Comparative experimental study on physical and mechanical properties of granite after natural cooling and under real-time high temperature

doi:10.13745/j.esf.2020.1.19

Abstract

Abstract:

The change of physical and mechanical properties of rock under high temperature has a direct impact on the development and utilization of hot dry rock resources and stability of underground reservoirs. Here, we studied granite through physical property and uniaxial compression testing with high temperature natural cooling and real-time temperature treatments. We analyzed and compared the physical and mechanical property changes of the specimens at different temperatures under the two treatments. The results are as follows: (1) The mass of granite decreased with increasing temperature by 0.24% and 0.27%, respectively, while the volume of granite increased with increasing temperature by 4.21% and 3.53%, respectively, under the two treatments. (2) The peak strength and elastic modulus of the specimens decreased as a whole; at 600 ℃, the peak strength decreased by 49.81% and 37.19%, respectively; elastic modulus decreased by about 34.35% and 26.13%, respectively; and the peak strain increased by 70.43% and 39.62%, respectively. (3) At below 400 ℃, mechanical properties of the specimens weakened less after natural cooling than under real-time temperature treatment, but the trend reversed at temperatures higher than 400 ℃, and a high temperature inflection point appeared. The research results can provide reference for stability evaluation of hot dry rock resources and real-time high temperature rock in practical engineering.

Key words: high temperature rock, natural cooling, real-time temperature, physical properties, mechanical properties

CLC Number:

LUO Shengyin, DOU Bin, TIAN Hong, CHEN Jie, XIAO Peng, ZHANG Shitao. Comparative experimental study on physical and mechanical properties of granite after natural cooling and under real-time high temperature[J]. Earth Science Frontiers, 2020, 27(1): 178-184.

Figures/Tables 10

Fig.1 Granite specimen

Table 1 Grouping of specimens

试样分组	温度/℃	试样数量
T₁	25	3
T₂	200	6
T₃	300	6
T₄	400	6
T₅	500	6
T₆	600	6

Fig.2 Relationship between mass loss rate and temperature

Fig.3 Relationship between volume increase rate and temperature

Fig.4 Relationship between density change rate and temperature

Fig.5 Relationship between p-wave velocity and temperature

Fig.6 The stress-strain curves of granites after natural cooling and under real-time temperature

Fig.7 Relationship between peak strength and temperature

Fig.8 Relationship between elastic modulus and temperature

Fig.9 Relationship between peak strain and temperature

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