临近既有线钢桁梁高空横移施工临时支墩安全性分析

为研究钢桁梁高空横移施工期间临时支墩的安全问题,基于考虑桩土共同作用的临时支墩整体有限元模型,对施工全过程进行模拟分析,利用现场实测结果对模型进行验证,并基于验证后的模型分析钢桁梁与滑道梁之间的内摩擦系数和桩长对施工全过程中临时支墩安全性的影响。分析结果表明:临时支墩沉降、墩顶水平位移和桩顶应变的模拟分析结果与实测结果吻合良好。内摩擦系数在规定取值范围内,对临时支墩沉降和桩顶应力的影响很小,但对墩顶水平位移的影响较为显著,两者之间基本呈正比关系。桩长变化对墩顶水平位移的影响较小,而临时支墩沉降和桩顶应变随桩长增加有明显的下降趋势。

Safety Analysis on Temporary Piers during Lateral Pushing Construction at High Attitude of Steel Truss Girder Approaching on Existing Railway Line

In order to study the safety of the temporary pier during the lateral pushing construction process of steel truss girder at a high altitude,the whole construction process is simulated and analyzed,based on the integral finite element model of temporary piers. The model is verified by field test results and the influence of friction coefficient and pile length on the safety of the temporary pier under construction is analyzed based on the verified model. The results show that the settlement of temporary pier,the horizontal displacement at the top of the pier and the strain at the top of the pile are well matched with the measurements. The friction coefficient within the specified range has little effect on the settlement of the temporary pier and the top stress of the pile,while the effect on horizontal displacement at the top of the pier is more significant,and the relationship between the friction coefficient and the horizontal displacement at the top of the pier is basically proportional. The variation of the pile length has little effect on the horizontaldisplacement at the top of the pier. With the increase of the pile length,the settlement of the temporary pier and the strain at the bottom decrease obviously.