钻孔瓦斯抽采半径的确定方法及实践_唐兵

2012年8月

矿业安全与环保

第39卷第4期

钻孔瓦斯抽采半径的确定方法及实践

唐

1，231，2兵，司春风，孟贤正

（1．瓦斯灾害监控与应急技术国家重点实验室，重庆400037；2．中煤科工集团重庆研究院瓦斯研究分院，重庆400037；

3．皖北煤电集团有限责任公司，安徽宿州234000）

摘要：钻孔瓦斯抽采半径主要与煤层瓦斯含量、透气性系数、抽采钻孔直径及负压、抽采目的和时间

等因素有关。传统的抽采半径确定方法对于透气性较好、煤层测压条件较佳时可能得到考察结果，但效

测定成功率极低，实用性差。为此，在已知煤层瓦斯含量基础上，选用直接率较低；当煤层透气性差时，

测定钻孔瓦斯动态抽采流量，按照抽采目标确定抽采率进而确定钻孔不同抽采时间的抽采半径。实践表明，该方法具有较强的实用性。

关键词：钻孔；抽采半径；瓦斯压力降低法；抽采瓦斯统计法

+

中图分类号：TD712．62文献标志码：B 文章编号：1008－4495（2012）04－0043－03确定煤层瓦斯合理抽采半径是实现矿井抽采达

标最重要的技术工作之一。合理的抽采半径或抽采钻孔间距，是通过在一定条件下充分利用允许的预抽时间，减少钻孔工程量，提高抽采效率的优化参数获取。传统的抽采半径确定方法，对于透气性较好、煤层测压条件较佳时可能得到考察结果，但其测试

［1－2］

；当煤层透气性差时测定成功率极低，效率低实

用性差。目前，高瓦斯、煤与瓦斯突出矿井在贯彻《防治煤与瓦斯突出规定》、《煤矿瓦斯抽采达标规定》过程中迫切需要简单易行，便于推广应用的钻孔抽采半径确定的新方法。为此，在已知煤层瓦斯含量的基础上，采用直接测定钻孔瓦斯动态抽采流量的方法来确定钻孔不同抽采时间的抽采半径。

式中

2

2πm λ（p 20－p r 0）=（1－e －αt ）

R

αp std ln

r 0

（4）

q 0———钻孔瓦斯涌出初始强度，m 3/（min ·m 2）；q' ———t 时刻的钻孔瓦斯涌出强度，m 3/（min ·m 2）；q ———t 时刻的钻孔瓦斯涌出量，m 3/（min ·m 2）；Q ———在t 时间内钻孔瓦斯抽采总量，m 3；t ———钻孔内瓦斯流动时间，min ；——煤层透气性系数，m 2/（MPa 2·d ）；λ—

p 0———煤层原始瓦斯压力，MPa ；p r0———钻孔内瓦斯压力，MPa ；p std ———标准状态下的大气压，MPa ；R ———钻孔瓦斯流动场的影响半径，m ；r 0———钻孔半径，m ；

m ———煤层厚度或钻孔穿煤长度，m ；——钻孔瓦斯流量衰减系数，d α—

－1

1钻孔瓦斯抽采基础理论

一般情况，煤层的透气性及钻孔瓦斯补给量是

有限的，煤层的瓦斯流动性质是非稳定流动，即随着流动时间的增长，钻孔的瓦斯涌出强度、瓦斯流量会衰减。根据煤层瓦斯流动理论，穿层抽采钻孔的瓦

［3］

斯流动表达式如下：

22λ（p 0－p r0）q 0=

R

r 0p std ln

r 0

。

钻孔瓦斯抽采半径主要与煤层瓦斯含量、透气性系数、抽采钻孔直径及负压、抽采目的及时间等因素有关。因此，在煤层瓦斯含量测定基础上，根据抽采目的，测定出钻孔瓦斯抽采能力，通过三者之间的关系计算分析，就可确定出钻孔的抽采半径。

由式（4）可知，煤层透气性系数越大、钻孔直径抽采负压越大、抽采时间越长、煤层厚度越大，越大、

则钻孔抽采瓦斯流量越大。一般情况下，在特定的区域，钻孔直径、抽采负压确定后，煤层厚度、透气性系数可认为是一定值，因此钻孔抽采瓦斯的能力与

－t

抽采时间呈（1－e α）关系，从而根据钻孔抽采能力

（1）（2）（3）

q' =q 0e －αt

q =2πr 0mq' =2πr 0mq 0e －αt

t 2πr 0m q 0

Q =q d t =（1－e －αt ）

0α

∫

收稿日期：2011－09－30；2012－05－07修订

与抽采半径的关系就可分析得出钻孔不同抽采时间

所对应的抽采半径。

·43·

2

2．1

矿业安全与环保

标规定的瓦斯抽采率：

η5=

W －W j

×100%。W

确定钻孔瓦斯抽采半径的方法

瓦斯抽采率确定

《防治煤与瓦斯突出规定》、《煤矿瓦斯抽按照

确定的抽采率η=max （η1，η2，η3，η4，η5）。2．2

钻孔瓦斯抽采能力测试

钻孔瓦斯抽采能力受诸多因素影响，但在特定的煤层区域，可直接测定一组钻孔瓦斯动态抽放流q 2，q 3，量，得出不同时间对应的抽采瓦斯流量｛q 1，…，q n ｝。钻孔瓦斯涌出强度随时间一般呈负指数衰减，根据考察的抽采瓦斯流量数据组可通过最小二

－t

乘法拟合得出钻孔t 时刻的瓦斯抽采流量q t =q 0e α

采基本指标》的相关要求，必须将控制范围内煤层的

3

瓦斯含量降到8m /t以下、瓦斯压力降到0．74MPa

以下，或瓦斯含量降到煤层始突深度的瓦斯含量以瓦斯压力降到煤层始突深度的瓦斯压力以下，则下、

可由以下几种方法确定煤层抽采达标的瓦斯抽采率。

1）将残余瓦斯含量降到8m 3/t时的抽采率：

W －8

×100%；η1=

W 2）将残余瓦斯含量降到始突深度处煤层瓦斯含量时的抽采率：

W －W 始突

×100%；η2=

W

3）将残余瓦斯压力降到0．74MPa 时的抽采率：η3=

W －W p 0．74

×100%；W

的关系式，即得出钻孔瓦斯抽采流量随时间衰减的曲线，通过积分Q t =2．3

∫q e

t

－αt

d t ，可确定钻孔单孔不

同抽采时间的抽采瓦斯总量Q 单。

钻孔抽采半径计算

在煤层瓦斯含量一定的抽采煤层区域，根据抽采目的，确定抽采区域需抽采瓦斯总量：

Q 抽总=L 1L 2h ρW η式中

L 1、L 2———瓦斯含量相同的抽采钻孔控制区m ；理论计算时可取L 1=L 2=L ；域长度、宽度，h ———抽采钻孔控制区域煤层厚度，m ；——抽采钻孔控制区域煤层密度，t /m3。ρ—

抽采区域需布置的抽采钻孔数量按下式计算：N =Q 抽总/Q单

m 3。式中Q 单为不同抽采时间统计的单孔抽采总量，

根据测试数据直接累计得出单孔抽采总量，或根据测试数据拟合抽采衰减负指数曲线，再进行积分求解出不同时间的单孔抽采总量。最后，将N 个即可解算出一钻孔平均分布在抽采钻孔控制区域，

。定抽采时间下的钻孔抽采半径：R =L /（24）将残余瓦斯压力降到始突深度的瓦斯压力时的抽采率：

η4=式中

W －W p 始突

×100%。W

W ———煤层原始瓦斯含量，m 3/t；

W 始突———始突深度的煤层瓦斯含量，m 3/t；W p 0．74———瓦斯压力为0．74MPa 时的煤层瓦m 3/t；斯含量，W p 始突———瓦斯压力为始突深度的瓦斯压力m 3/t。时的煤层瓦斯含量，

5）矿井瓦斯抽采不仅要防治煤与瓦斯突出，对于已消除突出危险性的煤层以及某些高瓦斯煤层回采工作面为了治理瓦斯涌出，仍需进行瓦斯抽采，以《煤矿瓦斯抽采基本指标》对采煤工作面回采前满足

煤的可解吸瓦斯量应达指标，见表1。

表1

采煤工作面回采前煤的可解吸瓦斯量应达指标

工作面日产量/t

≤10001001～25002501～40004001～60006001～80008001～10000＞10000

可解吸瓦斯量W j /（m 3/t）

≤8．0≤7．0≤6．0≤5．5≤5．0≤4．5≤4．0

3

3．1

现场试验考察

试验区域概况

试验区位于祁东煤矿三采区西翼深部7138工

作面。71煤层被夹矸分为两层，中间夹矸厚度为3．5～5．0m ，煤层不稳定。71煤层伪顶为局部存在厚约0．1m 的炭泥，底板为灰—深灰色泥岩；直接顶为灰—深灰色泥岩、粉砂岩及砂泥岩互层，局部无直平均厚4．22m ；老顶为浅灰—灰白色细粒石英接顶，

中砂岩，该岩层含水较丰富。该区域实测71煤层砂岩、

3

原始瓦斯压力为2．2MPa ，瓦斯含量为10．28m /t，透气22

性系数为0．006737～0．06849m /（MPa ·d ），钻－1孔瓦斯流量衰减系数为0．25～0．28d 。

按采煤工作面回采前煤的可解吸瓦斯量应达指·44·

3．2

抽采钻孔布置

矿业安全与环保

将煤层瓦斯压力降到域71煤层瓦斯经过抽采后，

0．74MPa 以下，表明71煤层区域措施有效；则相应

3

的残余瓦斯含量为6．26m /t。

在7138工作面底板抽采巷绕道设计钻孔考察71煤层抽采半径，预抽钻孔孔底间距10m ，孔径91mm ；同时，6号预抽钻孔两端间距分别分别在2、

#

2#、3#、4#测压钻孔来考为8m 和5m 位置，布置1、

穿层钻孔抽采区域（L =100m ）71煤层瓦斯压

3

对应原始瓦斯含量为10．28m /t，则力为2．2MPa ，

验证抽采半径。钻孔布察不同抽采时间变化情况，

置见图1，钻孔参数见表2。先施工测压钻孔测定煤层原始瓦斯压力，待瓦斯压力上升稳定后，再施工抽考察瓦斯压力变化情况

。采钻孔进行抽采，

Q 抽按下式计算：

Q 抽=L 2h ρ（W －6．26）=1002×1．9×1．3×（10．28－6．26）=99294m 3。

3．4．1

根据统计累计流量计算抽采半径

根据流量观测数据计算得到穿层钻孔预抽瓦斯

3

时间为30d 时的抽采瓦斯统计总量Q 单为529．3m ；

因此控制L ·L 区域内所需的钻孔个数：N =Q 抽/Q单=99294/529．3≈188。

穿层钻孔预抽30d 瓦斯抽采半径：R =3．4．2

图1表2

钻孔类别

编号1，3，54，62，

L

2根据拟合流量计算抽采半径

=

100

=3．65m 。

2［3］

钻孔瓦斯日抽采量呈负指数规律递减

71煤层抽采半径考察钻孔布置平面图71煤层抽采半径考察钻孔施工参数

孔径/mm 9175

倾角/（°）837171

方位角垂直71煤层底板抽采巷绕道

钻深/m 40．846．046．0

备

注

，钻孔

瓦斯抽采量与时间的拟合关系曲线见图2

。

抽采钻孔

过71煤层顶板0．5m 终孔间距10m 过71煤层顶板0．5m

测压钻孔1#—4#

图2钻孔日抽采瓦斯衰减量拟合曲线

3．3

钻孔瓦斯抽采统计

在抽采过程中，对钻孔瓦斯浓度、流量进行现场

表3

钻孔瓦斯抽采总量统计

抽采钻孔φ（CH 4）/

%[1**********]433

单孔瓦斯流量/（m /min）0．25120．20510．13990．14860．16320．14150．17920．11460．11110．1111

3

由图2可见，数据相关性强，其衰减负指数曲线能有效代表钻孔单孔抽采瓦斯规律，可根据该抽采衰减负指数曲线公式积分计算钻孔拟合抽采半径：

Q t =

观测，结果见表3。

日期

累计天数[**************]

单孔抽采瓦斯纯量/（m /d）61．544．328．221．418．816．312．96．64．84．8

3

∫45．527e

t

－0．0819t

d t

=（

45．52745．527－0．0819t

－e ）

0．08190．0819

2010－10－112010－10－132010－10－152010－10－172010－10－182010－10－212010－10－252010－10－302010－11－072010－11－10

根据上式计算，钻孔抽采60d 时的拟合量已经接近极限抽采量。利用拟合抽采衰减负指数曲线计算的71煤层预抽钻孔抽采半径的结果见表4。

表4

抽采时间/

d 3060∞

71煤层预抽钻孔抽采半径计算结果

单孔抽采总量/m3508．25551．80555．89

钻孔个数196180179

抽采半径/

m 3．573．733．74

极限半径备注

3．4钻孔瓦斯抽采半径分析

《防治煤与瓦斯突出规定》根据的要求，试验区

（下转第48页）

·45·

2012年8月

矿业安全与环保

第39卷第4期

过充填支架适应倾角，难以满足采空区矸石充实率要求。为此将工作面切眼布置于靠近采区下山侧，采用仰采俯充预留两巷前进式充填开采，矸石充实率达到要求，确保了充填效果。3．2

顶板稳定性

采空区矸石充填率和压实率是影响充填开采覆

［4］

岩破坏控制效果的关键因素。在煤层顶板稳定的条件下，工作面支架拉移后，采空区内矸石充填率接

2MPa 的压力能够使矸石充填体压实，近100%，确保充填质量。

1312工作面开采煤层顶板为中砂岩，厚度约44m ，抗拉强度为2．51MPa ，抗压强度为44．67MPa ，发育稳定。工作面从切眼向南推进50m 后，顶板出

支架拉移后伪现1层厚度约为500mm 的泥岩伪顶，

顶全部破碎为块状并落入采空区，造成压实机伸出后充填体在大块矸石的作用下与顶板形成大面积未

充实空间，随着工作面推进，顶板出现压力显现现象，局部出现直接顶板垮落1．5m ，严重影响工作面的充填效果。

为防止伪顶破碎后落入采空区，工作面机头至机尾全面铺设镀锌经纬网，拉架后利用经纬网包裹压实机伸出后充填体能够实现接顶，上覆破碎伪顶，保证了充填效果。

是实现矿井煤炭资源绿色开采的关取得初步成功，

键技术途径之一，不但能够解决建（构）筑物下压煤开采问题，还为处理矸石、粉煤灰等固体废弃物开辟了新的途径，具有深远的经济和社会意义。2）综合机械化固体充填采煤工艺，在用于传统综合机械化采煤工艺的类似地质采矿条件的同时，在煤层倾角、顶板稳定性方面又有其特殊的适用条件，根据实际揭露的地质条件，采取改变工作面推进方向及全面铺设金属网的优化措施，能够使采空区矸石充填率及压实率达到要求，保证充填效果。3）在工业性试验期间，要加强对充填采煤工艺的研究，建立地表移动观测站并进行定期观测，分析、总结地表变形规律，为充填开采技术的推广积累成功经验。

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［1］张吉雄，缪协兴，郭广礼．矸石（固体废物）直接充填采

J ］．采矿与安全工程学报，2009（4）：煤技术发展现状［395－401．

［2］瞿群迪，周华强，侯朝炯，等．煤矿膏体充填开采工艺的

J ］．煤炭科学技术，2004（10）：67－69，73．探讨［

［3］缪协兴，张吉雄，郭广礼．综合机械化固体充填采煤方法

J ］．煤炭学报，2010（1）：1－6．与技术研究［

［4］缪协兴，张吉雄，郭广礼．综合机械化固体废物充填采

M ］．徐州：中国矿业大学出版社，2010．煤方法与技术［

4结语

（责任编辑：李琴）

1）作为全国为数不多全部采用充填采煤工艺

的矿井，综合机械化固体充填采煤工艺在花园煤矿

檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭檭（上接第45页）

由30d 累计统计量计算得出的钻孔抽采半径大于利用拟合抽采衰减负指数曲线积分计算得出的钻孔抽采半径，这是因为在抽采过程中，煤层物理力学性质以及透气性系数均发生了变化，导致实际抽采量大于拟合计算积分量。3．5

71煤层预抽钻孔瓦斯抽采半径验证

试验考察的测压钻孔测得71煤层原始瓦斯压

抽采率进而确定钻孔不同抽采时间的抽采半径的方

简单易行，易于推广。法，

2）钻孔瓦斯抽采半径主要与煤层瓦斯含量、透气性系数、抽采钻孔直径及负压、抽采目的及时间等因素有关，当抽采条件发生改变时，矿井应重新确定抽采半径。

力为1．8～2．2MPa ，距抽采钻孔5m 位置布置的测压孔在抽采2个月后瓦斯压力降为1．4MPa ，表明抽采钻孔有效半径小于5m 。因此，在试验考察区域条件下71煤层预抽2个月的钻孔瓦斯抽采半径为3．7m ，符合实际情况。

参考文献：

［1］曹新奇，辛海会，徐立华，等．瓦斯抽放钻孔有效抽放半

J ］．煤炭工程，2009（9）：88－90．径的测定［

［2］范涛，王彦，樊中阳，等．崔庙煤矿二1煤层穿层钻孔抽放

J ］．煤炭技术，2008（4）：66－68．半径测定研究［

［3］于不凡，王佑安．煤矿瓦斯灾害防治及利用手册（修订

M ］．北京：煤炭工业出版社，2005．版）［

4结语

1）在已知煤层瓦斯含量基础上，选择一组抽采钻孔直接测定瓦斯抽采动态流量，按抽采目标确定·48·

（责任编辑：卫蓉）

Vol．39No．42012

MINING SAFETY &ENVIRONMENTAL PROTECTION

Aug. 2012

English Abstracts of This Issue

Numerical Simulation Study on Effect of Gas Concentration upon Gas Explosion (1)-Numerical simulation study on the explosion process of gas with concentration of 7.5%, 9.5%and 11.5%respectively in a square pipe was carried out by using the computational fluid dynamics (CFD)software Fluent, and analysis was made on the changes of pressure, temperature and the flame propagation speed in the explosion process. The results showed that the trend of flame propagation was roughly same in the explosion process of gas with three different concentrations, but the flame propagation speed, the pressure and temperature in the pipe were largely different. In addition, the flame propagation speed was faster than others and the pressure and temperature were the biggest in the explosion process of gas with concentration of 9.5%.The simulation results are consistent with the previous experimental ones.

Study on Height Development Characteristics of Two Zones of Overlying Strata in Deep Fully-mechanized Face in Huainan Coal Mining Area (5)-In this paper, study was made on the height of the caving zone and the water flowing fractured zone of overlying strata and their development characteristics by using the experience formula prediction, the numerical simulation and the site core quality index method in order to determine the development height of two zones of the overlying strata in the deep fully-mechanized coal face. The results showed that the development characteristics of two zones appeared to a "saddle" type after the coal was mined out and the maximum development height was located on the upper of the open-off cut of the face and the terminal line. The heights of two zones that were calculated with three different methods are respectively 42.29-45.77m, 57m and 53-55m. It is found through comparison that the numerical simulation result was more close to the site measured result, and the result obtained by experience formula prediction was small. The finally determined development height of the caving zone and water flowing fractured zone of the overlying strata is 55m.

Simulation Study on Failure Depth of No.1Seam Floor in Xinji No.2Mine (9)-The failure depth of No.1seam floor was simulated by using the numerical simulation software FLAC 3D on the basis of the analysis of the hydro-geological conditions of No.1seam in Xinjin M ine and the acquisition of the mechanical parameters. The results showed that the maximum failure depth of No.1seam floor was 19.17m; the maximum failure depth of the floor appeared at 30-40m place of the face advance, where the water inrush accident was most likely to occur. This research result can provide the scientific basis for the realization of safe mining of No.1seam in Xinji M ine, the design of water control and prevention scheme and the working out of water control and prevention measures for next working face.

Research on Mechanism of Water Inrush from Floor Subsided Column and Its Application (12)-The water-conducting subsided columns often bring larger hidden troubles to safe production in coal mines, so it is very necessary to analyze the mechanism of water inrush from subsided columns. In engineering practice, most of subsided columns are in irregular frustum form, in this study, the subsided column model was simplified as a frustum form so as to make it closer to the engineering practice, the M ohr-Coulomb strength criterion and the Limit Equilibrium theory were used to analyze the water inrush mechanism from the floor subsided columns, the limited water pressure of water inrush from the floor was solved, the water inrush from floor in a mine was predicted, and some preventive measures were put forward.

Test Research on Coal Measures Mudstone Permeability along Complete Stress-strain Path (18)-The permeability test in the complete stress-strain process was conducted in order to study the change characteristics of coal measures mudstone's permeability in the process of mining deformation. The test results showed that the increase of the permeability with the axial stress can be divided into three stages. On this basis, the pre-peak coupling analysis was conducted on the permeability and the complete stress process in consideration of their relatively complex features, the coupling regression equations of the permeability and the complete stress process were obtained, and investigation and study were made on the associated effect between the stress peak and the permeability peak. The results indicated that the mudstone's permeability did not reach the maximum value when most rock specimens' stress reached the peak value, and the permeability peak lagged behind the rock stress

peak. This test research revealed the change rule of coal measures mudstone's permeability under mining condition, and can provide a more important reference for the solution ofwater inrush in coal mines. Analysis on Occurrence Pattern of Complex Coal Seam Based on Surfer (24)-The occurrence of No. 5coal seam in 1930Coal M ine of Xinjiang Coking Coal (Group)Co., Ltd is not stable, and the traditional three point method has certain limitations to the determination of the occurrence pattern of the complex coal seam. In this paper, the authors conducted the study and analysis on the occurrence of the seam by using Suffer software, predicted the contours through the optimization with interpolation method and by using Kriging method and analyzed the occurrence of the seam by using polynomial regression method in order to accurately understand the occurrence pattern of coal seams. Study showed that there was a small regional structure change in No. 5coal seam; the basic occurrence was 264°∠22°; and the normal distance from the heading face of the inclined airshaft to the seam roof was 5.8m. This research result provided accurate references for exposing outburst seams in a crosscut at next stage. The use of Surfer software to analyse the occurrence pattern of complex coal seams is quick and intuitive.

Application of Borehole Imaging Method in Test of Broken Rock Zone of Roadway Surrounding Rock (31)-To exactly determine the size of the broken rock zone of roadway surrounding rock is of great significance for the selection of the reasonable support pattern and support parameters. At present, the test methods used for the broken rock zone of roadway surrounding rock have some disfigurements and deficiencies, so the borehole imaging method was studied in this paper. This method was used to test the size of the broken rock zone of the rail gangway in 3dow n 109coal face in Luxi M ine, the classification of roadway surrounding rock was determined, the support design was conducted, and good support effect was achieved. Finally, the range of the broken surrounding rock zone was simulated by using the computer numerical simulation method, the simulated results were identical to the results measured by borehole imaging method.

Determination Method for Gas Extraction Radius from Coal Seam by Boreholes and Practice (43)-The gas extraction radius by boreholes is mainly related to the factors such as the coal-seam gas content, the air permeability coefficient, the diameter and negative pressure of gas extraction borehole, the gas extraction

time and so on. A certain results can be obtained for the purpose ，

coal seam having better permeability and pressure measuring condition with the traditional determination method for gas extraction radius, but its efficiency is rather low; when the coal seam has poor permeability, the success rate of the measurement is extremely low and its applicability is poor. For this reason, direct measuring method was used for the measurement of dynamic gas extraction flow from boreholes on the basis of the coal-seam gas content being known, the extraction rate was determined according to the extraction purpose, and then the extraction radius by the borehole at different extraction time was also determined. The practice indicated that this method is practical and easy to generalize.

Methods and Models for Early Warning of Coal Mine Disaster Risk (85)-In order to timely and effectively send out early warning of the disaster risk in coal mines, a risk record system for coal mine disaster risk which is composed of “three violations ”, equipment troubles, abnormal environmental parameters, hidden dangers and accidents was constituted, and a combined index system for coal mine disaster risk which is suitable for the integration of multisource information and the dynamic change of production conditions in coal mines was established. By the combination of the control diagram with the columnar section, the time-space coordinate for the abnormal risk of coal mine disasters can be determined. In addition, a multi-model prediction method for disaster risk which was composed of regression model and GM(1,1)model was put forward, and an optimization tactics for two prediction models which was based on the small error probability -ratio of post-inspection differences and correlation coefficient -confidence probability was set up. According to the record system of 5types of risks and the analysis method for early warning of 3types of risks, an information flow model for the early warning of coal mine disaster risk was established, which can provide a certain guidance for the prevention and control of coal mine disasters.