单向循环加载下花岗岩力学特性及红外分析

Mechanical properties and infrared analysis of granite under uniaxial cyclic loading

为了探究单向循环加卸载作用对花岗岩力学特性的影响,开展了室内循环加卸载试验。选择5次和10次循环及12%,24%,36%,48%和60%的强度振幅对花岗岩进行循环加卸载预处理,进而测试其强度,并同步进行红外AIRT检测、红外热成像分析及温度场的频数直方图分析。研究结果表明:循环加卸载对岩石起先加强后削弱的作用,36%振幅10次循环预处理条件下的花岗岩综合性能较好;岩石破坏由局部应力集中所致,并揭示出岩石破坏伴随着能量积聚到释放过程。说明循环加卸载在一定条件下存在积极效应,且红外检测对岩石破坏的应力集中特性及灾害演化研究有较好的优越性。

In order to investigate the effect of uniaxial cyclic loading and unloading on the mechanical properties of granite,the laboratory tests of cyclic loading and unloading were carried out.The pretreatment of cyclic loading and unloading was conducted on the granite with the cycle number of 5 and 10 and the intensity amplitude of 12%,24%,36%,48%and 60%,thus its strength was tested,and the infrared AIRT detection,the infrared thermal imaging analysis and the frequency histogram analysis of temperature field were carried out synchronously.The results showed that the cyclic loading and unloading played the effect of strengthening first and then weakening on the rock,and the comprehensive performance of granite was better under the conditions of pretreatment with the intensity amplitude of 36%and the cycle number of 10.The rock failure was caused by the local stress concentration,and the process of rock failure along with the energy accumulation to energy release was revealed.It showed that the cyclic loading and unloading has the positive effect under certain conditions,and the infrared detection has better research advantage for the stress concentration characteristics and disaster evolution of rock failure.