注水条件下具有冲击倾向煤体破坏前兆红外声发射特性研究

发布时间：2018-03-07 20:15

本文选题：煤层注水　切入点：冲击倾向性　出处：《黑龙江科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：在具有冲击倾向性煤层开采中,通常采用煤层注水卸压的方式来保证安全生产,但是生产过程中采用此方式的煤体在高应力作用下局部有时依然有冲击事故发生。为了减少冲击危险事故的发生,提高局部危险区域的可预测性和可预警性,对局部危险区域注水煤体失稳前兆信息的监测研究显得尤为关键。针对上述问题,本文通过接触式声发射设备和非接触式红外热像设备对具有冲击倾向性注水煤体(自然吸水状态煤体、饱和吸水状态煤体和天然含水状态煤体)进行单轴荷载组合监测试验,以求从内外两方面来监测煤样失稳破坏的演化过程,从而揭示具有冲击倾向煤体局部危险区域受力失稳前红外辐射和声发射前兆变化规律,通过试验研究本文取得了如下主要研究成果:(1)煤样结构失稳前声发射演化过程大致可分为三个阶段,声发射平静期、声发射弱活跃期和声发射强活跃期。煤样吸水量越大,相同荷载下煤样承载时间缩短,局部失稳现象出现越早,声发射突增点也出现越早。煤样失稳前声发射信号突增明显且具有一段平静期。此现象的出现可作为煤样失稳前兆的判断依据。(2)注水煤样AIRT-时间演化和应力-时间演化趋势相似,煤样结构失稳前AIRT先于结构失稳应力下降而下降,吸水量越大这种趋势越明显。煤样失稳前红外热像的红外前兆异常区显现明显。煤样吸水率越大红外热像异常点与周围环境温差越小,但是红外异常点显现越明显。首次红外异常区的出现可作为煤样失稳前兆的判断依据。(3)通过对比分析注水煤体在结构失稳演化过程中的声发射和红外辐射特征信息可知:声发射信号增多只知道损伤加剧但不知何时煤样失稳破坏,虽然红外热像的出现时间比AE信号出现晚,但是,它却比AE信号结束早。因此,红外异常点、带或面的出现则能更加直观和明显的预示煤样失稳破坏。利用声发射和红外热像特征参数建立了煤体损伤模型,从内外两方面分析了注水煤样损伤演化规律。通过实验研究发现两种监测手段可优势互补,其组合监测能较好的预测煤样失稳破坏。
[Abstract]:In the mining of coal seam with percussive tendency, coal seam water injection and pressure relief is usually used to ensure safe production. However, in order to reduce the occurrence of the dangerous impact accidents and improve the predictability and early warning of the local dangerous areas, the coal bodies which adopt this way in the process of production sometimes still have impact accidents under high stress. It is very important to monitor and study the precursor information of coal body instability in local dangerous area. In this paper, contact acoustic emission equipment and non-contact infrared thermal imaging equipment are used to test the uniaxial load combination monitoring of coal body with impact tendency (natural absorbent coal, saturated absorbent coal and natural water-bearing coal). In order to monitor the evolution process of instability and failure of coal samples from both inside and outside, this paper reveals the law of infrared radiation and acoustic emission precursor before the local dangerous area of coal body with impact tendency. The main research results of this paper are as follows: (1) the evolution process of acoustic emission (AE) before instability of coal sample structure can be divided into three stages: acoustic emission quiet period, acoustic emission weak active period and acoustic emission strong active period. Under the same load, the loading time of coal sample is shortened, and the local instability occurs earlier. The more early the acoustic emission burst occurs, the more obvious the acoustic emission signal increases before the coal sample instability and has a quiet period. This phenomenon can be used as the basis for judging the precursor of coal sample instability. 2) AIRT- time evolution and stress-time of injected coal sample. The trend of evolution is similar. Before the instability of coal sample structure, the AIRT decreases before the structural instability stress decreases. The larger the water absorption is, the more obvious this trend is. The more the water absorption rate of coal sample, the smaller the temperature difference between the abnormal point of infrared thermal image and the surrounding environment. However, the more obvious the infrared anomaly is, the more obvious it is. The appearance of the first abnormal infrared region can be used as the basis for judging the precursor of coal instability. Through the comparative analysis of acoustic emission and infrared radiation characteristic information of injected coal in the evolution process of structural instability, this paper makes a comparative analysis of the characteristics of acoustic emission and infrared radiation in the process of structural instability evolution. Information: an increase in acoustic emission signals is known only to increase the damage but not to know when the coal sample is unstable and destroyed. Although the infrared thermal image appears later than the AE signal, it is earlier than the AE signal. Therefore, the infrared anomaly, The appearance of belt or surface can predict the instability and failure of coal sample more intuitively and obviously. The damage model of coal body is established by using the characteristic parameters of acoustic emission and infrared thermal image. The law of damage evolution of injected coal samples is analyzed from internal and external aspects. It is found that the two monitoring methods can complement each other in their advantages and their combined monitoring can better predict the instability and failure of coal samples.
【学位授予单位】：黑龙江科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD324

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