不同初始饱和度红砂岩冻融后物理力学性质研究

Study on physical and mechanical properties of red sandstone with different initial saturation after freeze-thaw

摘要:

对不同初始饱和度红砂岩冻融循环前后进行物理及力学试验研究，探讨初始饱和度对红砂岩冻融损伤的影响。本文设定红砂岩试样初始饱和度为20%、40%、60%、80%、100%，冻融次数设定为20次，对冻融前后试样分别测定质量、纵波波速以及进行单轴压缩试验。试验结果表明：（1）冻融后不同初始饱和度红砂岩的物理性质发生变化，纵波波速降低、质量损失率增大，但变化程度不同；（2）随饱和度的增大，试样经冻融后峰值强度和弹性模量均呈降低趋势，但只有饱和度＞60%时，降低趋势较明显；（3）随饱和度增大，试样冻融系数逐渐减小。本文研究为寒区边坡工程治理、地下工程建设以及岩土地质灾害监测与治理提供理论依据和试验基础。

关键词:红砂岩;初始饱和度;冻融循环;物理力学性质;冻融损伤;寒区边坡工程治理

Abstract:

The effects of initial saturation on freeze-thaw damage on red sandstone were studied by physical and mechanical experiments before and after freeze-thaw cycles. The initial saturation of the red sandstone samples was set as 20%， 40%， 60%， 80% and 100%， and the number of freeze-thaw cycles was set as 20. The mass and p-wave velocity were measured， and uniaxial compression tests were conducted of the sample before and after freeze-thaw respectively. The experimental results showed that： （1）After freeze-thaw， the physical properties of red sandstone with different initial saturation have changed with the p-wave velocity decreasing， and the mass loss rate increasing. （2）With the increase of saturation， the uniaxial compressive strength and elastic modulus of the sample tend to decrease after freeze-thaw， but only when the saturation is greater than 60%， the decreasing trend is more obvious. （3）With the increase of saturation， the freeze-thaw coefficient decreases gradually. The study can provide theoretical basis and experimental basis for construction of geotechnical works and monitoring and control of geo-hazards in the cold region.

Key words:red sandstone;initial saturation;freeze-thaw cycle;physical and mechanical properties;freeze-thaw damage;slope treatment at the cold region