抽排水时间对静钻根植排水桩承载特性的影响

Influence of Drainage Time on Bearing Characteristics of Static Drill Rooted Drainage Pile

为了研究真空负压抽排水时间对静钻根植排水桩承载特性的影响,开展了多组不同抽排水时间情况下静钻根植排水桩和静钻根植桩模型试验,对比测试了孔压发展变化和不同阶段的桩基承载力。结果表明:抽真空过程中,排水桩桩周孔压在前8 h内消散速率较快,随后逐渐变缓;相较于静钻根植桩,真空负压抽排水3、8、72 h后28 d,静钻根植排水桩桩基的极限承载力分别提高了56%、61%、74%,抗变形能力分别提高了10.2%、89.8%、124.5%。抽排水能够显著加快水泥土固化时间,提高桩周土体强度特性,进而提高静钻根植排水桩的承载力和抗变形能力,因此具有较好的推广价值。

The aim of this research is to investgate the influence of pumping and drainage time on the bearing characteristics of static drill rooted drainage pile.Several groups of model tests of static drill rooted drainage pile and ordinary static drill rooted pile were performed with pumping and drainage time as the variable to compare the change of pore pressure and the bearing capacity of pile foundation at different stages.Results show that in the process of vacuum-pumping,the pore pressure around drainage pile dissipates rapidly within the first eight hours,and then slows down gradually.Compared with that of ordinary static drill rooted pile,the ultimate bearing capacity of drainage pile foundation after vacuum negative pressure pumping and drainage for 3 hours,8 hours,and 72 hours,increases by 56%,61%,and 74%,respectively,and the anti-deformation ability increases by 10.2%,89.8%and 124.5%,respectively.Pumping and drainage has a good popularizing value as it significantly accelerates the cement-soil solidification,improves the mechanical properties of soil around the pile,and then enhances the bearing capacity and anti-deformation capacity of the pile foundation.