Effect characteristics of air volume on gas enrichment in gob-side entry retaining working face with roof cutting

doi:10.16265/j.cnki.issn1003-3033.2026.07.0404

Abstract

Abstract:

To investigate the effect of Y-type ventilation in a gob-side entry retained by roof cutting on gas enrichment and distribution characteristics in a connected goaf, a high-gas mining face in the Huangling mining area was selected as the engineering background.. The overburden fracture distribution after goaf connection under gob-side entry retaining by roof cutting was simulated and analyzed using 3 Dimension Distinct Element Code(3DEC). A geometric model of the connected goaf was established. The effects of different air volumes under Y-type ventilation on gas enrichment zones in the connected goaf were investigated using Fluent. Based on the fracture characteristics, efficient gas extraction zones were determined. A directional long-borehole gas extraction scheme across the working face was designed. The results show that the caving zone on the roof-cutting side and the fracture zone on the non-cutting side of the 1009 goaf exhibit a high degree of fracture development. After the 1010 working faces is mined out, the two goafs are connected and form a connected goaf. The overburden subsidence further increases. When the air volume in No. 2 roadway is increased alone, the length of the low-gas zone along the strike of the goaf increases. The gas on the roof-cutting side along the dip direction is less disturbed. When the air-volume ratio between the main intake roadway and the auxiliary intake roadway is 2∶1, the length of the low-gas zone at different levels of the connected goaf increases 51.5-76.2 m with increasing air volume.During mining, the directional long boreholes across the working face enter a stable high-volume-fraction stage when they lag 178.3-190.5 m behind the working face. The average gas extraction volume fractions drilling sites are 52.6% and 48.3%, respectively. The overall gas extraction effect is good.

Key words: roof cutting and roadway retaining, connecting goaf, gas enrichment area, overburden fissures, Y-type ventilation method

CLC Number:

X936

Shuang Haiqing, Zhang Peizhen, Zhou Bin, Cui Mingwei, Xin Yueqiang, Chang Zhe. Effect characteristics of air volume on gas enrichment in gob-side entry retaining working face with roof cutting[J]. China Safety Science Journal, 2026, 36(7): 44-52.

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编号	岩性	厚度/m	关键层
17	中粒砂岩	30.3	—
16	粗粒砂岩	20.2	—
15	粉砂岩	13.2	—
14	砂质泥岩	33.8	—
13	细粒砂岩	12.5	主关键层
12	砂质泥岩	12	—
11	粉砂岩	8	亚关键层
10	砂质泥岩	14.5	—
9	1号煤	0.5	—
8	细粒砂岩	2	—
7	砂质泥岩	4	—
6	细粒砂岩	4	亚关键层
5	砂质泥岩	10	—
4	2号煤	2.5	—
3	泥岩	2.5	—
2	砂质泥岩	2.5	—
1	细粒砂岩	4.5	—