超大直径钻孔灌注桩成桩过程的钢护筒受力分析  

Mechanical Analysis of Steel Casing Pipes of Large Diameter Cast-in-situ Bored Pile's Pile-forming Process

作　　者：李媛媛 俞瑾 曹平周[1] 

机构地区：[1]河海大学土木与交通学院,南京210098

出　　处：《三峡大学学报（自然科学版）》2018年第1期54-58,共5页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金"钢-混凝土组合结构粘结滑移统一理论及其破坏准则的研究"(50478044)

摘　　要：建在江河湖泊中的深水大跨越输电塔多采用大直径钻孔灌注桩基础,钢护筒是保证灌注桩成孔与成桩质量和安全的重要部件.结合苏通长江大跨越输电塔设计方案中的超大直径钻孔灌注桩工程,运用有限元分析软件ABAQUS,对超大直径钻孔灌注桩成桩过程进行数值模拟分析,研究江中超大直径钻孔灌注桩成桩过程中钢护筒的受力性能.研究表明,钢护筒应力随钻孔深度增加而增大,钢护筒内浇筑混凝土后随混凝土凝结和硬化而逐渐减小.成桩过程施工的最不利工况为钻孔完成后浇筑混凝土前阶段,此工况下钢护筒应力达到最大值,建议以此工况作为钢护筒结构设计的控制工况.钢护筒成桩后的施工应力最大值占钢材强度设计值的24.7%,建议结构设计若选用钢护筒参与桩身受力方案,应考虑施工应力.Large span transmission tower built in rivers and lakes in the deepwater usually use large diameter bored pile foundation; steel casing pipes are important components which ensure the quality and safety of pou- ring piles into the hole and into the piles. Combining one of Su-Tong Yangtze River large span transmission tower design- large diameter cast-in-situ bored pile construction, the finite element analysis software ABAQUS is used to carry out the numerical simulation analysis of the process of large diameter cast-in-situ bored piles into piles, and study the mechanical behavior of steel casing pipes of large diameter cast-in-situ bored pile＇s bored and pile process in the river. Study results show that： Steel casing pipes＇ stress increases with the drilling process and decreases with the concrete condensation and hardening after pouring concrete. The most unfavorable conditions of pile construction process is pre-pouring concrete stage after the comple- tion of the drilling phase; steel casing pipes＇ stress reaches a maximum in this condition. This condition is recommended as a control condition for steel casing pipes structure design. The maximum stress of construc- tion after steel protecting tube pile is 24.7% of the steel strength design value. This article suggests that if structural design using steel casing pipes in pile body stress solution, the construction stress should be considered.

关 键 词：钢护筒 ABAQUS 泥浆护壁 钻孔桩 受力性能 

分 类 号：TU473[建筑科学—结构工程]