Haitao Wang^1,2, Yongli Liu^1,*, Bin Shen¹, Mengxuan Ren¹, Qiyuan Shan¹

Energy Engineering, Vol.119, No.5, pp. 2031-2047, 2022, DOI:10.32604/ee.2022.020776

Abstract The goal of this study was to investigate coal quality features and their relationship to coal spontaneous combustion characteristics in multi-seam coal mines to better predict when coal spontaneous combustion is likely to occur. To that end, coal samples of various particle sizes were obtained from five coal seams (Nos. 6, 8, 9, 12 and 20) in the Shuangyashan City Xin’an Coal Mine. The samples were then respectively heated using a temperature programming system to observe and compare similarities and differences in the spontaneous combustion process of different particle sizes in response to rising temperature. The experimental results show, that… More >

Xiyuan Li¹, Peng Chu^2,3,*, Zhuang Lu^2,3, Yuanyuan Liu^2,3, Zibin Zhu^2,3, Jin Gao^2,3, Xiaoxue Liao^2,3, Tao Yang^2,3

Energy Engineering, Vol.118, No.6, pp. 1811-1825, 2021, DOI:10.32604/EE.2021.015751

Abstract The permeability is a key factor to determine the efficiency of coalbed methane (CBM) production. The borehole enlargement technology using hydraulic and mechanical measures to cut coal is an effective method to increase the coal seam permeability and improve the efficiency of gas drainage. Reasonable design of the layout of boreholes is the prerequisite for efficient and economical gas drainage. In this paper, based on the strain-softening model, the stress and permeability model of the coal seam around the enlarged borehole was built, and based on the dual-medium model, the gas migration model in the coal seam was established. Then… More >

Chunlei Zhang^1,2,3,*, Y. P. Chugh², Ruimin Feng⁴, Yong Zhang⁵, Wei Shen¹, Jingke Wu¹, Yushun Yang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.1, pp. 135-157, 2021, DOI:10.32604/cmes.2021.014665

Abstract Extraction of a protective coal seam (PVCS)-below or above a coal seam to be mined with the potential of coal and gas outburst risk-plays an important role not only in decreasing the stress field in the surrounding rock mass but also in increasing the gas desorption capacity and gas flow permeability in the protected coal seam (PTCS). The PVCS is mined to guarantee the safe mining of the PTCS. This study has numerically evaluated the stress redistribution effects using FLAC3D model for a longwall face in Shanxi Province. The effects of mining depth, mining height and inter-burden rock mass properties… More >

Zhibin Lin¹, Boyang Zhang^1,2,*, Jiaqi Guo¹

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 311-330, 2021, DOI:10.32604/cmes.2021.011556

Abstract Minin-induced water inrush from a confined aquifer due to subsided floor karst collapse column (SKCC) is a type of serious disaster in the underground coal extraction. Karst collapse column (KCC) developed in a confined aquifer occurs widely throughout northern China. A water inrush disaster from SKCC occurred in Taoyuan coal mine on February 3, 2013. In order to analyze the effect of the KCC influence zone’s (KCCIZ) width and the entry driving distance of the water inrush through the fractured channels of the SKCC, the stress, seepage, and impact dynamics coupling equations were used to model the seepage rule, and… More >

JiangtaoLi^1,2,*

Intelligent Automation & Soft Computing, Vol.26, No.5, pp. 1047-1061, 2020, DOI:10.32604/iasc.2020.010136

Abstract In view of poor permeability of coal seam and soft coal quality in China's coal mining area, a point hydraulic fracturing method suitable for the occurrence characteristics of coal seam is put forward based on the characteristics of coal seam hydraulic fracturing and the field practical experience of coal seam hydraulic fracturing for many years. A theoretical and mathematical model of hydraulic fracturing is established. Based on the large-scale finite element software ABAQUS, numerical simulation of two dimensional and three dimensional hydraulic fracturing is carried out, and the fracture propagation law and its parameter sensitivity of coal seam point hydraulic… More >

Dengfeng Su¹, Yong Kang^1,2,*, Xiaochuan Wang², andan Zheng¹, DongyangLi¹, Binyuan Yan¹, Fuwen Yan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.5, pp. 375-393, 2016, DOI:10.3970/cmes.2016.111.375

Abstract Tunnel though coal seam is one of the most difficult tunnels since its risk of coal and gas outburst and the complex geological conditions. According to the directional cutting of water jet and the characteristic of the coal seam and rock mass, this paper presents a new method of tunnelling though coal seam assisted by water jet slotting, which can be divided into improving permeability of coal seam and directional cracking in the rock mass. The mechanism of improving permeability of coal seam was stated, and the crack criterion of rock during blasting was established based on fracture theory. Then,… More >

Xuebo Zhang^{1, 2, 3}, Zhiwei Jia^{1, 2, 3, *}

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.1, pp. 53-61, 2019, DOI:10.32604/fdmp.2019.04779

Abstract The influence of ground stress was quantitatively analyzed on coal seam gas pressure and gas content in this paper. Mining activities in coal mine can result in stress concentration in the coal (rock) body around the mining space, but porosity of the coal seam would not change too much. Therefore, gas pressure and gas content in the coal seam are slightly affected. Studies showed that the free gas was gradually transformed into adsorbed gas, and the gas adsorption volume was small, and then gas pressure increases roughly linearly when the porosity decreased because of stress influence. Additionaly, when porosity of… More >

Yi Xue^1,2, Feng Gao^1,2,3, Xingguang Liu⁴, Xiru Li²

CMC-Computers, Materials & Continua, Vol.47, No.2, pp. 127-141, 2015, DOI:10.3970/cmc.2015.047.127

Abstract In order to study the effect of high pressure water jet cutting technology on the permeability of single coal seam, we use the damage variable to describe the fracture distribution of coal seam, develop the 3-D finite element program based on the damage theory, and then analyze the damage distribution of coal seam after drilling and slotting. Using MTS815 rock mechanics testing system and the permeability test system, we conduct the permeability test and get the relationship between permeability and damage. Based on the damage distribution of coal seam after drilling and slotting and the permeability change law, we analyze… More >