Experimental study on the mixed mode I-III fracture behaviors of sandstone after high temperature treatment

被引：0
作者：
Li W. [1 ]
Su H. [1 ]
Yu L. [1 ]
Liu R. [1 ]
Chen G. [2 ]
机构：
[1] State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Jiangsu, Xuzhou
[2] Shandong Energy Group Luxi Mining Co Ltd, Shandong, Heze
来源：
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | 2023年 / 40卷 / 06期
关键词：
fracture toughness; high temperature; mixed mode Ⅰ-III fracture; rock mechanics; tensile strength;
D O I：
10.13545/j.cnki.jmse.2023.0071
中图分类号：
学科分类号：
摘要：
The underground coal gasification and other projects involve significant high temperature thermal effect, which makes the strength, deformation and fracture characteristics of underground coal and rock become extremely complex. Based on the three-point bending loading method of disc with prefabricated fissure, mixed mode Ⅰ-III fracture properties of sandstone specimens after subjected to high temperatures (25-800 ℃) are studied, to investigate the influence of temperature on the effective fracture toughness, fracture energy and micro-structure. The results show that, the effective fracture toughness of sandstone presents a linear increase trend with the increasing fracture mixed coefficient Me13. The mode Ⅰ fracture toughness is the largest under the same condition, however, that of mode III is the smallest. With the gradual increase of temperature (in the range of 25-800 ℃), both the effective fracture toughness and fracture energy first increase slowly, and decrease sharply after 400 ℃, which is mainly related to the phase transformation of quartz. At 400 ℃, intergranular cracks are the main microscopic morphology of sandstone after high temperature treatment, while at 800 ℃, more transgranular cracks are formed due to the mineral phase transformation and decomposition. The mode III fracture toughness of sandstone generally obeys the linear law with that of mode Ⅰ, namely KIIIC = 0. 65KⅠC. Meanwhile, both the mode III and mode Ⅰ fracture toughness appear a great positive linear relationship with the tensile strength. © 2023 China University of Mining and Technology. All rights reserved.
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页码：1281 / 1289
页数：8
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