摘要
根据不同桩端条件下大直径灌注桩静载试验结果,研究桩端沉渣和预压对灌注桩承载性能的影响,并对沉渣的承载机理及桩侧摩阻力的弱化或强化效应进行探讨。结果表明:单桩极限承载力随桩端土层强度和刚度的增大而增大,桩端少量沉渣的压缩有利于侧摩阻力发挥到极限值,而无沉渣的完好桩端阻力和侧摩阻力一般难以发挥到极限值。此外,沉渣较厚或持力层强度较低时,侧摩阻力往往产生弱化效应,沉渣较少或持力层强度较高时侧摩阻力又往往产生强化效应,这种弱化或强化效应在桩端处最明显。沉渣具有结构性和压硬性的特性,在受压过程中因结构破坏而产生刚度弱化,经充分压实后又产生刚度强化,承载性能接近持力层。
Based on the results of the static load test under different pile tip conditions,influences of sediment and preloading on the bearing behavior of large-diameter cast-in-situ piles were researched. In addition, bearing mechanics of sediment and hardening or softening effect of skin friction of piles were studied. Results showed that ultimate bearing capacity of single pile increased with the strength and stiffness of pile-tip soils and smaller compression of pile-tip sediment was beneficial to develop skin friction to ultimate value,while the pile-tip resistance and skin friction of defect free pile without sediment were difficult to develop to the limit. Furthermore,the skin friction used to produce softening effect when the sediment was thick or the strength of the bearing stratum was low.And otherwise,the skin friction was often hardened,and the effect was most obvious at pile tip. Besides,the sediment had structure and compression hardening. Due to the structural failure in the process of compression,the stiffness of sediment weakened first,then strengthened by adequate compression and its bearing behavior approached the bearing stratum.
作者
熊玉春
XIONG Yuchun(Guangdong Construction Quality & Safety Testing Center,Guangzhou 510000,China)
出处
《工业建筑》
CSCD
北大核心
2019年第1期107-114,共8页
Industrial Construction
关键词
侧摩阻力
弱化效应
强化效应
沉渣
结构性
预压
skin friction
softening effect
hardening effect
sediment
structure
preloading
