不同低温温度下砂土物理力学特性试验研究

Experimental Study on the Physical Mechanics Characteristics of Sand Under Different Frozen Temperatures

以白垩系富水砂层砂土为研究对象,对其在不同低温温度下的物理力学特性进行了分析。结果表明:砂土比热容随冻结温度降低呈现出先减小后增大再减小最终趋于稳定的变化规律,砂土导热系数随冻结温度降低而逐渐增大最终趋于稳定,其变化过程主要分为3个阶段,即:缓慢增大阶段、迅速增大阶段和基本稳定阶段;随冻结温度降低人工冻结砂土粘聚力、内摩擦角、弹性模量和单轴抗压强度会逐渐增大,但增大的幅度会随着冻结温度的降低而逐渐减小;在同一加载速率下,不同冻结温度下人工冻结砂土变形均表现为应变软化,人工冻结砂土试样破坏时应变较小,一般介于6%~10%之间。

This paper takes the sand of Cretaceous water-rich stratum as the research object,and its thermodynamic characteristics at different low temperatures were analyzed.The results showed that:as the freezing temperature decreases,the specific heat capacity of sandy decreases first,then increases,then decreases,and finally becomes stable.The thermal conductivity of sand gradually increases with the decrease of freezing temperature and finally becomes stable,and its process of change can be divided into three stages:slow increase stage,rapid increase stage and basic stability stage.As the freezing temperature decreases,the cohesion,internal friction angle,elastic modulus and uniaxial compressive strength of the artificially frozen sand will gradually increase.However,the amplitude of the increase will gradually decrease as the freezing temperature decreases.At the same loading rate,the deformation of artificially frozen sand at different freezing temperatures is shown as strain softening and the strain is small when the artificially frozen sand sample damaged,which is generally between 6%and 10%.