刚性桩加固软土路基竖向土拱效应的试验分析

刚性桩加固软土路基填土在自重作用下形成竖向土拱并通过土拱传递荷载,浅层荷载传递机制直接影响到桩土协调工作和加固效果,但目前对竖向土拱效应以及土拱的特性仍然缺乏深入研究。利用设置试验段进行现场试验,对采集到的路基孔隙水压力和桩土相对位移数据进行分析处理,从应力和变形两方面验证了刚性桩竖向土拱的存在性。试验数据分析反映,一定的荷载对应一定的土拱力学平衡结构;在现场试验条件下土拱形成后,荷载每增加约20kPa,土拱破坏一次,而后重新形成;粗骨料填土材料形成的土拱稳定性较好,加桩帽形式的土拱效应更为显著。

Experimental analysis of vertical soil arching effect of embankment reinforced by rigid piles

A soil arch would be generated in the expressway embankment reinforced by rigid piles under the dead weight of the fill, and the external load could be transferred through the arch. The load transfer mechanism of the shallow layer directly influenced the coordination work of piles and soil and the effect of reinforcement. However, research on vertical soil arching effect and character of soil arch was not well enough. By experiment in situ and analysis on the data of the pore water pressure and the pile-soil relative displacement, the existence of the soil arch was approved. The experimental data also reflected that certain equilibrium mechanical structure was formed under given load. Every time the load was increased by 20 kPa, the original structure was destroyed once and then generated again. The data also reflected that the arch generated in coarse aggregate could bear more load increment and the arching effect was stronger when the embankment was reinforced by piles with caps.