大直径超长桩总侧阻力与端阻力承载特性的比较  

COMPARISON OF THE BEARING CHARACTERISTICS OF TIP RESISTANCE AND SHAFT RESISTANCE FOR LARGE DIAMETER AND SUPER-LONG PILE

作　　者：蒋建平[1] 蔡赛男[1] 

机构地区：[1]上海海事大学海洋科学与工程学院,上海201306

出　　处：《工业建筑》2017年第6期95-101,共7页Industrial Construction

基　　金：国家自然科学基金面上项目(41372319)

摘　　要：通过对16个场地中共36根桩的现场试验资料的分析,对比研究大直径超长桩桩身总侧阻力与端阻力的承载性状,研究发现:桩身总侧阻力、端阻力在初始阶段是异步发挥的,侧阻力先发挥,然后两者就开始同步发挥,同步发挥是主要过程,两者发挥的差异主要表现在时间、增幅、绝对值大小等方面。与端阻力一样,桩身总侧阻力达到极限状态时的桩顶沉降值没有确定值,与Vesic认为的以桩顶沉降10 mm来确定有区别,说明桩身总侧阻力达到极限状态时的桩顶沉降值受土的类型、桩的几何尺寸、施工方法等因素综合影响;侧阻力达到极限状态的12根桩中有4根桩的侧阻力存在软化现象,而端阻力一般没有软化现象;桩端岩土强度的提高,不仅可大幅度提高端阻力,同时也可大幅度提高桩身总侧阻力。Based on the field testing data of 36 piles in 16 sites,the bearing characteristics of shaft resistance and tip resistance for large diameter and super-long pile were studied. It was found that in the initial stage,the shaft resistance and tip resistance were played out of sync,the shaft resistance played first,then the tip resistance played.But their interaction was main process. The difference of development reflected in precedence,amplitude and absolute value,etc. As tip resistance,the ultimate shafe resistance had no certain value related to pile top settlement,different from 10 mm settlement of pile top by Vesic,the pile top settlement was affected by types of soil,pile geometry dimension and construction methods; 4 piles＇ shafe resistance appeared to stress softening in 12 piles whose shaft resistance arrived at ultimate state; the improvement of pile tip soil and rock could greatly strengthen not only pile tip resistance but also pile shaft resistance.

关 键 词：桩侧阻力 桩端阻力 桩顶沉降 现场试验 大直径超长桩 发挥性状 

分 类 号：TU473.1[建筑科学—结构工程]