doi:10.16186/j.cnki.1673-9787.2020.2.1

Received:2019/05/09

Revised:2019/06/18

Published:2020/03/15

Analysis of mine pressure behavior characteristics in the period of gateway exca-vation of variable width coal pillar in fully mechanized caving face in extra-thickcoal seam

CHEN Xiangqi, LI Huamin, WANG Shen, WANG Zuguang

School of Energy Science and Engineering， Henan Polytechnic University ，Jiaozuo 454000 ， Henan， China

Abstract:In order to study the deformation and failure characteristics of surrounding rock in fully mechanized caving face with variable width coal pillar during gateway excavation in extra-thick coal seam of Tashan coal mine， Datong Coal MIne Group Co. Ltd. ， the field measurement， numerical calculation and theoretical analysis method were used to analyze the law of mine pressure behaviors of surrounding rock during gateway excavation in variable width coal pillar. The surrounding rock stress field and the energy distribution characteristics of coal-rock mass under the condition of widening coal pillar retaining roadway were studied， and the mechanism of mine pressure behaviors during the gateway excavation of variable width coal pillar in extra-thick coal seam was obtained. The research showed that there were strong rock pressure phenomena such as sound， vibration， roof fall and rib spalling during roadway excavation with variable width pillar in extra-thick coal seam. It mainly occured in the period of coal breaking and driving within the range of coal pillar width from 22.4 m to 47.9 m. The lateral stress and the coal body energy were concentrated in the range of the edge of the goaf from 30 mto 40 m ， and were distributed in a belt shape. With the width of the coal pillar increased， the surrounding rock side of the gateway increased. The energy curves of stress and surrounding rock showed a trend of first increasing and then decreasing. When the width of the coal pillar was about 35 m， the lateral stress and the coal body energy reached the maximum of 24. 27 MPa and 7. 29 × 10⁵ J， respectively. The equilibrium state of mechanics of beam structure was destroyed， which caused rapid dynamic adjustment of surrounding rock stress. When the static load in the coal-rock mass was superimposed on the dynamic load caused by the mining activity and exceeded the bearing limit of the coal-rock mass， a large amount of elastic strain energy accumulated in the coal body was released in the form of kinetic energy， thus the mine pressure behaviors of gateway appeared.

Key words:extra-thick coal seam;fully mechanized caving face;variable width coal pillar;excavation gateway;mine pressure behavior characteristic

特厚煤层综放工作面变宽煤柱段巷道掘进期间围岩矿压显现特征分析_陈祥祺.pdf