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桩承式加筋路堤在高速公路软基处理中得到了广泛应用,但目前对其承载变形机制还缺乏深刻认识。结合南京长江第四大桥北接线段软基加固工程,基于数值方法对现浇X形桩桩承式加筋路堤中桩土沉降、桩土应力、桩身轴力及超静孔隙水压力的发展变化规律进行了分析。研究结果表明,受土拱效应影响,路堤填筑荷载主要由桩体承担,桩及桩间土土压力在路堤填筑过程中均逐渐增大,在软基固结过程中,桩顶土压力继续增大而桩间土土压力逐渐减小,最终趋于各自的稳定值;路堤填筑过程中桩身轴力增长较快,现浇X形桩桩身上部较大部分区段存在负摩阻力,桩身中性点位置经历了先逐渐上移、而后向下移动,最终趋于稳定的过程。
Pile-supported reinforced embankments have been widely used in soft foundation treatment of expressways, but there is a lack of deep understanding of the bearing deformation mechanism. Based on the numerical simulation of soft foundation consolidation in the fourth connecting section of Nanjing Fourth Yangtze River Bridge, the development of pile-soil X-ray pile embankment, pile-soil stress, pile axial force and excess pore water pressure The change rule is analyzed. The results show that under the influence of soil arching, the embankment filling load is mainly borne by the pile body, and the earth pressure of the pile and the piles is gradually increased during the embankment filling process. During the soft foundation consolidation process, The pressure on soil between the piles gradually decreased and eventually reached their respective stable values. The axial force of the pile increased rapidly during filling of the embankment, and there was a negative friction in most of the upper part of the cast-in-situ X-shaped pile Resistance, pile neutral position has gone through a gradual upward move, and then down to eventually stabilize the process.