摘要
"武汉中心"大厦是目前华中在建的第一高楼,建筑高度438 m,88层地上结构,4层地下室,基础埋深约20 m。场地浅部为深厚的砂层,其下为软质泥岩。由于建筑高,预估单桩承载力极限值不小于20000 kN,当地无类似工程经验,桩基设计施工难度大。该工程开展了现场足尺试验,试桩桩径1000 mm,采用桩端桩侧联合后注浆提高承载力,桩端埋深约65 m。通过不同入岩深度进行对比,开展大吨位载荷试验、桩身轴力与变形的量测,得到嵌岩灌注桩的承载与变形状态;基于地基-基础-结构协同作用的理念对工程桩的受力作深入分析,得到合理的群桩布置与入岩深度;采用旋挖机具并配合针对性挖斗、泥浆与清渣工艺,解决了深厚砂层及软岩的成孔难题,大大提高工效并保证质量。
Wuhan Center Building,the highest building under construction in Central China,is 438 meters high with structure of 88 ground layers and 4 underground layers and an embedded foundation depth of 20 meters.Mild mud rock lies 60 meters below the basement.Pile foundation design is difficult because the estimated bearing capacity of a single pile is not less than 2000 kN due to the high structure and no available engineering experience.Post grouting into the end and side of test piles with a diameter of 1000 millimeters and a length of about 65 meters is applied to field full scale tests in order to compare situations of various rock insertion depths.Large tonnage load tests and measurements of axial force and deformation are carried out so that the status of load bearing and deformation capacity of socketed piles is obtained and the basis for pile foundation design is provided.Based on the idea of effect of ground,foundation and structure synergistic,rational layout of pile groups and rock insertion depth are obtained.In accordance with comparison and selection of different construction equipments and technologies,the rotary drilling machine,special bucket mud and slag cleaning technology are adopted.This can resolve pore-creating challenge for deep sand and mild rock layers and enormously enhance work efficiency and guarantee quality.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2013年第S1期76-81,共6页
Chinese Journal of Geotechnical Engineering
基金
十二五国家科技支撑计划课题(2012BAJ01B02)
关键词
嵌岩桩
现场试验
承载特性
旋挖
socketed pile
field test
bearing behavior
rotary drilling