升温和降温对无约束花岗岩热破裂的影响
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摘要
温度变化会引起岩石内部矿物颗粒膨胀(收缩)不均匀,发生热破裂。温度变化有温度升高和降低两种作用方式,本文通过无约束花岗岩在升温和降温两种温度作用方式下的热破裂声发射实验研究,得到如下结论:(1)花岗岩升温过程中热破裂主要表现为中高温弹塑性破裂;降温过程中热破裂主要表现为中低温脆性破裂;(2)升、降温过程岩石的热破裂机理不同,升温过程主要为压缩热应力集中形成的压剪破裂,降温过程主要为局部拉应力集中造成的拉剪破坏;(3)根据声发射特征参数统计分析,同等温度范围内,岩石降温过程的热破裂声发射事件频度和强度均高于升温过程,约为2倍,降温过程的热破裂比升温过程剧烈。
Temperature variation can cause uneven expansion( contraction) of mineral particles and result in thermal cracking in the rock. Temperature mode exposed to rock can be divided into two types: heating and cooling.According to acoustic emission monitoring of thermally induced granite in the heating and cooling process subjected to unconstrained conditions,the results indicate that: I) In the heating process,granite mainly exhibits elasto-plastic fracture in middle-high temperature. In the cooling process,thermal fracture of granite is dominated by brittle fracture in middle-low temperature. II) Thermal cracking mechanism is different between heating and cooling mode. In the heating process,thermal cracking mainly represents compression-shear mode induced by concentration of thermally compressive stress. In the cooling process,thermal cracking mainly performs tension-shear mode formed by local tensile stress concentration. III) By statistic analysis of acoustic emission data,the frequency and intensity of acoustic emission in the cooling process are higher than that in the heating process. In addition,thermal cracking in the cooling process is much more active than that in the heating process.
Temperature variation can cause uneven expansion( contraction) of mineral particles and result in thermal cracking in the rock. Temperature mode exposed to rock can be divided into two types: heating and cooling.According to acoustic emission monitoring of thermally induced granite in the heating and cooling process subjected to unconstrained conditions,the results indicate that: I) In the heating process,granite mainly exhibits elasto-plastic fracture in middle-high temperature. In the cooling process,thermal fracture of granite is dominated by brittle fracture in middle-low temperature. II) Thermal cracking mechanism is different between heating and cooling mode. In the heating process,thermal cracking mainly represents compression-shear mode induced by concentration of thermally compressive stress. In the cooling process,thermal cracking mainly performs tension-shear mode formed by local tensile stress concentration. III) By statistic analysis of acoustic emission data,the frequency and intensity of acoustic emission in the cooling process are higher than that in the heating process. In addition,thermal cracking in the cooling process is much more active than that in the heating process.
引文
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[2]张渊,曲方,赵阳升.岩石热破裂的声发射现象[J].岩土工程学报,2006,28(1):73-75.(Zhang Yuan,Qu Fang,Zhao Yangsheng.Acoustic emission phenomena of thermal cracking of sandstone[J].Chinese Journal of Geotechnical Engineering,2006,28(1):73-75.(in Chinese))
[3]武晋文,赵阳升,万志军,等.高温均匀压力花岗岩热破裂声发射特性实验研究[J].煤炭学报,2012,37(7):1111-1117.(Wu Jinwen,Zhao Yangsheng,Wan Zhijun,et al.Experimental study of acoustic emission of granite due to thermal cracking under high temperature and isostatic stress[J].Journal of China coal society,2012,37(7):1111-1117.(in Chinese))
[4]赵阳升,孟巧荣,康天合,等.显微CT试验技术与花岗岩热破裂特征的细观研究[J].岩石力学与工程学报,2008,27(1):28-34.(Zhao Yangsheng,Meng Qiaorong,Kang Tianhe,et al.Micro-CT experimental technology and meso-investigation on thermal fracturing characteristics of granite[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(1):28-34.(in Chinese))
[5]张渊,张贤,赵阳升.砂岩的热破裂过程[J].地球物理学报,2005,48(3):656-659.(Zhang Yuan,Zhang Xian,Zhao Yangsheng.Process of sandstone thermal cracking[J].Chinese Journal of Geophysics,2005,48(3):656-659.(in Chinese))
[6]左建平,周宏伟,方园,等.甘肃北山地区深部花岗岩的热开裂实验研究[J].岩石力学与工程学报,2011,30(6):1107-1115.(Zuo Jianping,Zhou Hongwei.Fang Yuan,et al.Experimental research on thermal cracking of deep granite in beishan region,gansu province[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(6):1107-1115.(in Chinese))
[7]左建平,谢和平,周宏伟,等.不同温度作用下岩石热开裂的实验研究[J].地球物理学报,2007,50(2):1150-1155.(Zuo Jianping,Xie Heping,Zhou Hongwei,et al.Experimental research on thermal cracking of sandstong under different temperature[J].Chinese Journal of Geophysics,2007,50(2):1150-1155.(in Chinese))
[8]赵阳升,万志军,张渊,等.岩石热破裂与渗透性相关性规律的试验研究[J].岩石力学与工程学报,2010,29(10):1970-1976.(Zhao Yangsheng,Wan Zhijun,Zhang Yuan,et al.Experimental study of related laws of rock thermal cracking and permeability[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):1970-1976.(in Chinese))
[9]Zhao Z H.Thermal influence on mechanical properties of granite:a microcracking perspective[J].Rock Mechanics and Rock Engineering,2016,49(3):747-762.
[10]杨昊天,徐进,王璐,等.花岗岩力学特性温度效应的试验研究[J].地下空间与工程学报,2013,9(1):96-101.(Yang Haotian,Xu Jin,Wang lu,et al.Experimental study on temperatures effect of the mechanical properties of granite[J].Chinese Journal of Underground Space and Engineering,2013,9(1):96-101.(in Chinese))
[11]万志军,赵阳升,董付科,等.高温及三轴应力下花岗岩体力学特性的实验研究[J].岩石力学与工程学报,2008,27(1):72-76.(Wan Zhijun,Zhao Yangsheng,Dong Fuke,et al.Experimental study on mechanical characteristics of granite under high temperatures and triaxial stresses[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(1):72-76.(in Chinese))
[12]Yavuz H,Demirdag S,Caran S.Thermal effect on the physical properties of carbonate rocks[J].International Journal of Rock Mechanics and Mining Science,2010,47:94-103.
[13]Dwivedi R D,Goel R K,Prasad V V R,et al.Thermomechanical properties of Indian and other granites[J].International Journal of Rock Mechanics and Mining Science,2008,45(3):303-315.
[14]左建平,周宏伟,方园,等.含双缺口北山花岗岩的热力耦合断裂特征试验研究[J].岩石力学与工程学报,2012,31(4):738-745.(Zuo Jianping,Zhou Hongwei,Fang Yuan,et al.Experimental research on fracture characteristics of double-noteched beishan granite under thermal-mechanical coupling effects[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(4):738-745.(in Chinese))
[15]支乐鹏,许金余,刘军忠,等.花岗岩高温后的超声特性及力学性能研究[J].地下空间与工程学报,2012,8(4):716-721.(Zhi Lepeng,Xu Jinyu,Liu Junzhong,et al.Research on ultrasonic characteristics and mechanical properties of granite under post-high temperature[J].Chinese Journal of Underground Space and Engineering,2012,8(4):716-721.(in Chinese))
[16]郤保平,赵阳升.600℃内高温状态花岗岩遇水冷却后力学特性试验研究[J].岩石力学与工程学报,2010,29(5):892-898.(Xi Baoping,Zhao Yangsheng.Experimental research on mechanical properties of water-cooled granite under high temperatures within 600℃[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(5):892-898.(in Chinese))
[17]Hall K,Thom C E.Thermal fatigue and thermal shock in bedrock:An attempt to unravel the geomorphic processes and products[J].Geomorphology,2014,206:1-13.
[18]Browing J,Meredith P,Gudmundsson A.Coolingdominated cracking in thermally stressed volcanic rocks[J].Geophysical Research Letters,2016,43:8417-8425.
[19]林睦曾.岩石热物理学及其工程应用[M].重庆:重庆大学出版社,1990.(Lin Muzeng.Rock thermal physics and engineering applications[M].Chongqing:Chongqing University Press,1990.(in Chinese))