双轴受压花岗岩触发型岩爆试验研究

发布时间：2018-03-14 10:42

本文选题：岩石力学　切入点：岩爆　出处：《广西大学》2017年硕士论文　论文类型：学位论文

【摘要】：岩爆是高地应力条件下的一种剧烈的岩石动力破坏现象。在深部高地应力条件下,工程开挖扰动常常诱发严重的岩爆破坏。岩爆的发生通常伴随着岩石碎块高速猛烈弹射、抛出以及大量的能量释放,会给施工人员生命、施工设备安全以及工程进度带来严重的威胁。因此,对脆性岩石的岩爆进行研究是十分有必要的。此外,在实际工程中,很大一部分岩爆是由开挖爆破、机械钻凿、地震波等动力扰动荷载诱发的。对于水工隧洞洞室群之间的边墙、矿山的顶拱及底板等特殊结构处的花岗岩岩体常处于双向受压的状态,在动力扰动荷载作用下很容易诱发岩爆破坏。因此,有必要开展双轴受压花岗岩在不同动力扰动荷载作用下诱发岩爆的试验研究。本文利用自主研发的岩爆试验系统,采用长方体花岗岩为岩石试件,开展了二维动静组合岩爆试验,模拟了双向受压状态下不同扰动荷载诱发岩爆的全过程,研究了不同动力扰动荷载对岩爆的影响。采用变形测试系统、声发射系统、高速摄像系统等技术手段,对试验过程进行全方位、多角度的监测。对比分析了不同动力扰动荷载诱发岩爆及自发型岩爆的弹射过程和弹射动能、破坏形态、变形和损伤特性、声发射特征。试验结果表明:(1)动力扰动荷载对岩爆的强烈程度有重要影响。竖向静应力为110MPa时,强扰动荷载作用下岩爆的弹射动能是中扰动荷载作用下的7.6倍,弱扰动荷载没能触发岩爆的发生,弹射动能接近于0。竖向静应力为179MPa时,弱扰动岩爆的弹射动能高于自发型岩爆的弹射总动能,这说明静应力水平和动力扰动荷载强度越高,岩爆越容易被动力扰动触发,被触发岩爆的弹射动能越大。(2)岩石的破坏形态特征受动力扰动荷载的影响较大。自发型岩爆后母岩较为完整,裂纹细短;强扰动荷载下的母岩发生强烈的剪切破坏;弱扰动荷载下的母岩底部张拉、剪切裂纹完全贯通;中扰动荷载下的母岩发生严重膨胀,中部张拉、剪切裂纹完全贯通。这说明动力扰动荷载越强,岩爆后母岩的破坏程度越严重。此外,通过对比弹射碎块的特征,可以知道扰动荷载能够促进竖向裂纹的发育。(3)动力扰动荷载对试件发生岩爆破坏前竖向累积应变有明显影响。竖向静应力为11OMPa时,强扰动荷载作用下试件的竖向应变大于弱扰动荷载作用下的,小于中扰动荷载作用下的,这说明扰动荷载的强弱可以影响岩石发生破坏时的累积变形,且较强的扰动荷载更容易导致岩石产生更大的累积变形。竖向静应力为179MPa时,弱扰动荷载作用下岩爆试件的竖向应变明显高于竖向静应力为11OMPa时弱扰动荷载作用下试件的竖向应变,即初始静应力的提高有助于岩石累积变形的增大。对比自发型岩爆和弱扰动触发岩爆可知,前者的竖向应变小于后者,这说明在高应力条件下,即使微弱的扰动荷载也能使岩石产生更大的累积变形。(4)动力扰动荷载可以影响岩石的声发射特性。竖向静应力为110MPa时,强扰动荷载作用下试件的声发射绝对能量累积最大值低于中扰动荷载作用下试件的声发射绝对能量累积最大值,这表明岩石内部结构的损伤程度前者较后者要低,而前者的岩爆强度最大,由此说明低的能量耗散是诱发强烈岩爆的基本条件之一,而动力扰动荷载越强被触发的岩爆强烈程度越大。竖向静应力为179MPa时,弱扰动荷载作用下试件的声发射绝对能量累积最大值明显高于竖向静应力为110MPa时弱扰动荷载作用下试件的声发射绝对能量累积最大值和相近竖向静应力的自发型岩爆试件声发射绝对能量累积最大值,这说明静应力水平越高,被触发岩爆破坏的剧烈程度越大。
[Abstract]:Rock burst is a kind of high rock dynamic damage phenomenon under the condition of severe stress. In deep high stress conditions, the excavation disturbance often cause serious rockburst. The occurrence of rock burst is usually accompanied by a high speed heavy rock fragments ejection, thrown and a lot of energy release, will give the construction personnel life. The construction equipment safety and engineering progress bring serious threat. Therefore, the brittle rock rock burst research is very necessary. In addition, in the actual project, a large part of rock burst by excavation blasting, mechanical drilling, seismic wave dynamic disturbance induced by load. For hydraulic tunnel caverns the side wall, granite mine roof and floor of the special structure in biaxial compression state, the dynamic disturbance loads easily induce rockburst. Therefore, it is necessary to carry out the double embossing Experimental study on load induced rockburst granite under different dynamic disturbance. The test system based on independent research and development of rock burst, the rectangular granite rock specimen, carry out two-dimensional combined dynamic and static tests of rock burst, the simulation of biaxial compression under different disturbance process load induced rockburst, different dynamic disturbance effect of load on rock burst was studied. The deformation measurement system, acoustic emission system, high speed camera system technology, a full range of test process, monitoring point. Comparative analysis of different power load disturbance induced rockburst and the ejection process and ejection kinetic energy, hair rock burst failure and deformation the damage characteristics of acoustic emission characteristics. Experimental results show that: (1) the load has an important influence on the intensity of rock burst power disturbance. The vertical static stress is 110MPa, strong disturbance loads of rockburst dynamic ejection Can be 7.6 times the disturbance of load, the weak perturbation load failed to trigger the occurrence of rock burst, the ejection kinetic energy is close to 0. vertical static stress is 179MPa, weak disturbance of rock burst is higher than the total kinetic energy from the kinetic energy of the ejection ejection type of rock burst, this shows that the static stress level and dynamic disturbance load strength the higher, the more easily trigger rock burst triggered by dynamic disturbance, rock burst ejection greater kinetic energy (2). Effect of dynamic disturbance load damage characteristics of rock greatly. Spontaneous rock burst rock stepmother is complete, thin and short crack; strong disturbance loads rock strong shear failure weak disturbance; rock bottom loading tension, shear crack completely through disturbance loads; rocks serious expansion, the central tension, shear crack completely through. The dynamic load disturbance is strong, the extent of damage of rock burst after rock more serious. In addition, the The ejection ratio features pieces, can know the perturbation load can promote vertical crack development. (3) the dynamic disturbance load on specimens of rock burst occurred before the failure of the vertical strain accumulation has obvious effect. The vertical static stress is 11OMPa, strong disturbance load test is larger than the vertical strain a weak disturbance loads. Less than the disturbance of load, the load disturbance strength can influence the cumulative deformation of rock failure occurs when the load disturbance, and strong rock more easily lead to produce greater cumulative deformation. The vertical static stress of 179MPa, the weak disturbance test of vertical strain was significantly higher than that of vertical static stress is 11OMPa weak disturbance load test under the vertical strain explosion loading rock, initial static stress helps to improve the rock accumulated deformation increases. Since the contrast and weak disturbance triggered the rock burst type rock, the former The vertical strain is less than the latter, which shows that under high stress conditions, even if the perturbation load weak can also produce greater cumulative deformation of rocks. (4) the dynamic disturbance load can influence acoustic emission of rocks. The vertical static stress is 110MPa, strong disturbance load specimens AE absolute maximum energy disturbance loads of specimens of AE cumulative maximum value is lower than the cumulative, which indicates that the internal structure of rock damage degree of the former is lower, while the rock burst intensity, indicating that low energy dissipation is one of the basic conditions of induced strong rockburst, and dynamic disturbance load more strong rock burst triggered strong degree. The vertical static stress is 179MPa, weak disturbance loads of specimens of AE cumulative maximum value was significantly higher than that of the vertical static stress of 110MPa weak disturbance load. The maximum absolute value of the absolute energy accumulation of the acoustic emission and the similar vertical static stress of the specimen is the highest value of the absolute energy accumulation of the acoustic emission, which indicates that the higher the static stress level is, the more severe the triggered rock burst is.

【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU45

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