摘要: |
为揭示桩端不同后注浆方式对灌注桩承载特性的影响,基于自行设计的压力注浆系统对三根位于均质黄土层的模型桩(S1、S2、S3)分别进行桩端开式、闭式及复合式注浆试验,并设置不注浆桩做对照,注浆结束10天后开展竖向抗压荷载试验。S1、S2、S3桩的总注浆量均为3 L,注浆压力均为0.3 MPa,注浆持续时间分别为33 s、47 s、44 s。试验结果表明:注浆后S3的承载力最大,3根桩的极限承载力分别提高144%、33.3%、411%;3根注浆桩距桩端约8倍桩径范围附近的侧阻均有增强,极限荷载下的增强比例分别为170.7%、39.5%、233.2%;静载试验完成后,挖出模型桩,观察浆液在桩侧和桩端的分布情况,发现S1、S2桩浆液沿桩侧上返,而S3桩除了有部分浆液沿桩侧上返,还有一部分浆液在桩底形成水泥扩大头。 |
关键词: 模型试验 桩端后注浆 注浆方式 承载特性 |
DOI: |
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基金项目:国家自然科学基金青年(51208294);山西省交通运输厅交通建设科技项目(2021-2-01) |
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Laboratory Model Test of Post Grouting Piles with Different Grouting Methods |
NIU Haoyu1, LI Yongsheng2, WANG Xu1, ZHOU Yalong1, LIU Xiaoyi1, LIANG Zhao1
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1.School of civil engineering, Lanzhou Jiaotong University;2.Taiyuan Northwest Second Ring Expressway Development Corporation
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Abstract: |
In order to reveal the influence of different post grouting methods on the bearing characteristics of cast-in-place piles, based on the self-designed pressure grouting system, the open-end, closed-end and composite grouting tests of three model piles (S1, S2 and S3) located in homogeneous loess layer are carried out respectively, and the non grouting piles are set as the control. The vertical compressive load test is carried out 10 days after the grouting is completed. The grouting volume of S1, S2 and S3 piles is 3 L, the grouting pressure is 0.3 MPa, and the grouting duration is 33 s, 47 s and 44 s respectively. The test results show that the bearing capacity of S3 is the largest after grouting, and the ultimate bearing capacity of the three piles is increased by 144%, 33.3% and 411% respectively; The lateral resistance of three grouting piles near the range of about 8 times of pile diameter from the pile end is enhanced, and the enhancement ratios under ultimate load are 170.7%, 39.5% and 233.2% respectively; After the static load test, dig out the model pile and observe the distribution of slurry on the pile side and pile end. It is found that the slurry of S1 and S2 piles returns up along the pile side, while for S3 pile, in addition to some slurry returning up along the pile side, some slurry forms a cement enlarged head at the pile bottom. |
Key words: 1aboratory model test post grouting pile grouting method ultimate bearing capacity |