基于微观机理的高温后大理岩动态力学特性分析
Analysis of the dynamic mechanical properties of marble after high-temperature exposure based on microscopic mechanisms
宋世兴1
作者信息
摘要
为研究温度对大理岩动态力学特性的影响,对常温(25℃)及高温(200℃、400℃、600℃和800℃)后的大理岩试样开展SHPB试验、XRD和SEM微观试验,探究了高温后大理岩动态力学特性与温度的关系及微观损伤机理.结果表明:高温后大理岩的动态压缩应力-应变曲线分为弹性、屈服、破坏3 个阶段;大理岩的峰值应力及破坏特征均存在明显的温度效应,即随温度的升高,大理岩的峰值应力逐渐下降,破碎程度加剧;大理岩的动态力学特性与其矿物组分及晶体结构密切相关,200℃～600℃时,微缺陷增多,且白云石发生了热分解转化,在800℃时,矿物分解生成CO2 气体和氢氧化钙,且晶体结构发生熔融破坏,内部损伤严重,塑性增强,从而导致宏观力学特性的大幅下降.
Abstract
To study the effect of temperature on the dynamic mechanical properties of marble,dynamic compres-sion tests,XRD,and SEM microscopic tests were conducted on marble samples at room temperature(25℃)and after exposure to high temperatures(200℃,400℃,600℃,and 800℃).The relationship between the dynamic mechani-cal properties of marble and temperature,as well as the microscopic damage mechanisms,were explored.The results show that the dynamic compressive stress-strain curves of marble after high-temperature exposure can be divided into 3 stages:elastic,yield,and failure.The peak stress and failure characteristics of marble exhibit a significant tempera-ture effect:as the temperature increases,the peak stress of marble gradually decreases,and the degree of fragmentation intensifies.The dynamic mechanical properties of marble are closely related to its mineral composition and crystal structure.Between 200℃and 600℃,micro-defects increase,and dolomite undergoes thermal decomposition and transformation.At 800℃,mineral decomposition produces CO2 gas and calcium hydroxide,and the crystal structure undergoes melting damage,leading to severe internal damage and increased plasticity,resulting in a substantial decline in macroscopic mechanical properties.
关键词
深部开采/大理岩/高温作用/微观损伤机理/动态力学特性/动态压缩试验Key words
deep mining/marble/high-temperature effect/microscopic damage mechanism/dynamic mechanical property/dynamic compression test引用本文复制引用
出版年
2024
NETL
NSTL
万方数据