摘要
高温岩石力学特性是煤炭地下气化等岩石工程围岩稳定分析和支护设计的重要依据。为揭示高温后岩石断裂特性,对两组不同孔隙率砂岩进行高温(25~800℃)处理,采用图像处理技术获得砂岩热裂纹分布特征,探究高温后砂岩微裂纹面积比演化规律;对高温后砂岩进行三点弯曲试验,分析高温对砂岩载荷-位移曲线、Ⅰ型断裂韧度及破裂模式的影响规律。结果表明:高温后砂岩微裂纹面积比随温度升高呈先减小后增大趋势,较高孔隙率C组砂岩微裂纹面积比更大;相同温度条件下,A组砂岩Ⅰ型断裂韧度高于C组砂岩;随着温度的升高,两组砂岩Ⅰ型断裂韧度均先增大后减小,阈值温度分别为200℃和400℃;三点弯曲作用下,从预制裂隙尖端萌生的裂纹扩展导致砂岩试样破坏,且温度越高,砂岩破坏程度越明显。
The mechanical properties of hot rock are important basis for rock stability analysis and support design of deep rock projects such as underground gasification of coal.In order to reveal the evolution of fracture behavior of rock after high temperature,a series of tests on sandstone specimens with two porosities after different high temperatures(25-800℃)were carried out.Digital image processing techniques were used to analyze the distribution characteristics of thermal cracking,and calculate the microcrack area ratio.Threepoint bending tests were performed on semicircular bend sandstone specimens after high temperature treatment.Based on the test results,the effects of high temperature on loaddisplacement curves,modeⅠfracture toughness and failure modes of sandstone specimens were analyzed.The results show that:the microcrack area ratio tends to decrease first and then increase with increasing temperature,and the microcrack area ratio of Group C sandstone with higher porosity is higher than that of Group A sandstone with lower porosity.The modeⅠfracture toughness of Group A sandstone is higher than that of Group C sandstone under the same testing temperature.As the temperature increases,the modeⅠfracture toughness of sandstone specimens first increase and then decrease.The threshold temperatures of the two groups of sandstones are 200℃and 400℃,respectively.The crack initiated from the prefabricated notch tip under threepoint bending leads to the failure of sandstone specimens.The higher the temperature,the more obvious the degree of fracture of the sandstone specimens.
作者
黄彦华
陶然
韩媛媛
陈笑
罗一鸣
武世岩
HUANG Yanhua;TAO Ran;HAN Yuanyuan;CHEN Xiao;LUO Yiming;WU Shiyan(School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Electrical Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2024年第2期430-436,共7页
Journal of Mining & Safety Engineering
基金
国家自然科学基金项目(51909260)
江苏省自然科学基金项目(BK20221547)
国家级大学生创新创业训练计划项目(202110290017Z)。
关键词
岩石力学
高温作用
Ⅰ型断裂韧度
微观结构
图像处理
rock mechanics
high temperature treatment
modeⅠfracture toughness
microstructure
image processing
