石灰岩和砂岩高温力学特性的试验研究

利用自行研制的岩石加温装置和RNT-150C岩石力学试验机，对石灰岩和砂岩试样高温后的力学特性进行了试验研究。试验结果表明，随着温度升高，两种岩石纵波波速逐渐减小。单轴压缩过程中的全程应力应变曲线经历了压密、弹性、屈服、破坏4个阶段；达到峰值应力后两种岩石均发生脆性破坏，砂岩破坏时呈锥形炸裂，而石灰岩则呈草捆状破坏。高温对两种岩石的强度都有一定的弱化作用，其峰值应力都随温度升高而降低，石灰岩700℃时强度降幅达84．59％，而砂岩强度仅比常温降低22％左右。两种岩石的峰值应变都随温度升高逐渐增大，但具体表现不尽相同，石灰岩500℃时应变增加了30．57％，500℃之后峰值应变基本无变化，甚至到700℃时还略有降低；砂岩700℃时峰值应变增加了80．63％，其峰值应变的变化与其微观结构变化相关。随着温度升高，两种岩石的弹性模量和变形模量均减小，700℃时石灰岩弹性模量降幅为86．8％，砂岩弹性模量降幅为46．94％；700℃时石灰岩变形模量下降了83．9％，砂岩的变形模量下降了53．06％。

EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF LIMESTONE AND SANDSTONE UNDER HIGH TEMPERATURE

The mechanical properties of limestone and sandstone under high temperature were investigated by the experiment device used to heat rock designed by ourselves and servo-control testing machine RMT-150C.The results show that the longitudinal wave velocity of two kinds of rocks gradually reduced with temperature increasing.The complete curve of stress and strain under uniaxial compression went through 4 stages,namely densification,elasticity,yielding and failure.They both displayed brittle fracture after reac...