后压浆桩抗压与抗拔现场对比试验

随着建筑高度不断突破,其基桩承载力越来越大,可以通过成桩后压力注浆方式满足抗压和抗拔承载力的高要求。通过对后压浆法钻孔灌注桩进行现场抗压与抗拔的对比试验,对后压浆法施工钻孔灌注桩力的传递机理进行研究,对比分析了抗压桩与抗拔桩桩周摩擦力与承载能力的差别,明确了抗压桩与抗拔桩荷载传递路径与桩在破坏过程中力的发挥方式。研究表明:桩端与桩侧压浆技术提高了桩端的承载力与桩周的桩-土摩擦力,运用桩侧压浆技术使得桩在发挥效应时存在一种机械咬合力,增加了桩的竖向承载力,尤其是提高了抗拔桩的承载力。研究结果为以后更进一步研究在不增加桩长条件下利用机械咬合力提高抗拔桩承载力提供参考。

Field Comparative Test of Compressive and Uplift Behavior of Post-grouting Pile

The demand for high bearing capacity posed by compressive load and uplift load on foundation pile can be addressed by pressure grouting. By conducting compressive test and uplift test on post-grouting piles, we studiedthe mechanism of load transfer on post-grouting piles, and compared the differences in side friction and bearing capacityof piles between compressive test and uplift test. We also identified the load transfer paths and the approachesof compressive force and uplift force in the failure process. Research result indicates that pressure grouting technologyimproves the bearing capacity of pile and the friction between pile and soil; moreover, a mechanical interactionis produced by pressure grouting, which also enhances the bearing capacity of pile, in particular, the uplift pile.The results offer reference for researches on improving the bearing capacity of uplift pile without increasing the pilelength.