摘要
根据钙质砂中桩基工程的现状,针对取自南沙群岛永暑礁的钙质砂,设计一个室内模型试验装置来研究钙质砂中钢管桩的承载和变形性能以及影响因素,并进行了石英砂中的对比试验。试验结果表明,钢管桩在钙质砂和石英砂中的表现有着显著差异。钙质砂中钢管桩承载能力很低,仅为石英砂的66%～70%,钙质砂中桩身轴力衰减速率缓慢,桩侧摩阻力远远小于石英砂的,仅为石英砂的20%～27%,并具有深度效应,开口钢管桩和闭口钢管桩的桩侧摩阻力相差不大。同时表明,钙质砂中桩侧摩阻力对相对密度的变化没有石英砂敏感,受相对密度影响很小。由颗粒破碎引起的桩周水平有效应力的大幅降低是造成钙质砂中钢管桩桩侧摩阻力低的主要原因。
According to the current situation of pile foundation engineering, a model test equipment is designed to study the bearing and deformation characteristics of steel pipe piles in calcareous sands, which are taken from Yongshu reef in Nansha Islands in South China Sea. In contrast to the tests with silica sands, it is shown that calcareous sands behave in a completely different manner than silica sands. For sands having the same relative density, the ultimate bearing capacity in calcareous sands is only 66-70% of that in silica sands, the axial force has a slow decay rate, and the ultimate shaft friction of open-ended piles is less than that of close-ended piles in calcareous sands, nonetheless, it is only 20-27% of that in silica sands. In addition, shaft friction is very sensitive to density in silica sands but less so in calcareous sands. It is found that the reduction in lateral pressures on the pile shaft, which is caused by grain crushing under the high stress levels produced during pile driving, is the main reason for low shaft friction of steel pipe piles in calcareous sands.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2010年第3期780-784,共5页
Rock and Soil Mechanics
基金
国家科技支撑计划重点项目(No2006BAB19B03)
国家自然科学基金重点项目(No50639010)
中国科学院武汉岩土力学研究所知识创新工程领域前沿项目(NoO712041Q01)
关键词
钙质砂
模型试验:钢管桩
桩侧摩阻力
颗粒破碎
calcareous sands
model test
steel pipe pile
shaft friction
grain crushing
