strut system arid construction situation, and it can be employed to analyze the load transfer behaviors of soldier piles. Because the uplift dis^a~cement of the soldier piles is easily monitored, the calculated results are easily compared with the measured ones, which can improve the method itself and the parameters to be chosen more reasonably. Through two cases, the rationality of the proposed method to calculate the uplift displacement of soldier piles is validated. The difference between the calculated and the measured values is also discussed.