摘要
通过有限元计算,研究了大面积深基坑开挖对群桩的受力和变形特性的影响。群桩基础的受力及变形性状明显不同于单桩。对于坑底群桩,随着基坑开挖深度增加,桩身轴力随之增加,桩身轴力最大值位置由桩身中上部转移到中部,与单桩的轴力最大值位置(桩身中下部)有一定程度的差别。在同一开挖深度中,距离地下连续墙近的桩身轴力较小,距离基坑中心近的桩身轴力较大。其主要原因是基坑中心处的土体回弹大于基坑边部,相应的桩土位移及桩侧摩阻力发挥程度也较大。由于基坑开挖造成支护结构发生侧向变形,使得靠近支护结构的桩产生弯曲,整体表现为桩身上部变形较大,中下部变形较小。
The large deep excavation of the stress and strain in pile groups was analyzed with three dimensional finite elements analyses.The stress strain characteristics in the pile group are significantly different from those of in the single pile.For pile groups under the bottom of the excavation,the axial stress in the pile increases in the depth of the excavation.The location of the maximum force in the pile changes from the top to the middle part of the pile.Whereas,in the single pile（without pile cap）,the maximum axial force is located at the lower portion of the pile.At the same excavation depth,the smaller axial force could be found in piles near the slurry wall;large axial force can be found in piles that are close to the center of the excavation with a larger pile deformation and mobilized side resistance in piles.Due to the lateral deformation of the supporting structures,piles that are closed to the supporting structures have large bending moments.As a result,these piles have large deformation in the upper portion of the pile.
出处
《土工基础》
2016年第4期476-480,共5页
Soil Engineering and Foundation
关键词
基坑开挖
群桩
有限元
Deep Excavations
Pile Groups
Finite Element Methods
