关键词: 人工冻土, 单轴抗压强度, 冻结温度, 经验蠕变模型

Abstract: The artificial freezing method is not only commonly used in the excavation of subway side passages in soft soil,sand layers,and foundation pit support,but also in the construction of mine shafts with rich water,deep rock and soil.Mastering the physical,mechanical properties and creep laws of artificial frozen soil is essential for safe and fast construction.Perform uniaxial compressive strength tests at -5,-8,-10 and -15 ℃ and creep characteristics tests at different stress levels on the deep formation clay of a mine shaft constituted by the freezing method.The experimental results show that the compressive strength is linearly related to the freezing temperature;At the same test temperature,as the stress level increases,the axial deformation shows an upward trend;At the same stress level,as the test environment temperature decreases,the axial deformation shows a downward trend.Introduce an empirical creep model that takes into account the temperature effect,based on the linear relationship between the strain and time at each negative temperature and different stress levels,the linear expression is brought into the corresponding formula to solve the simultaneous equations to determine the model parameters.Comparing the calculated values of the model with the experimental data shows that the model can better simulate the initial deformation stage and the stable deformation stage of artificially frozen clay.The established model has the advantages of fewer parameters,easy determination,and clear physical meaning of the parameters,which provides an effective calculation method for the design of frozen walls.

Key words: artificial freezing soil,uniaxial compressive strength,freezing temperature,empirical creep model