武汉中心大厦超长软岩嵌岩桩承载特性试验研究  

Field loading tests on large-diameter super-long rock-socketed bored piles of the Wuhan Center Tower

作　　者：王卫东[1] 吴江斌[1] 聂书博 

机构地区：[1]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,上海200002

出　　处：《建筑结构学报》2016年第6期196-203,共8页Journal of Building Structures

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)

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。Wuhan Center Tower is 438 m high with the average pressure of 1 000 kPa on the bottom of foundation. Test piles with a diameter of 1 000 mm and a length of about 64. 0-68.0 m were applied to field full scale test. A series of pile load tests have been carried out on four bored piles socketed in slightly decomposed mud rock. Both axial load and displacements of the pile were monitored in the course of the test. The results show that the load-deformation curves of the piles STZ1, STZ2 and STZ2A are gradual and the load-deformation curve of the pile STZ1A is sharply dropping form due to pile-end sediment. The pile top settlements are 25.14-33.7 ram. The pile tip settlements are 0. 8- 3.2 ram. Pile compression occupies more than 90% of pile top settlement, showing the characteristics of super long pile. Side friction distribution and bearing characteristics of super-long rock-socketed piles are different from those of super-long non-rock-socketed piles. The tip resistance ratio of four piles are 19.8%-28. 1%. The measured base resistance of the socketed pile is larger than the uniaxial compressive strength of the soft rock. The bearing capacity of the pile predicted using the equation recommend in the ＇ Technical code for building pile foundation＇ （ JGJ 94-2008 ） is underestimated. The results of the field pile load tests provide bases for the design of super-long soft rock socked piles in the project. The tests also yield valuable data for practical application and theoretic investigation of super-long soft socketed piles in Wuhan.

关 键 词：超长软岩嵌岩桩 静载试验 承载性状 侧摩阻力 端阻力 

分 类 号：TU473.16[建筑科学—结构工程]