摘要
基坑开挖后坑底土体回弹,将会带动坑内基桩回弹,并在桩侧产生侧摩阻力。为了分析基坑开挖条件下单桩及群桩的受力变形特性,采用三维有限元方法对单桩及群桩在基坑开挖条件下的回弹位移进行了分析。分析结果表明,基桩在基坑开挖条件下的回弹位移分为桩侧土体回弹而引起的基桩回弹和下卧层回弹导致的基桩回弹两部分。由于群桩外侧桩的遮帘效应,中心桩的回弹位移小于外侧桩,中心桩桩侧摩阻力的发挥量也小于外侧桩。随下卧层相对刚度Eb/Ec变大,5×5群桩回弹位移相对减小量Wr变大,且Wr的变化与桩位置有关。3种不同构形群桩的对比分析结果表明:群桩桩数越多,遮帘效应越明显;Wr受桩数的影响大于受桩间距的影响。
Pit soil rebounding during excavation will cause piles rebound and produce lateral friction in pit.Three-dimensional finite element analysis method was conducted to study the behavior of single pile and pile group under excavation.Results show that the rebounding displacement of single pile can be divided into two parts,namely,one is caused by the rebounding of soil around the pile and the other is caused by the rebounding of the bearing layer.The rebounding displacement and the degree of lateral friction of central pile were reduced by the shielding effects of outer piles.The relative reduction in rebounding displacement in 5×5pile group increased with the increase of relative bearing stiffness ratio, and this kind of variation depended on the pile location in the group.Based on three cases studied,thelarger the number of piles in a group,the greater the shielding effects presented.The number of piles had greater influence on shielding effect than pile spacing.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2014年第2期584-590,共7页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(40902077
41202197)
关键词
基坑开挖
回弹位移
单桩
群桩
excavation
rebounding displacement
single pile
pile group
