宣东二矿瓦斯优质通道构建方法研究

发布时间：2017-12-28 05:30

本文关键词：宣东二矿瓦斯优质通道构建方法研究　出处：《中国矿业大学(北京)》2016年博士论文　论文类型：学位论文

【摘要】：瓦斯作为煤炭主要的伴生资源,过去一直是威胁煤炭安全生产的重要因素之一,也是被严重浪费和低估的一种资源。随着绿色集约化煤炭开采越来越被关注,煤与瓦斯共采势在必行。本文以宣东二矿为工程背景,采用理论分析,数值模拟,现场监测等方法和手段,针对煤与瓦斯共采理论及技术这一热点研究问题,研究了钻孔围岩“蝶形塑性区”形成的力学机制,以钻孔围岩“蝶形塑性区”形成的力学机制为基础,研究了瓦斯优质通道重构的关键采煤干预方法和关键人工通道的干预方法,并对宣东二矿302工作面瓦斯抽采浓度进行了全过程监测,研究了瓦斯浓度与工作面距离钻场的关系,验证了钻孔围岩“蝶形塑性区”的合理性。获得了以下主要研究成果:(1)以弹塑性力学中的圆孔问题为基础,结合塑性力学的偏应力理论,建立了钻孔围岩“蝶形塑性区”理论模型,揭示了钻孔围岩“蝶形塑性区”形成的力学机制和分布规律,为构建瓦斯优质通道提供了理论依据;(2)以钻孔围岩“蝶形塑性区”理论为基础,研究了采矿活动形成的应力环境对钻孔围岩蝶形塑性区的影响规律,提出了瓦斯优质通道的概念,建立了通过合理规划采矿活动中的工作面长度,工作面高度和工作面煤柱尺寸等参数构建瓦斯优质通的关键采煤干预方法;(3)以宣东矿瓦斯抽采活动为例,对比分析了该矿瓦斯抽采钻孔在经历采动影响和未经历采动影响下的瓦斯浓度规律,验证了基于钻孔围岩“蝶形塑性区”理论提出的瓦斯优质通道构建方法的合理性。以弹塑性力学中的圆孔问题为基础,结合塑性力学的偏应力理论,建立了钻孔围岩“蝶形塑性区”理论模型,以此为基础,揭示了钻孔围岩“蝶形塑性区”形成的力学机制和分布规律,为构建瓦斯优质通道提供了理论依据,得到了如下主要结论:(1)建立了钻孔围岩理论力学模型,通过分析力学模型,得到了钻孔围岩在均匀应力场和非均匀引力场下偏应力解;得到了钻孔围岩偏应力场的分布规律,即巷道埋深和最大与最小主偏应力呈现正比例关系,围岩位置极坐标(r,θ)和最大与最小主偏应力分别呈现横“八”字状和横“陀螺”状分布;(2)得到了钻孔围岩塑性区半径下非等压应力场中的计算公式,揭示了在非等压应力场中,钻孔围岩“蝶形塑性区”分布规律;(3)分析了侧压系数λ、内聚力c、内摩擦角φ和钻孔半径r对钻孔围压塑性区的分布的影响。其中当侧压系数λ≠1时,钻孔围岩塑性区均呈现“蝶”状分布,并且λ/1(当λ1时)或者1/λ(当λ1时)的比值越大,钻孔围岩塑性区的“蝶”状分布越明显;内聚力c越小钻孔围岩塑性区的范围越大,并且其“蝶”状分布越明显;内摩擦角φ越小钻孔围岩塑性区的范围越大,并且其“蝶”状分布越明显;钻孔半径越大钻孔围岩塑性区的范围越大,并且其“蝶”状分布越明显。以钻孔围岩“蝶形塑性区”理论为基础,研究了采矿活动形成的应力环境对钻孔围岩蝶形塑性区的影响规律,提出了瓦斯优质通道的概念,建立了通过合理规划采矿活动中的工作面长度,工作面高度和工作面煤柱等参数构建瓦斯优质通的关键采煤干预方法,数值模拟结果表明:(1)在工作面长度小于200m或大于200m时,高应力比值带形状为马鞍形或驼峰形,此类高应力比值带不利于瓦斯抽采钻孔的布置。当工作面长度在200m时,高应力比值带为水平椭圆状分布,有利于瓦斯钻孔的布置,瓦斯钻孔可以大部分布置在高应力比值带内。(2)在煤柱下方底板岩层并未出现明显的应力卸载区域,基本不受开采的影响,不能形成钻孔围岩出现蝶形塑性区的应力环境,不利于钻孔围岩塑性区的扩展,因此瓦斯抽采钻孔应尽量避免布置于煤柱底板区域。(3)高应力比值带的形态不会随着工作面采高变化而发生较大变化,高应力比值带的最大比值并不会随着采高的变化而发生明显的改变。同时,高应力比值带的位置不随采高发生较大的变化。因此,采高不会对高应力比值带的大小和分布范围产生较大的影响。(4)工作面长度和工作面煤柱尺寸相比于工作面采高对高应力比值带的影响程度要大。因此,对于通过规划采煤参数以达到构建瓦斯优质通时,可主要考虑从规划工作面长度和工作面煤柱尺寸两方面入手。瓦斯优质通道重构方法包括关键采煤方法干预方法和关键人工通道的干预方法。关键采煤干预方法通过合理规划采矿工程活动,构建了有利于构建瓦斯优质通道的应力环境,关键人工通道的干预方法主要包括抽采钻孔布置层位和抽采钻孔布置间距。利用钻孔围岩塑性区计算方法,探究了钻孔布置层位的确定方法及合理的钻孔间距,研究结果表明:(1)在高应力比值带内,不同岩性条件下钻孔围岩塑性区均呈现蝶形形态。当其他参数条件一定时,钻孔围岩塑性区边界最大半径与岩石黏聚力成负相关,在岩石黏聚力增加到一定值后,最大半径变化趋于缓慢;当其他参数条件一定时,钻孔围岩塑性区边界最大半径与岩石内摩擦角成负相关,在岩石内摩擦角增加到一定值后,最大半径变化趋于缓慢。(2)钻孔合理层位选择分两种情况:当下开采煤层煤质较硬时,钻孔布置在煤层中;当下开采煤层煤质较软时,钻孔布置在邻近下开采煤层的稳定岩层中。(3)钻孔间距依据钻孔围岩塑性区边界最大半径及所对应的方位角确定。钻孔布置在煤层中时,钻孔间距为:maxH?2Rcos?;钻孔布置在邻近稳定岩层时,钻孔间距为:maxH?2(h?d)/tan?。在研究钻孔围岩“蝶形塑性区”理论和瓦斯优质通道构建方法的基础上,以宣东矿瓦斯抽采活动为例,介绍了该矿的瓦斯抽采现状,对比分析了该矿瓦斯抽采钻孔在经历采动影响和未经历采动影响下的瓦斯浓度规律,验证了基于钻孔围岩“蝶形塑性区”理论提出的瓦斯优质通道构建方法的合理性,现场瓦斯浓度监测结果表明:(1)通过研究分析302工作面瓦斯抽采浓度发现:瓦斯浓度与工作面距离钻场的距离基本呈现出反比状态,即工作面距离钻场越远,瓦斯浓度越小,工作面距离钻场越近,瓦斯浓度越大。(2)瓦斯浓度与工作面距离钻场的距离的关系验证了钻孔围岩“蝶形塑性区”理论的合理性。工作面距离钻场较远时,钻孔处于原岩应力区,钻孔围岩周围几乎不产生塑性区,导致各个钻孔的瓦斯浓度较小;当工作面回采逐渐接近钻场时,抽采钻孔处于采动应力场形成的采动加载应力环境,钻孔围岩产生蝶形塑性区,有利于瓦斯的抽采,瓦斯浓度逐渐增大。本文研究得到的钻孔围岩“蝶形塑性区”理论,及在此基础之上提出的瓦斯优质通道重构的关键采煤干预方法和关键人工通道干预方法,为瓦斯抽采及煤与瓦斯共采提供了一种新思路和新方法。
[Abstract]:As one of the main associated resources of coal, gas has been one of the important factors that threaten the safety of coal production, and it is also a resource that is seriously wasted and underestimated. As the green intensive coal mining is becoming more and more concerned, coal and gas CO production is imperative. In this paper, Xuandong two mine as engineering background, using theoretical analysis, numerical simulation, field monitoring methods and means for coal and gas extraction a hot research problems in the theory and technology, the mechanical mechanism of the surrounding rock "butterfly plastic zone" formation, mechanism of formation in drilling surrounding rock "butterfly the plastic zone" as the foundation, study the intervention methods of gas quality channel reconstruction key mining intervention methods and key artificial channel, and the gas of two Xuandong mine 302 working face extraction concentration of the whole process of monitoring of gas concentration and the working relationship between distance drilling field, verify the rationality of drilling rock "butterfly plastic zone". The main research achievements are as follows: (1) the problem of elastic circular mechanics as the basis, combined with the theory of partial stress should be plastic mechanics, established the "butterfly drilling surrounding rock plastic zone" theory model, reveals the mechanics mechanism of the formation and distribution of surrounding rock of "butterfly plastic zone" that provides a theoretical basis for the construction of high quality gas channel; (2) the surrounding rock "butterfly plastic zone" as the theoretical basis, research the mining activities form stress environment influence law of plastic zone of surrounding rock of butterfly, put forward the concept of high quality gas channel, established by reasonable working face length planning in mining, mining key intervention methods work surface height and working face coal pillar size and other parameters to construct gas quality links; (3) in Xuandong mine as an example, a comparative analysis of the mine gas drainage drilling experience in mining influence and not The rule of gas concentration under the influence of mining has verified the rationality of the construction method of gas quality channel based on the "butterfly plastic zone" theory of borehole surrounding rock. The plastic hole problem in mechanics as the basis, combined with the theory of partial stress should be plastic mechanics, established the "butterfly drilling surrounding rock plastic zone" theory model, on this basis, reveals the mechanics mechanism of the formation and distribution of surrounding rock of "butterfly plastic zone", provides a theoretical basis for the construction of gas channel quality, the main conclusions are as follows: (1) established the theory of rock drilling model, through the analysis of the mechanical model, the surrounding rock in uniform stress field and non-uniform gravitational field under deviatoric stress solution; the drilling has partial rock stress field distribution, the depth of roadways and the maximum and minimum principal deviator stress presented in direct proportion to the relationship between rock position of polar coordinates (R, 0) and the maximum and minimum principal stress presents partial transverse "eight" with the word "top" and cross shaped distribution respectively; (2) the drilling rock plastic zone radius under field should be non isobaric force The calculation formula reveals the distribution rule of "butterfly plastic zone" in borehole surrounding rock in the non isobaric stress field. (3) the influence of lateral pressure coefficient lambda, cohesive force C, internal friction angle and radius r on the distribution of plastic zone in borehole surrounding pressure is analyzed. When the lateral pressure coefficient lambda = 1, drilling rock plastic zone showed a "Butterfly" shaped distribution, and a /1 (when 1) or 1/ (when lambda lambda 1) the ratio is higher, the drilling rock plastic zone "Butterfly" shaped distribution is more obvious; the smaller the C cohesion surrounding rock plastic zone is larger, and the "Butterfly" shaped distribution is more obvious; the internal friction angle is smaller in surrounding rock plastic range is larger, and the "Butterfly" shaped distribution is more obvious; the larger the radius of borehole drilling surrounding rock plastic zone is larger, and the butterfly "" distribution is more obvious. The surrounding rock of "butterfly plastic zone" as the theoretical basis, research the mining activities form stress environment influence law of plastic zone of surrounding rock of butterfly, put forward the concept of high quality gas channel, set up the length of the working face through reasonable planning of mining activities in the key mining work surface height and intervention methods the working face of coal pillar construction parameters such as gas quality through the numerical simulation results show that: (1) in the working face length is less than 200m or greater than 200m, high stress ratio with shape of saddle or hump shaped, such high stress ratio is not conducive to the gas drainage borehole layout. When the length of the working face is 200m, the ratio of the high stress ratio is horizontal elliptical, which is favorable for the layout of gas drilling, and the gas drilling can be mostly arranged in the high stress ratio zone. (2) did not show significant stress unloading region in the coal pillar floor strata under the influence of mining, no, can not form a butterfly shaped plastic zone stress environment of surrounding rock, is not conducive to the expansion of surrounding rock plastic zone, so the gas drainage drilling should avoid placed on the coal pillar floor area. (3) the shape of high stress ratio does not change greatly along with the change of mining height. The maximum ratio of high stress ratio does not change obviously with the change of mining height. At the same time, the position of the high stress ratio zone does not vary greatly with the mining height. Therefore, the height of the high stress ratio will not have a great influence on the size and distribution of the high stress ratio zone. (4) the impact of the length of the working face and the size of the working face coal pillar on the high stress ratio zone is larger than the height of the working face. Therefore, for planning the mining parameters to achieve gas quality, we can mainly consider two aspects: the length of the planning face and the pillar size of the working face. The method of reconstruction of gas high quality channel includes the intervention method of key mining method and the intervention method of key artificial channel. The key coal mining intervention method, through reasonable planning of mining engineering activities, has constructed a stress environment conducive to the construction of gas quality passageway. The key artificial channel intervention methods mainly include the layout of drainage holes and the spacing between drainage holes.
【学位授予单位】：中国矿业大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TD712.6

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