路堤荷载下筒桩复合地基沉降的改进算法
Improved solution for predicting settlement of tubular-pile composite ground
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摘要: 常规的筒桩复合地基沉降计算方法不考虑桩身和桩间土荷载分布形式对地基附加应力的影响,且无法考虑桩身与桩间土的差异沉降。针对路堤荷载作用下的筒桩桩网复合地基,基于Mindlin解分别推导了桩端阻力、桩外侧及内侧摩阻力所产生的附加应力;同时运用Boussinesq解给出了路堤荷载作用于桩间土产生的附加应力。此即用于计算筒桩桩网复合地基附加应力场的M-B联合算法,此法可较合理考虑路堤加荷过程中桩身和桩间土体的差异沉降。最后,通过工程实例分析,将此方法所计算的沉降值与现场实测结果进行对比,结果显示两者基本吻合。Abstract: The traditional methods for settlement calculation of composite foundation are unable to consider the effect of load distribution of piles and soils. The differential settlement between the piles and the soils is also difficult to be predicted by these methods. This study concerns the additional stresses in tubular pile-net composite ground induced by embankment load. Based on the Mindlin’s solution, the additional stresses caused by pile end resistance, pile shaft resistances inside and outside the pipe are deduced, respectively. The Boussinesq’s solution is also used to obtain the additional stress in the soils surrounding the piles. Such improvement that incorporates the Mindlin’s and the Boussinesq’s solutions is expected to offer better prediction of the differential settlement between the piles and the soils in the tubular-pile composite ground. Finally, the new approach is applied to a case history, and the predictions seem to agree with the measurements fairly well.