School of Civil Engineering and Architecture, Anyang Normal University, Anyang, Henan, China.
CTG Operation and Administration Center for River Basin Hydro Complex, China Three Gorges Corporation, Yichang, Hubei, China.
PLoS One. 2023 Aug 15;18(8):e0290025. doi: 10.1371/journal.pone.0290025. eCollection 2023.
Under the different temperature environment, the precast pile-soil interface characteristics has an important impact on the safety and long-term stability for pile foundation. A large precast pile-soil shear experimental device is used to carry out the direct shear test of concrete-loess interface with different moisture contents under different freezing temperatures. The variation laws of shear strength parameters are revealed with influencing factors, and the shear mechanism of interface is discussed. The stress-strain constitutive equation of interface is proposed, and the shear strength criterion is established with considering the effects of temperature and moisture content on cohesion and internal friction angle. The results show the curve of shear stress and shear displacement can be divided into three stages: elastic deformation stage, plastic deformation stage and sliding failure stage, which macroscopically reflects the shear failure mechanism of the frozen soil-concrete interface. The shear strength of the interface is affected by the test temperature, sample moisture content and normal stress. The lower the test temperature, the greater the shear strength of the interface; With the increase of normal stress, the shear strength of interface increases; With the increase of moisture content, the shear strength of the interface increases and then decreases. The relationship of shear stress and shear displacement of frozen soil-concrete interface can be well described by the piecewise combination of hyperbolic function and linear function.
在不同的温度环境下，预制桩-土界面特性对桩基的安全性和长期稳定性有重要影响。采用大型预制桩-土直剪试验装置，对不同冻结温度下不同含水量的混凝土-黄土界面进行直接剪切试验。揭示了剪切强度参数的变化规律及其影响因素，探讨了界面的剪切机理。提出了界面的应力-应变本构方程，并建立了考虑温度和含水量对凝聚力和内摩擦角影响的剪切强度准则。结果表明，剪切应力与剪切位移曲线可分为弹性变形阶段、塑性变形阶段和滑动破坏阶段，宏观上反映了冻土地基-混凝土界面的剪切破坏机制。界面的抗剪强度受试验温度、试样含水量和法向应力的影响。试验温度越低，界面的抗剪强度越大；随着法向应力的增加，界面的抗剪强度增加；随着含水量的增加，界面的抗剪强度先增加后减小。冻土地基-混凝土界面的剪切应力与剪切位移关系可用双曲函数和线性函数的分段组合很好地描述。
