花岗岩卸荷破坏全过程声发射特征试验
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摘要
利用MTS815混凝土与岩石力学试验系统和PCI-2三维定位实时监测系统对花岗岩卸荷破坏进行了声发射试验,得到了其卸荷破坏全过程变形特性和声发射特征,探讨了应力与应变、声发射数与应力、声发射率与应力、声发射数与时间以及声发射率与时间之间的关系.研究表明,岩石在卸荷方式下的破坏大多表现为脆性破坏,而且围压越大,脆性破坏特征越明显;对于1-1试件,破坏前在应力大于310MPa左右或在时间大于300s左右的范围内声发射数、声发射率开始出现激增现象,表明进入该阶段岩石内部破裂开始加速发育、扩展,最终导致岩石的破坏.研究成果对具有同类岩体的工程具有重要的参考价值.
An acoustic emission experiment on granite during unloading process is conducted through MTS815 system and PCI-2 three-dimensional real-time system.The characteristics of deformation and acoustic emission of the entire unloading process are obtained.The relationships between stress and strain,acoustic emission number and stress,acoustic emission rate and stress,acoustic emission number and time,acoustic emission rate and time are discussed.The research results show that the major damage mode during the unloading process of granite is brittle failure.The characteristic of brittle failure is more obvious with the confining pressure increasing.For the test sample 1-1,before the ultimate break-up,when the stress is greater than about 310 MPa or after the time of about 300 s,the emission number and emission rate demonstrate a rapid increase,showing that an accelerative development and expansion of the inner cracking,so as to lead to the final damage.The research results can provide important reference values to the engineering with the similar rock.
An acoustic emission experiment on granite during unloading process is conducted through MTS815 system and PCI-2 three-dimensional real-time system.The characteristics of deformation and acoustic emission of the entire unloading process are obtained.The relationships between stress and strain,acoustic emission number and stress,acoustic emission rate and stress,acoustic emission number and time,acoustic emission rate and time are discussed.The research results show that the major damage mode during the unloading process of granite is brittle failure.The characteristic of brittle failure is more obvious with the confining pressure increasing.For the test sample 1-1,before the ultimate break-up,when the stress is greater than about 310 MPa or after the time of about 300 s,the emission number and emission rate demonstrate a rapid increase,showing that an accelerative development and expansion of the inner cracking,so as to lead to the final damage.The research results can provide important reference values to the engineering with the similar rock.
引文
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[2]蒋宇,葛修润,任建喜.岩石疲劳破坏过程中的变形规律及声发射特性[J].岩石力学与工程学报,2004,23(11):1810-1814.
[3]付小敏.典型岩石单轴压缩变形及声发射特性试验研究[J].成都理工大学学报(自然科学版),2005,32(1):17-21.
[4]赵兴东,刘建坡,李元辉,等.岩石声发射定位技术及其实验验证[J].岩土工程学报,2008,30(10):1472-1476.
[5]许昭永,王彬,梅世蓉,等.岩石在破裂孕育过程中声发射变化特征的物理机制研究[J].中国地震,1994,10(3):293-302.
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