摘要
由于膨胀土存在胀缩特性,膨胀土地基含水率改变导致的桩基承载力变化值得关注。基于三轴固结剪切试验,获得不同含水率条件下膨胀土的强度变化规律。建立膨胀土地基中单桩承载力三维弹塑性有限元分析模型,研究了地基含水率变化对桩基承载特性的影响,获得了极限承载力随地基土含水率的变化特性,并得出了桩身轴力、桩侧摩阻力分布规律。进一步分析表明,地基含水率升高导致桩的承载特性曲线由缓变型变为陡降型,在天然含水率附近极限承载力对地基含水率变化较敏感。对于不同含水率的地基,桩身轴力沿深度逐渐减小,桩侧摩阻力沿深度近似线性增加,在接近桩端处达到峰值之后急剧减小。地基含水率升高将导致桩侧阻力与桩端阻力之比明显增大,桩的类型由摩擦端承型向端承摩擦型转变。
Due to the swelling-shrinkage property of expansive soil,the variation of pile foundation bearing capacity caused by the change of moisture content of expansive soil foundation deserves attention.The strength characteristics of expansive soil with different moisture content were obtained through triaxial compression test A three-dimensional elasto-plastic finite element analysis model of pile foundation in expansive soil was established.The influence of soil moisture content on the bearing capacity of pile foundation was studied.The variation law of ultimate bearing capacity with soil moisture content was analyzed,and the distribution of pile axial force and pile lateral friction along the depth were obtained.Further analysis shows that the increase of foundation moisture content leads to the change of pile bearing characteristic curve from slow change type to steep drop type.For the pile foundation in expansive foundation with different moisture content,the axial force in pile decreases gradually along the depth,the pile side friction increases approximately linearly along the depth,and decreases sharply after reaching the peak near the pile end.The increase of moisture content in ground induces a significantly increase in the ratio of pile side friction to pile end resistance,and the pile wil change from end bearing type to end bearing friction one.
作者
吕玺琳
范琪
刘泳钢
江杰
Lü Xilin;FAN Qi;LIU Yonggang;JIANG Jie(Key Laboratory of Geotechnical and Underground Engin eering of Ministry of Education,Tongji University,Shanghai 200092,China;Department of Geotech nical Engineering,Tongji University,Shanghai 200092,China;Sichuan Institute of Building Research,Chengdu 610081,China;College of Civil Engineering,Guangxi University,Nanning 530004,China)
出处
《结构工程师》
2022年第3期117-122,共6页
Structural Engineers
基金
国家自然科学基金(52068004)
四川省科技厅项目(2021YFSY0037)。
关键词
膨胀土
含水率
桩
承载特性
数值模拟
expansive soil
moisture content
pile
bearing capacity
numerical simulation
作者简介
联系作者:吕玺琳(1981-),男,工学博士,教授,博士生导师,主要研究方向为岩土力学与工程。E-mail:xilinlu@tongji.edu.cn。
