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。
In order to investigate the load transfer mechanisms and bearing behavior of soil displacement screw（SDS） pile, a field full-scale test was carried out by BOTDA-based optical fiber sensing technique through embedding optical fiber in piles to detect the pile strain distribution under loading. Then the axial force, the side friction and the tip resistance of SDS pile were also analyzed. The bearing behavior of SDS pile was also compared with that of continuous flight auger（CFA） pile constructed in the same test field. The results indicate that distributed optical fiber monitoring can conveniently obtain load transfer mechanisms of piles. The tip resistance of SDS pile is smaller than that of CFA pile under the same load applied on the pile top, and the tip resistance of SDS pile accounts for about 8% of the whole load when reaching the ultimate bearing capacity, which implies that SDS pile can be considered as friction pile or end bearing friction pile in the design. The ultimate bearing capacity of SDS pile can be increased by 67% compared with that of CFA pile with the same pile parameters and soil conditions. The positive soil compacting effect induced by drilling construction leads to the increase of stress level, which promotes the side friction and therefore improves the bearing capacity of SDS pile.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2017年第3期779-786,共8页
Journal of Central South University:Science and Technology
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)~~
