武汉中心大厦超长软岩嵌岩桩承载特性试验研究

发布时间：2018-12-30 19:25

【摘要】：武汉中心大厦建筑总高度438 m,基底压力不小于1 000 k Pa,现场开展了桩径为1 000 mm、桩长64.0~68.0 m、以微风化泥岩为桩端持力层的4根嵌岩桩承载能力的静载试验,并对桩身轴力与变形进行了量测。试验结果表明:3根桩(试桩STZ1、STZ2、STZ2A)的荷载-沉降曲线为缓变型,1根桩(试桩STZ1A)受桩端沉渣影响,其荷载-沉降曲线为陡降型。最大荷载作用时各试桩的桩顶沉降25.14~33.7 mm,桩端沉降0.8~3.2 mm,桩身压缩量占桩顶沉降量90%以上,呈现超长桩特征。超长软岩嵌岩桩的侧摩阻力发挥特性与非嵌岩超长桩的侧摩阻力发挥特性有较大差异。4根试桩的端阻比介于19.8%~28.1%。软岩嵌岩桩实测桩端阻力高于岩石单轴抗压强度,采用JGJ 94—2008《建筑桩基技术规范》中的方法计算将低估其实际承载力。静载试验结果为本工程超长软岩嵌岩桩设计提供了依据,同时可为武汉地区超长软岩嵌岩桩实践与理论研究提供参考。
[Abstract]:The static load tests of four rock-socketed piles with a diameter of 1 000 mm, pile length of 64.0 ~ 68.0 m and bearing capacity of four rock-socketed piles with breezy mudstone as the bearing layer at the end of the pile were carried out in Wuhan Central Mansion with a total height of 438m and the base pressure not less than 1 000k Pa,. The axial force and deformation of the pile are measured. The test results show that the load-settlement curve of three piles (test pile STZ1,STZ2,STZ2A) is slowly modified, one pile (test pile STZ1A) is affected by sediment at the end of the pile, and the load-settlement curve is steeply reduced. Under the maximum load, the pile top settlement of each test pile is 25.14 ~ 33.7 mm, pile end settlement 0.8 ~ 3.2 mm, pile body compression amount accounts for more than 90% of the pile top settlement, showing the characteristics of super-long pile. The exertion characteristics of lateral friction of ultra-long soft rock socketed piles are quite different from those of non-embedded ultra-long piles, and the end resistance ratio of four test piles is between 19.880 and 28.1. The measured pile tip resistance of soft rock socketed pile is higher than that of rock uniaxial compressive strength. The actual bearing capacity will be underestimated by using the method of JGJ 94-2008 "Technical Specification for Building pile Foundation". The results of static load test provide a basis for the design of super-long soft rock socketed piles in this project, and also provide a reference for the practice and theoretical study of ultra-long soft rock socketed piles in Wuhan area.
【作者单位】：华东建筑设计研究院有限公司地下空间与工程设计研究院;
【基金】：“十二五”国家科技支撑计划(2012BAJ01B02) 国家自然科学基金项目(51508522)
【分类号】：TU473.16

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