冻融循环作用下砂砾岩微观结构损伤机制研究

Study on damage mechanism of glutenite microstructure under freeze-thaw cycles

以砂砾岩为研究对象,进行开放条件下变温度区间冻融循环试验,利用统计学原理和avizo软件重建三维模型。研究结果表明:岩石冻融劣化的主要原因是未冻水迁移、积聚,水分结晶膨胀导致岩石孔隙扩展、联通;将冻胀均化应力与岩石屈服强度对比,可判断岩石是否发生不可逆变形,便于进行岩石冻融损伤评价;提出温度区间是影响冻融损伤的关键性因素,饱和度为重要影响因素,岩石结构特征为次要影响因素,研究结果可为寒区岩土工程以控制环境温度、湿度及监测岩体结构特征为手段进行建设维护提供理论依据。

The freeze-thaw cycle test in variable temperature range under open conditions is carried out on glutenite samples,and the three-dimensional model is constructed using statistical principle and avizo software.The results show that the main causes of rock freeze-thaw deterioration are the migration and accumulation of unfrozen water,and the expansion of rock pores caused by water crystallization and expansion;comparing the frost heaving homogenization stress and rock yield strength can judge whether the rock has irreversible deformation,which is convenient to evaluate the rock freeze-thaw damage;the temperature range is the key factor affecting freeze-thaw damage,the saturation is the important factor and the rock structure characteristics are the secondary factors.The study provides a theoretical basis for the construction and maintenance of geotechnical engineering in cold area by controlling the ambient temperature,humidity and monitoring the rock mass structure characteristics.