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A mesostructure-based damage model for thermal cracking analysis and application in granite at elevated temperatures

Citation

Yu, QL and Ranjith, PG and Liu, HY and Yang, TH and Tang, SB and Tang, CA and Yang, SQ, A mesostructure-based damage model for thermal cracking analysis and application in granite at elevated temperatures, Rock Mechanics and Rock Engineering, (online 24 December) pp. 1-20. ISSN 0723-2632 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 Springer

DOI: doi:10.1007/s00603-014-0679-5

Abstract

Thermal stress within rock subjected to thermal load is induced due to the different expansion rates of mineral grains, resulting in the initiation of new inter-granular cracking and failure at elevated temperatures. The heterogeneity resulting from each constituent of rock should be taken into account in the study of rock thermal cracking, which may aid the better understanding of the thermal cracking mechanisms in rock. In this paper, a mesostructure-based numerical model for the analysis of rock thermal cracking is proposed on the basis of elastic damage mechanics and thermal–elastic theory. In the proposed model, digital image processing (DIP) techniques are employed to characterize the morphology of the minerals in the actual rock structure to build a numerical specimen for the rock. In addition, the damage accumulation induced by thermal (T) and mechanical (M) loads is considered to modify the elastic modulus, strength and thermal properties of individual elements with the intensity of damage. The proposed model is implemented in the well-established rock failure process analysis (RFPA) code, and a DIP-based RFPA for the analysis of thermally induced stress and cracking of rock (abbreviated as RFPA-DTM) is developed. The model is then validated by comparing the simulated results with the well-known analytical solutions. Finally, taking an image from a granite specimen as an example, the proposed model is used to study the thermal cracking process of the granite at elevated temperatures and the effects of temperature on the physical–mechanical behaviors of the granite are discussed. It is found that thermal cracks mostly initiate at the location of mineral grain boundaries and propagate along them to form locally closed polygons at the elevated temperatures. Moreover, the effects of temperature on the uniaxial compressive strength and elastic modulus of the granite are quite different. The uniaxial compressive strength decreases consistently with increasing temperature, but there exists a threshold temperature for elastic modulus which starts to decrease as the temperature increases after it exceeds the threshold.

Item Details

Item Type:Refereed Article
Keywords:digital image processing, mesostructure-based damage model, thermal cracking, granite
Research Division:Engineering
Research Group:Resources Engineering and Extractive Metallurgy
Research Field:Geomechanics and Resources Geotechnical Engineering
Objective Division:Construction
Objective Group:Construction Processes
Objective Field:Civil Construction Processes
Author:Liu, HY (Dr Hong Liu)
ID Code:97702
Year Published:2014
Deposited By:Engineering
Deposited On:2015-01-09
Last Modified:2015-03-23
Downloads:0

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