超长灌注桩对桩周土挤密作用的模型试验研究  

Model experimental research on compacting effect of concreting for overlength and large-diameter bored pile

作　　者：陈志坚[1] 刘艳军[1] 

机构地区：[1]河海大学土木工程学院,南京210098

出　　处：《岩土力学》2008年第12期3277-3281,共5页Rock and Soil Mechanics

基　　金：国家"十一.五"科技支撑资助项目(No.2006BAG04B05);国家重点基础研究发展规划(973)项目资助课题(No.2002CB412707)

摘　　要：对于呈密集布置的超长大直径钻孔灌注桩(尤其是高桩),凝固过程中的桩身混凝土对桩周土具有强烈的挤密作用,这对提高桩基础的整体性和承载性能、控制桩基础的沉降具有重要意义。针对苏通大桥主桥超大型群桩基础,在阐述模型试验的目的、方案以及监测点的布置的基础上,给出了桩侧挤密压力的分布和变化规律。试验结果表明,在桩身混凝土浇注后,其侧向挤密压力仍持续增大,尤其是初凝前,呈流塑状态的混凝土的侧压力增幅达8.4%～13.5%。在初凝后至14d,侧压力增幅仍可达0.8%。For over-length and large-diameter bored piles with dense distribution, especially for high-pile group, in the solidification process pile concrete brings intensive compacting effect on soil around the pile. It is significant for enhancing integrity and bearing capacity of pile group, and controlling settlement of the foundation. The purpose and scheme of the test are designed according to the super-large pile group foundation of Sutong Bridge. The test gives the distribution and change laws of lateral compacting pressure. It is shown that the lateral compacting pressure increases continuously after pouring the pile, especially for the concrete in flow-plastic before initial set, the increase amplitude is 8.4 to 13.5 percent. The lateral pressure still keeps 0.8 percent of increase from initial set to the 14th day of the test.

关 键 词：大直径 钻孔灌注桩 高桩 模型试验 挤密作用 苏通大桥 

分 类 号：TU473[建筑科学—结构工程]