摘要
基于已有试验和数值分析,针对倾斜荷载下能量桩的受力变形特性,通过优选桩-土材料参数、边界条件、分析步及网格类型等,实现了考虑热-力耦合作用的能量桩三维有限元模拟。进而通过与模型试验及二维数值所得桩顶沉降的对比分析,验证了三维有限元建模方法的合理性。最终通过改变竖向荷载、水平荷载及温差3个主要影响因素,探讨了桩顶沉降、桩侧摩阻力、水平位移及桩身弯矩变化规律,并提出相应的能量桩工程设计建议。研究表明,当温差ΔT>0℃时,桩体将产生热膨胀,甚至出现向上的位移,但其沉降-荷载曲线将随着竖向荷载的增大而逐渐趋近ΔT=0℃工况,桩侧摩阻力在桩身上、中部为负,在桩身下部为正,水平位移及桩身弯矩均大于ΔT=0℃工况;当ΔT<0℃时,桩身上、中部桩侧摩阻力为正,下部桩侧摩阻力为负,桩顶水平位移有所增大,但其原因不同于ΔT>0℃工况,桩身弯矩小于ΔT=0℃工况。
The three-dimensional finite element simulation for energy piles with thermo-mechanical coupling effects is implemented by optimizing the pile-soil material parameters,boundary conditions,steps and grid types,etc.In this analysis,the stress and deformation characteristics of energy piles under inclined loads are investigated based on the existing experimental and numerical results.Further,the modelling method is validated by comparing the settlements at pile head from this study and those from the model tests and two-dimensional numerical simulations.Finally,the laws of settlements at pile head,frictions at pile side,lateral displacements and bending moments are explored through the variation of three main influence factors:vertical loads,lateral loads and temperature differences,and the corresponding suggestions for engineering design of energy piles are proposed.The results show that when the temperature differenceΔT>0℃,the thermal expansion will appear and the vertical displacement atop the pile is even upward.However,with the increase of vertical loads,the settlement-load curves will gradually tend to the curve whenΔT=0℃.Besides,the frictions at pile side are negative on the upper and middle parts of piles,and are positive on the lower part of piles.The lateral displacements and bending moments whenΔT>0℃are both greater than those whenΔT=0℃.WhenΔT<0℃,the frictions at pile side are positive on the upper and middle parts of piles,and are negative on the lower part of piles.The lateral displacements at top of the pile whenΔT>0℃are greater than those whenΔT=0℃,the reason is different from that whenΔT>0℃,and the bending moments are less than those whenΔT=0℃.
作者
龚建清
彭文哲
GONG Jian-qing;PENG Wen-zhe(College of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2021年第11期2105-2111,共7页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51978255)。
关键词
能量桩
有限元分析
倾斜荷载
受力变形特性
约束条件
energy pile
finite element analysis
inclined load
deformation characteristic
constraint condition
