摘要
利用自行研制的岩石加温装置和RMT-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%。
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-eontrol 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 reaching peak strength, with the sandstone rupturing and the limestone showing failure like a bundle of grass. The high temperature weakened their strength. Their peak stresses reduced with temperature increasing. At 700℃, the peak strength of limestone decreased by 84.59 %, while that of sandstone only decreased by 22 %. Their peak strain increased with temperature increasing, but differed in details. For limestone, its peak strain increased by 30.57 % at 500℃, but almost kept unchanged at the higher temperature, and even shaw a little decrease at 700℃. For sandstone, however, the peak strain increased by 80.63 % at 700℃ displaying a connection with the variation of microstructure. With temperature increasing, their elastic modulus and deformation modulus decreased. At 700℃, limestone decreased by 86.8 % in elastic modulus and by 83.9 % in deformation modulus, while sandstone decreased by 46.94% in elastic modulus and by 53.06 % in deformation modulus.
出处
《地质力学学报》
CSCD
2009年第3期253-261,共9页
Journal of Geomechanics
基金
国家自然科学基金资助项目(50274038
50574037)
关键词
石灰岩
砂岩
高温
纵波波速
力学性质
单向约束条件
limestone
sandstone
high temperature
longitudinal wave velocity
mechanical properties
