湿陷性黄土地基大跨度桩基承载特性模型试验
Model test on bearing characteristics of long-span pile foundation of collapsible loess foundation
刘小华 1廖红建 2李明泽 3刘少华 3李杭州3
作者信息
- 1. 广州地铁设计研究院股份有限公司,广东广州 510010;西安交通大学城市学院土木建筑工程学院,陕西西安 710018;西安交通大学人居环境与建筑工程学院,陕西西安 710049
- 2. 西安交通大学城市学院土木建筑工程学院,陕西西安 710018;西安交通大学人居环境与建筑工程学院,陕西西安 710049
- 3. 西安交通大学人居环境与建筑工程学院,陕西西安 710049
- 折叠
摘要
城市车辆段上盖开发工程中的大跨度桩基具有单桩竖向承载较大、桩间大跨度范围内土体受荷较小的特点.以西安地铁某车辆段大跨度桩基为研究对象,制备人工湿陷性黄土作为相似材料,开展了湿陷性黄土地层大跨度桩基的室内模型试验,研究大跨度桩基在湿陷性黄土地层中的荷载传递机制与变形规律.结果表明:制备的人工湿陷性黄土与现场原状黄土性质接近,将其应用于模型试验时可以得到良好的效果;大跨度桩基在未浸水时,荷载沉降曲线为陡降型,桩身轴力在桩顶附近显著下降,未达到极限承载力时,桩顶沉降、桩端阻力线性增大;在黄土浸水湿陷后,桩身轴力沿埋深方向呈"D"字型分布,随着浸水时间的增加,桩顶沉降、桩端阻力先缓慢增加后显著增加,中性点位置不断向桩身下部移动.
Abstract
The long-span pile foundation in the development project of the superstructure of the urban depot has the characteristics of larger vertical bearing of a single pile,and the soil within the large span between the piles is lesser stressed.Taking the long-span pile foundation of a depot of Xi'an Metro as the research object,artificial collapsible loess is prepared as a similar material.An indoor model test of long-span pile foundation in collapsible loess layer was carried out.The load transfer mechanism and deformation law of long-span pile foundation in collapsible loess layer were studied.The results show that the prepared artificial collapsible loess is close in nature to the original loess on site,which can achieve good results in the application of model tests.When the long-span pile foundation is not flooded,the load-settlement curve is steep,and the axial force of the pile body decreases significantly near the top of the pile.When the ultimate bearing capacity is not reached,the pile top settles and the pile end resistance increases linearly.After the loess is flooded,the axial force of the pile body is distributed in a"D"shape along the direction of burial depth.With the increase of water immersion time,the pile top settlement and pile end resistance first slowly increased and then increased significantly,and the neutral point position continued to move to the lower part of the pile body.
关键词
湿陷性黄土/桩基/模型试验/负摩阻力Key words
collapsible loess/pile foundation/model testing/negative friction resistance引用本文复制引用
基金项目
国家自然科学基金(51879212)
国家自然科学基金(41630639)
陕西省重点研发计划项目(2019KWZ-09)
陕西省秦创原"科学家+工程师"队伍建设项目(2023KXJ-178)
出版年
2024
NETL
NSTL
万方数据