Research on dynamic change characteristics of three-dimensional spontaneous combustion zone in caving coal face

doi:10.16265/j.cnki.issn1003-3033.2022.03.009

Abstract

Abstract:

In order to explore dynamic distribution characteristics of spontaneous combustion zone in goaf, a combination of theoretical analysis, numerical simulation and field measurement were used to study effects of changes in voids, fracture structure and oxidation rate on features of air leakage and oxygen volume fraction distribution, and it was revealed that spontaneous combustion zone of fully mechanized top coal caving changed from the back of goaf to top coal in working face. The results show that the fracture of top coal and void structure of mined-out area change with extension of exposure time due to influence of mining stress and overburden caving lag. Free diffusion air leakage is formed in open field of upper and middle eaves behind the support, and as exposure time of caving coal and rock mass increase, oxygen consumption rate increases, top coal fracture structure develops, caving space in goaf moves up, and internal void structure in middle and lower part declines, leading to the expansion of spontaneous combustion zone from the back of goaf to top coal of fully mechanized mining support.

Key words: fully mechanized top coal caving, three-dimensional spontaneous combustion zone, coal crack, oxygen consumption rate, dynamic change characteristics

ZHAO Wenbin, LIU Fangshun, SHI Xinyan, LIU Hui, WANG Zhongmi, LI Zhenwu. Research on dynamic change characteristics of three-dimensional spontaneous combustion zone in caving coal face[J]. China Safety Science Journal, 2022, 32(3): 65-74.

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模块名称	数值	模块名称	数值
采空区深度×长×高/(m×m×m)	20×120×9	岩体碎胀系数	1.2
工作面长×宽×高/(m×m×m)	120×5×3.5	氧气体积分数的衰减率/(mol·s^-1)	3.169×10^-5
进回风巷长×宽×高/(m×m×m)	5×5×3.5	下限氧体积分数	0.002 3
工作面倾角/(°)	0	反应指前因子	60
直接顶高度/m	6	煤的活化能/(kJ·mol^-1·K^-1)	100
采高/煤厚,m	3.5/9	氧气体积分数/%	21
垮落岩石容重/(N·m^-3)	2×10⁴~3×10⁴	进回风口压差/Pa	50