摘要
微型钢管桩具有承载力高、抗弯刚度大、施工速度快、地层适应性强等优点,广泛应用于基坑支护中。基于青岛某重点工程的基坑项目,采用水泥土桩内置微型钢管桩并结合预应力锚杆支护形式,通过对3根注浆微型钢管桩的现场桩身应力测试和室内抗弯试验,探讨基坑开挖过程中微型钢管桩的内力变化规律和承载机理。研究结果表明：微型钢管桩的最大弯矩发生在桩顶,桩身弯矩随着基坑开挖逐渐增大,沿深度呈上大下小的趋势,桩身弯矩的分布形态表明采用桩锚支护模式对微型钢管桩设计计算是合理的。通过对基坑位移的监测,得出了基坑位移随开挖深度的变化规律,说明注浆后的微型钢管桩植入到水泥土桩中,能够显著提高水泥土桩的抗弯刚度,达到限制基坑变形的目的。
Micro-steel pipe pile has been widely used in deep foundation excavation supporting because of its high bearing capacity,high flexural rigidity,fast constructed speed and strong adaptability for stratum. Based on a foundation excavation project in Qingdao,a new supporting form of combining the micro-steel pipe piles embedded in cement-soil piles with prestressed anchor supporting method was proposed. The inner force change laws and bearing capacity mechanism of micro-steel pipe pile were discussed by conducting in-situ stress measurement and laboratoy bending tests on three microsteel pipe piles. The results showed that the maximum bending moment occurred at pile head,and the bending moment of the pile gradually increased with the process of foundation excavation. It presented that the bending moment was larger at the upper and small at the lower along excavating depth,which showed that it was reasonable to design and calculate the micro-steel pipe pile by pile-anchor model. Through the monitoring of the displacement for the foundation,the variation law of the displacement of the foundation slope with the excavated depth was obtained. It was indicated that the grouted micro-steel pipe piles could be implanted in cement-soil pile,which could improve the flexural rigidity of cement-soil piles and limit the deformation of slope.
出处
《工业建筑》
CSCD
北大核心
2018年第2期134-138,168,共6页
Industrial Construction
基金
国家自然科学基金项目(51708316,51778312)
山东省重点研发计划(2017GSF16107)
山东省自然科学基金青年基金项目(ZR2016EEQ08,ZR2017PEE006)
山东省高等学校科技计划项目(J16LG02)
青岛市应用基础研究计划项目(16-5-1-39-jch)
关键词
微型钢管桩
水泥土桩
基坑
现场测试
室内试验
micro-steel pipe pile
soil-cement pile
foundation excavation
field test
laboratory test
