冻结黏土力学性能多参数试验研究

Multi parameter experimental study on mechanical properties of frozen clay

为获得冻结黏土力学性能的相关参数及其变化规律,从皖北某矿获取三个层位的原状土样,通过冻胀试验、单轴抗压强度试验、抗剪强度试验和蠕变试验,获得了冻结黏土的弹性模量、泊松比、内摩擦角和黏聚力等物理参数及变化规律。试验结果表明:冻土的冻胀规律可用指数函数来描述,冻胀率、冻胀力都在经历最初的快速发展后,最终趋于稳定;在-15~-5℃范围内,各土层冻土的弹性模量、单轴抗压强度、黏聚力均随温度降低而增大,而泊松比随温度降低而减小;在应力水平较低条件下,冻土蠕变基本上属于稳定性蠕变;当应力水平较高时,试验结果属于非稳定性蠕变。

In order to obtain the mechanical properties of frozen clay and its change law,undisturbed soil samples of three layers were obtained from a mine in Northern Anhui Province.Through frost heave test,uniaxial compressive strength test,shear strength test and creep test,the physical parameters and change rules of elastic modulus,Poisson’s ratio,internal friction angle and cohesion of frozen clay were obtained.The experimental results show that:the frost heaving law of frozen soil can be described by exponential function,the frost heaving rate and frost heaving force tend to be stable after the initial rapid development;in the range of-15~-5℃,the elastic modulus,uniaxial compressive strength and cohesion of frozen soil in each soil layer increase with the decrease of temperature,while Poisson’s ratio decreases with the decrease of temperature.Under the condition of low stress level,the creep of frozen soil basically belongs to stable creep;when the stress level is high,the test result belongs to unstable creep.