抗拔桩承载特性研究与三维数值仿真分析  

CHARACTERISTICS AND 3D NUMERICAL SIMULATION ANALYSIS OF UPLIFT PILE BEARING CAPACITY IN URBANS

作　　者：熊昊[1] 刘润[1] 徐余[2] 

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072 [2]天津市建筑设计院,天津300074

出　　处：《工程地质学报》2013年第3期400-407,共8页Journal of Engineering Geology

基　　金：教育部新世纪优秀人才支持计划(NCET-11-0370);天津市自然基金面上项目(12JCYBJC14700)

摘　　要：随着城市建设的发展,地铁、地下停车场、地下商场等地下建筑更加普遍,且呈现多样化、复杂化、深入化的发展趋势,使得地下结构物的抗浮稳定性逐渐突显,其中设置抗拔桩是结构抗浮的主要工程措施之一。本文分析了抗拔单桩与群桩的地基破坏模式并揭示抗拔桩的工作机理,应用ABAQUS大型有限元软件对抗拔单桩模型以及群桩模型分别进行了数值模拟,从桩身应力、桩周土体、桩侧阻力等多个角度分析抗拔承载力的影响因素以及群桩效应,结合工程实例分析抗拔群桩距径比(λ)对抗拔承载力及地基变形的影响。结果表明:在上拔力作用下,单桩中的应力集中于轴心,沿半径及深度递减,桩侧摩阻力自上而下逐渐减小,但随着向上位移的增大而增大;当基桩的距径比λ减小时,承载力折减系数ξ增大,群桩效应显著,桩间土与桩有整体被拔起的趋势,不利于结构的抗浮稳定性;λ=3和λ=6可以作为划分群桩效应程度的界限。With the development of urban construction, underground structures including subways, underground parks and underground markets have become more and more widespread. Their development trends are diversified, complicated and deep-going. It can be known that anti-floating stability of underground structures become an out- standing problem. So, one of main project measures is to set up uplift piles. This paper mainly analyzes the ground failure mode of uplift pile and pile group, and reveals the work mechanism of uplift pile. The mode of uplift pile and pile group is numerically simulated using ABAQUS finite element： software. The influence factors of uplift ca- pacity and pile group effect are investigated in different aspects such as pile stress, soil around pile and pile side re- sistance. It further studies the effect of the distance-diameter ratio of uplift pile group on uplift capacity and founda- tion deformation combined with practical works. The analyzing results show that, under the action of uplift force, pile stress mainly acts in axis, which decreases with increasing radius and depth. The pile side friction force de- creases gradually from upper depth to lower depth. It increases with increasing upward displacement. When the distance-diameter ratio（ λ ） of foundation pile decreases, the capacity reduction factor（f） increases, the pile group effect is more significant, and there is an uplift trend in piles and soil between piles that go against the anti-floating stabili＇ty of construction. λ = 3 and h = 6 can be used as the limit ti determine the degree of pile group.

关 键 词：抗拔桩 破坏模式 数值分析 距径比 

分 类 号：TU473.1[建筑科学—结构工程]