基于BOTDA光纤传感技术的螺旋挤土灌注桩承载特性现场试验

发布时间：2018-06-01 04:39

本文选题：螺旋挤土灌注桩 + 分布式光纤　；参考：《中南大学学报(自然科学版)》2017年03期

【摘要】：为了研究螺旋挤土灌注桩(SDS桩)的荷载传递规律及承载特性,将基于布里渊光时域分析(BOTDA)原理的光纤传感技术用于螺旋挤土灌注桩桩基检测,在某工地进行现场试验,测得试桩加载过程中的桩身应变,进而得出桩身轴力、桩侧摩阻力及桩端阻力,并与同一场地内长螺旋灌注桩(CFA桩)的测试结果进行对比分析。研究结果表明:分布式光纤测量可以方便地获取桩体的荷载传递规律;同一桩顶荷载等级下,SDS桩桩端阻力比CFA桩的小,达到极限荷载时,桩端阻力约占总荷载的8%,设计时SDS桩可按摩擦桩或端承摩擦桩考虑;相同桩体参数和地层条件下,与CFA桩相比,SDS桩的极限承载力提高了约67%,相同桩顶荷载作用下,桩体沉降也比CFA桩的小;SDS桩成桩过程中通过桩周土体的物理挤密和应力状态的改变促进了侧摩阻力的大幅提高,从而承载力得到显著提升。
[Abstract]:In order to study the load transfer law and load bearing characteristics of spiral compaction pile (SDS pile), the optical fiber sensing technology based on Brillouin optical time domain analysis (BOTDA) principle was used to detect the pile foundation of spiral soil compaction pile, and the field test was carried out at a site. The strain of the pile during loading is measured, and then the axial force, friction and tip resistance of the pile are obtained, and the results are compared with those of the CFA pile with long spiral cast-in-place pile in the same site. The results show that the load transfer law of pile body can be easily obtained by distributed optical fiber measurement, and the resistance at the end of CFA pile is smaller than that of CFA pile under the same pile top load grade. The resistance at the end of the pile is about 8% of the total load. In design, the SDS pile can be considered according to the friction pile or the end bearing friction pile, and the ultimate bearing capacity of the CFA pile is increased by about 67 when compared with the CFA pile under the same pile body parameters and stratum conditions, and under the same pile top load, The settlement of the pile also promotes the increase of the lateral friction greatly through the change of the physical compaction and stress state of the soil around the pile during the forming process of the small CFA pile, thus the bearing capacity is improved significantly.
【作者单位】：东南大学岩土工程研究所;江苏省城市地下工程与环境安全重点实验室;建筑健康监测与灾害预防技术国家地方联合工程实验室;安徽省建筑科学研究设计院;
【基金】：中央高校基本科研业务费专项资金资助项目(2242014R30020) 江苏省高校“青蓝工程”优秀青年骨干教师培养对象资助项目(2014)~~
【分类号】：TU473.1

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