岩爆硬岩应力松弛特性试验研究
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摘要
针对硬岩应力松弛特性及监测研究的不足,基于全过程超声波监测,开展了具有岩爆倾向性的辉长岩试样单轴压缩峰前应力松弛试验,得出了硬岩峰前应力松弛特性和超声波波形规律,建立了应力松弛模型,定义了应力松弛能量耗散率指标,探讨了应力松弛过程的能量储耗,得出了基于应力松弛试验的岩石均质度的确定方法。结果表明,硬岩应力松弛过程经历了迅速衰减、逐渐衰减和稳定3个演化阶段,应力松弛度非常低;Burgers模型能较好的反映硬岩的应力松弛特性,可用于实际工程长期稳定性分析中;在加载应力水平为其单轴抗压强度的70%以内时,其应力松弛过程的波速未发生变化,首波波幅均在11～12mV之间起伏波动变化,可结合超声波监测揭示其应力松弛过程中的变形损伤演化进程,研究成果对硬岩长期稳定性分析、预测及岩爆监测预警具有很好的指导和借鉴意义。
Aiming at the deficiency of study on characteristics and monitoring of stress relaxation of hard rocks,an uniaxial compressive pre-peak stress relaxation test of gabbro samples with rock burst tendency was carried out based on the whole process of ultrasonic monitoring,the pre-peak stress relaxation characteristics.Therefore,the law of ultrasonic waveforms of hard rock was obtained,a stress relaxation model was established,the stress relaxation energy dissipation rate index was defined,the energy storage of stress relaxation process was discussed,and the determination method of rock homogeneity based on stress relaxation test was obtained.The results showed that the stress relaxation process experienced three stages of rapid decay,gradual decay and stabilization,and the degree of stress relaxation was very low.Burgers model could well reflect the stress relaxation characteristics of hard rock,and could be used in the long-term stability analysis of practical engineering.When the stress level was less than 70% of its uniaxial compressive strength,the wave speed during stress relaxation had no change,and the amplitude of the first wave fluctuated between 11 mV and 12 mV.Combined with ultrasonic monitor,the evolution process of deformation damage during stress relaxation could be revealed.The results of the study had a good guidance and reference significance for long-term stability analysis and prediction of hard rock,as well as rock burst monitoring and early warning.
Aiming at the deficiency of study on characteristics and monitoring of stress relaxation of hard rocks,an uniaxial compressive pre-peak stress relaxation test of gabbro samples with rock burst tendency was carried out based on the whole process of ultrasonic monitoring,the pre-peak stress relaxation characteristics.Therefore,the law of ultrasonic waveforms of hard rock was obtained,a stress relaxation model was established,the stress relaxation energy dissipation rate index was defined,the energy storage of stress relaxation process was discussed,and the determination method of rock homogeneity based on stress relaxation test was obtained.The results showed that the stress relaxation process experienced three stages of rapid decay,gradual decay and stabilization,and the degree of stress relaxation was very low.Burgers model could well reflect the stress relaxation characteristics of hard rock,and could be used in the long-term stability analysis of practical engineering.When the stress level was less than 70% of its uniaxial compressive strength,the wave speed during stress relaxation had no change,and the amplitude of the first wave fluctuated between 11 mV and 12 mV.Combined with ultrasonic monitor,the evolution process of deformation damage during stress relaxation could be revealed.The results of the study had a good guidance and reference significance for long-term stability analysis and prediction of hard rock,as well as rock burst monitoring and early warning.
引文
[1]李铀,朱维申,彭意,等.某地红砂岩多轴受力状态蠕变松弛特性试验研究[J].岩土力学,2006,27(8):1248-1252.
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[6]于怀昌,周敏,刘汉东,等.粉砂质泥岩三轴压缩应力松弛特性试验研究[J].岩石力学与工程学报,2011,30(4):803-811.
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[8]于怀昌,赵阳,刘汉东,等.三轴应力作用下水对岩石应力松弛特性影响作用试验研究[J].岩石力学与工程学报,2015,34(2):313-322.
[9]张泷,刘耀儒,杨强.基于内变量热力学的岩石蠕变与应力松弛研究[J].岩石力学与工程学报,2015,34(4):755-762.
[10]刘志勇,肖明砾,谢红强,等.基于损伤演化的片岩应力松弛特性[J].岩土力学,2016,37(S1):101-107.
[11]刘传孝,王龙,刘星辉,等.深埋煤层应力松弛状态演化试验与动力学分析[J].岩土力学,2016,37(6):1588-1596.
[12]刘圣,李树清,袁越.三轴压缩下红砂岩峰后应力松弛特性试验研究[J].矿业工程研究,2017,32(2):49-53.
[13]张海龙,许江,大久保诚介,等.河津凝灰岩广义应力松弛特性及数值模拟研究[J].岩土力学,2017,38(4):1089-1096.
[2]熊良宵,杨林德,张尧.绿片岩多轴受压应力松弛试验研究[J].岩土工程学报,2010,32(8):1158-1165.
[3]曹平,郑欣平,李娜,等.深部斜长角闪岩流变试验及模型研究[J].岩石力学与工程学报,2012,31(S1):3015-3021.
[4]田洪铭,陈卫忠,赵武胜,等.宜-巴高速公路泥质红砂岩三轴应力松弛特性研究[J].岩土力学,2013,34(4):981-986.
[5]刘昂,沈明荣,蒋景彩,等.基于应力松弛试验的结构面长期强度确定方法[J].岩石力学与工程学报,2014,33(4):1916-1923.
[6]于怀昌,周敏,刘汉东,等.粉砂质泥岩三轴压缩应力松弛特性试验研究[J].岩石力学与工程学报,2011,30(4):803-811.
[7]于怀昌,李亚丽,刘汉东.粉砂质泥岩常规力学、蠕变以及应力松弛特性的对比研究[J].岩石力学与工程学报,2012,31(1):60-69.
[8]于怀昌,赵阳,刘汉东,等.三轴应力作用下水对岩石应力松弛特性影响作用试验研究[J].岩石力学与工程学报,2015,34(2):313-322.
[9]张泷,刘耀儒,杨强.基于内变量热力学的岩石蠕变与应力松弛研究[J].岩石力学与工程学报,2015,34(4):755-762.
[10]刘志勇,肖明砾,谢红强,等.基于损伤演化的片岩应力松弛特性[J].岩土力学,2016,37(S1):101-107.
[11]刘传孝,王龙,刘星辉,等.深埋煤层应力松弛状态演化试验与动力学分析[J].岩土力学,2016,37(6):1588-1596.
[12]刘圣,李树清,袁越.三轴压缩下红砂岩峰后应力松弛特性试验研究[J].矿业工程研究,2017,32(2):49-53.
[13]张海龙,许江,大久保诚介,等.河津凝灰岩广义应力松弛特性及数值模拟研究[J].岩土力学,2017,38(4):1089-1096.