钻孔灌注桩桩侧泥皮分布对桩承载性状影响研究  

ANALYSIS ON DISTRIBUTION OF SIDE MUD INFLUENCE ON BEARING CAPACITY OF BORED PILE

作　　者：董志高 董平[2] 李俊才[3] 张志铖 

机构地区：[1]南京南大岩土工程技术有限公司,南京210024 [2]南京大学地球科学与工程学院,南京210008 [3]南京工业大学土木工程学院,南京210009

出　　处：《地质灾害与环境保护》2010年第4期94-99,共6页Journal of Geological Hazards and Environment Preservation

摘　　要：泥皮的存在会使灌注桩承载力降低,由于受施工工艺、方法以及现场条件影响,泥皮并不全部分布于整个桩壁四周,而是存在于部分区域。用折减桩土接触面参数的方法来模拟泥皮作用,对不同高度分布的泥皮进行数值方法模拟,分析不同泥皮分布高度对灌注桩的承载性状影响。计算结果表明,泥皮分布高度越高,荷载-沉降曲线越陡,拐点位置不断前移,当泥皮性状比α=0.8时,极限承载力损失约在5%-25%,当α=0.6时,极限承载力损失约在5%-50%。泥皮分布高度对桩侧摩阻力的影响与上部荷载作用下泥皮性质能够提供的极限摩阻力有关;有泥皮存在的部位,桩身轴力传递速率明显加快,泥皮分布高度越高,桩身轴力传递速率越快,且越向下部,泥皮分布高度对轴力的影响越大;泥皮分布越高,桩侧摩阻力就越容易达到极限摩阻力,导致泥皮分布越高,桩端阻力越大。Side mud of pile will reduce the capacity of pile.Due to the different construction technology,construction methods and site conditions,the side mud is not fully distributed around the whole pile,but in some regions.The method by reduction coefficient of pile-soil interface is used to analyze the distribution of different height side mud influence on bearing capacity of bored pile with finite element method.The results show that： The higher distribution of side mud,load-settlement curve of pile more steep.When the value α of the effect ratio of side mud equals to 0.8,the loss of the ultimate bearing capacity is about 5%～25%.When α=0.6,the loss of the ultimate bearing capacity is about 5%～50%.Height distribution of side mud influence on shaft resistance of pile was related to the ultimate frictional resistance of pile provided by side mud under different vertical load.Where there is side mud,the transmission rate of column load was significantly accelerated.The higher the side mud of pile,faster transfer rate of column load of pile.The higher of side mud,frictional resistance of pile easier to ultimate bearing capacity,so that,the greater the toe resistance of pile.

关 键 词：钻孔灌注桩 桩侧泥皮 分布高度 有限元法 承载性状 

分 类 号：TU473.14[建筑科学—结构工程]