青藏冻结粉土与混凝土基础接触面本构关系研究

土冻结过程中,冰胶结作用使周围土体颗粒与建(构)筑物基础联成一体,这种胶结力称为土与基础间的冻结强度,通常采用冻土沿物体(例如基础材料)表面的剪切强度来度量。因而,冻土与基础接触面的应力-应变关系及其强度特征是确定冻土区基础工程承载力、抗拔性能和分析构筑物与冻土相互作用的基础和关键。为了更好地服务于工程实际,通过大量的冻结粉土与混凝土基础接触面剪切试验,总结了冻土接触面的基本力学特征和受力变形规律。根据获取的剪应力-位移曲线和冻结粉土接触面强度变化规律,利用标准本构模型建模方法,建立了冻结粉土接触面应力-位移-温度本构方程。该模型可以较好地描述不同温度冻结粉土接触面应力-位移变化规律,并为冻土区构筑物受力和变形数值计算提供基础。

Study of constitutive relation of interface between frozen Qinghai-Tibet silt and concrete

The ice cementation effects to the structure surface bond soil particles and infrastructure together during soil freezing. This cementing force is named freezing strength between frozen soil and foundation which is usually measured by means of the shearing strength of the interface. Hence, the strength characteristics as well as the relations between shearing stress and shearing strain of interface are very important to analyze the interaction between structures and the permafrost and to determine the uplift performance of foundation in permafrost regions. For better engineering application, a series of laboratory direct shear tests on the adfreezing interface between frozen soil and concrete plate are performed to investigate the mechanical behavior of the interface. Based on the stress and shear displacement relation of the interface and standard modeling method, a stress-displacement-temperature constitutive equation of the interface is deduced to describe the mechanical behaviors of the adfreezing interface. Experimental results indicate that the constitutive model can reasonably describe the stress-displacement principles for different temperatures. The constitutive relation can also be used in the numerical simulation of stress and deformation of the structures in cold regions.