Numerical simulation research on dynamical variation of permeability of coal around roadway based on gas-solid coupling model for gassy
rmscoal
Tao Yang a,b,c,d,⇑,Bo Li c,d ,Qiusheng Ye a
a
School of Safety Science and Engineering,North China Institute of Science and Technology,Beijing 101601,China b
State Key Laboratory of Coal Resources and Safe Mining (China University of Mining and Technology),China c
School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China d
Hebei State Key Laboratory of Mine Disaster Prevention,North China Institute of Science and Technology,Beijing 101601,China
a r t i c l e i n f o Article history:
Received 3July 2018
Received in revised form 13September 2018
Accepted 22September 2018
Available online 28September 2018Keywords:
Coupled model Permeability Roadway
Numerical simulation Gassy coal
湖南御邦大宗农产品交易所
a b s t r a c t Due to the change of initial stress state caused by roadway excavation,the permeability of the coal body may be changed during the excavation process.In this paper,according to the different stress states,the coal around the roadway was divided into the seepage open zone,seepage orientation zone,seepage decay zone and original seepage zone along the radial direction of the roadway.The l
oaded gassy coal was treated as a viscoelastic and plastic softened medium,and the mechanical behaviors of the viscoelas-tic zone,plastic softened zone and broken zone around the roadway were analyzed with the considera-tion of the loading creep,softening and expansion effect of the gassy coal.According to the law of conservation of mass and the Darcy law,the flow-solid coupled model for the gas transportation of the coal around the roadway was established considering the dynamic evolution of the adsorption character-istics,porosity and permeability of the coal,and the simulation software COMSOL was utilized to numer-ically simulate the stress state and gas flow regularity around the coal,which provided meaningful reference for investigating the stability of the coal and rock around the roadway.
Ó2018Published by Elsevier behalf of China University of Mining &Technology.This is an open
access article under the CC BY-NC-ND license (/licenses/by-nc-nd/4.0/).
1.Introduction
During roadway excavation,the stress state of the coal around the roadway may be changed,and the permeability of the coal will change dramatically in the process.Stress filed and seepage field are tw
o main components in the mechanical environment of the coal around the roadway,and they influence and interact with each other.Since the stress change of the coal around the roadway during excavation is a dynamic process,the stresses at different positions around the roadway are different,which results in differ-ent deformation characteristics as well as remarkable difference of the stress state.Therefore,deep investigation on the evolution and the space distribution feature of stress and permeability during and after roadway excavation is of great significance for analyzing the control mechanism of coal and rock stability around the roadway.
The coal gas flow-solid coupling theory was a new mechanics branch from the interaction of hydromechanics and solid mechan-ics.In 1923,Terzaghi firstly took the coupled issue of fluid flow and porous medium deformation as research objective and proposed famous effective stress formula.Based on some ideal assumptions,the single-dimensional consolidation model was established,but it is only widely applied in the soil mechanics [1].Although the one-dimensional model was promoted to three-dimensional space in 1943,this model had no basic difference compared with the orig-inal one-dimensional solidification theory because the total stress in the solidification process was still assumed as a constant.Research by Terzaghi et al.established the three-dimensional solidification theory with total stress of saturated soil body and pore-fluid pressure
as state variables [2].The anisotropic consoli-dation theory for pore solid is followed,which provides a founda-tion for the study of the Flow-Solid coupled theory [3–6].Lubinski and Geertsma discussed the Biot equation in their study on the pore elastic theory for porous medium respectively [7,8].Svagae further applied the three-dimensional consolidation theory sug-gested by Biot to porous and elastic medium with the transverse isotropy [9].Ziekniewicz considered the geometric and material non-linear characteristic,and proposed a generalized Biot Formula based on the three-dimensional consolidation theory [10].Vemitij developed a theoretical model for the coupled effect of multiphase saturated flow and porous medium,and established a theoretical model for the coupled issue of Euler-type multiphase fluid move-
/10.1016/j.ijmst.2018.09.004
2095-2686/Ó2018Published by Elsevier behalf of China University of Mining &Technology.
This is an open access article under the CC BY-NC-ND license (/licenses/by-nc-nd/4.0/).
深圳住房公积金
管理条例⇑Corresponding author at:467#Xueyuan Road,East Yanjiao,Beijing 101601, 李倩蕾E-mail address:yangtao585@163 (T.Yang).
International Journal of Mining Science and Technology 28(2018)
925–932
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International Journal of Mining Science and Technology
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