桩端后注浆灌注桩承载能力增强机理试验研究
PDF下载 (241)张 恒,刘干斌,周 晔,韩 仲.桩端后注浆灌注桩承载能力增强机理试验研究[J].宁波大学学报(理工版),2021,34(4):72-78.DOI:
ZHANG Heng,LIU Ganbin,ZHOU Ye,HAN Zhong.Experimental study on enhancement mechanism of bearing capacity of base post-grouting cast-in-situ pile[J].Journal of Ningbo University(Natural Science & Engineering Edition),2021,34(4):72-78.DOI:
| Title: | Experimental study on enhancement mechanism of bearing capacity of base post-grouting cast-in-situ pile |
| 作者: | 张 恒, 刘干斌, 周 晔, 韩 仲 |
| Author(s): | ZHANG Heng, LIU Ganbin, ZHOU Ye, HAN Zhong |
| 关键词: | 桩端后注浆; 灌注桩; 自平衡加载 |
| Keywords: | pile base post-grouting; cast-in-situ pile; self-balanced loading |
| 分类号: | TU473 |
| 文献标识码: | A |
| 摘要: | 为进一步研究灌注桩桩端后注浆承载机理, 对宁波某施工场地的4根灌注桩开展了现场试验研究. 4根灌注桩均采用自平衡方式加载, 以加载方式获得每根桩的Q—s曲线, 并通过桩身内部埋设的传感器得到加载期间桩身及桩底的应力数据, 根据应力分析研究桩身弯矩及桩侧摩阻力的变化. 测试结果表明: 桩端后注浆能提高钻孔桩竖向极限承载力约20%; 注浆期间, 桩侧摩阻力的重新分布使桩身轴力发生较大变化, 且桩端承受弯矩会对桩体结构造成一定破坏; 加载期间, 注浆桩的桩端部分承载力主要由桩侧摩阻力提供, 而非注浆桩的桩端部分承载力主要由端阻力提供; 在透水地层中, 桩承载力的提高依赖于桩侧摩阻力的影响, 而在不透水地层中扩大头的产生也会成为影响因素. |
| Abstract: | Field tests were performed on 4 cast-in-situ piles at a construction site in Ningbo in order to further study the bearing mechanism of post-grouting cast-in-situ pile. The four piles were all loaded by self-balanced method. Q—s curve of each pile was obtained by loading, and the stress of pile body and pile base during loading was measured by embedded sensors. According to stress analysis, the changes of bending moment and skin frictional resistance of pile were studied. The results show that the base post-grouting technique can increase the vertical ultimate bearing capacity by about 20%. During grouting, the redistribution of skin frictional resistance causes the axial force changing drastically, and the bending moment may lead to certain damage to the structure. During loading, the bearing capacity of the grouting pile base is mainly provided by the skin frictional resistance, while that of the non-grouting pile base is mainly provided by the base resistance. In permeable strata, the enhancement of pile bearing capacity depends on the influence of skin frictional resistance, and the generation of enlarged heads may turn to be an influencing factor as well. |
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| 备注/Memo: | 收稿日期: 2020－06－04. 宁波大学学报（理工版）网址: http://journallg.nbu.edu.cn/ 基金项目: 浙江省基础公益研究计划项目(LGF20E080012）. 第一作者: 张恒（1996－）, 男, 浙江宁波人, 在读硕士研究生, 主要研究方向: 软土地下结构. E-mail: 1123377498@qq.com* 通信作者: 刘干斌（1976－）, 男, 江西吉安人, 教授, 主要研究方向: 土结构动力相互作用. E-mail: liuganbin@nbu.edu.cn 宁波大学学报（理工版）网址：http://journallg.nbu.edu.cn/ |
