Ground response to high horizontal stresses during longwall retreat and its implications for longwall headgate support
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摘要
Roof falls in longwall headgate can occur when weak roof and high horizontal stress are present. To prevent roof falls in the headgate under high horizontal stress, it is important to understand the ground response to high horizontal stress in the longwall headgate and the requirements for supplemental roof support. In this study, a longwall headgate under high horizontal stress was instrumented to monitor stress change in the pillars, deformations in the roof, and load in the cable bolts. The conditions in the headgate were monitored for about six months as the longwall face passed by the instrumented site.The roof behavior in the headgate near the face was carefully observed during longwall retreat.Numerical modeling was performed to correlate the modeling results with underground observation and instrumentation data and to quantify the effect of high horizontal stress on roof stability in the longwall headgate. This paper discusses roof support requirements in the longwall headgate under high horizontal stress in regard to the pattern of supplemental cable bolts and the critical locations where additional supplemental support is necessary.
Roof falls in longwall headgate can occur when weak roof and high horizontal stress are present. To prevent roof falls in the headgate under high horizontal stress, it is important to understand the ground response to high horizontal stress in the longwall headgate and the requirements for supplemental roof support. In this study, a longwall headgate under high horizontal stress was instrumented to monitor stress change in the pillars, deformations in the roof, and load in the cable bolts. The conditions in the headgate were monitored for about six months as the longwall face passed by the instrumented site.The roof behavior in the headgate near the face was carefully observed during longwall retreat.Numerical modeling was performed to correlate the modeling results with underground observation and instrumentation data and to quantify the effect of high horizontal stress on roof stability in the longwall headgate. This paper discusses roof support requirements in the longwall headgate under high horizontal stress in regard to the pattern of supplemental cable bolts and the critical locations where additional supplemental support is necessary.
Roof falls in longwall headgate can occur when weak roof and high horizontal stress are present. To prevent roof falls in the headgate under high horizontal stress, it is important to understand the ground response to high horizontal stress in the longwall headgate and the requirements for supplemental roof support. In this study, a longwall headgate under high horizontal stress was instrumented to monitor stress change in the pillars, deformations in the roof, and load in the cable bolts. The conditions in the headgate were monitored for about six months as the longwall face passed by the instrumented site.The roof behavior in the headgate near the face was carefully observed during longwall retreat.Numerical modeling was performed to correlate the modeling results with underground observation and instrumentation data and to quantify the effect of high horizontal stress on roof stability in the longwall headgate. This paper discusses roof support requirements in the longwall headgate under high horizontal stress in regard to the pattern of supplemental cable bolts and the critical locations where additional supplemental support is necessary.
引文
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[2]Chen JS,Mishra M,Dubois G,Demichiei John.Effects of panel mining sequence and retreat direction on the roof stability of longwall headgate entries.In:Proceedings of the 17th international conference on ground control in mining.Morgantown(WV):West Virginia University;1998.p.95-101.
[3]Su DWH,Hasenfus GJ.Regional horizontal stress and its effect on longwall mining in the Northern Appalachian coal field.In:Proceedings of the 14th international conference on ground control in mining.Morgantown(WV):West Virginia University;1995.p.39-45.
[4]Su DWH,Thomas EP,Hasenfus GJ.Roof geology mapping in underground coal mines.In:Proceedings of the 18th international conference on ground control in mining.Morgantown(WV):West Virginia University;1999.p.40-9.
[5]Su DWH,Morris TJ,McCaffrey J.Influence of structural stress concentration and structural irregularity on longwall gateroad roof control.In:Proceedings of the 21st international conference on ground control in mining.Morgantown(WV):West Virginia University;2002.p.18-26.
[6]Su DWH,Draskovich DJ,Thomas EP.Pillar design and roof support for controlling longwall headgate subject to high horizontal stresses.In:Proceedings of the 22nd international conference on ground control in mining.Morgantown(WV):West Virginia University;2003.p.1-10.
[7]Hasenfus GJ,Su DWH.Horizontal stress and coal mines:twenty-five years of experience and perspective.In:Proceedings of the 25th international conference on ground control in mining.Morgantown(WV):West Virginia University;2006.p.256-67.
[8]Lu J,Mark Van Dyke,Su Daniel WH,Greg Hasenfus.Transitional geology and its effects on development and longwall mining in Pittsburgh Seam.Int JMining Sci Technol 2016;26(1):31-7.
[9]Gearhart D,Zhang P,Esterhuizen GS.Analysis of the effects of a passing longwall face on the roadway,pillars and standing supports.In:Proceedings of the 37th international conference on ground control in mining.Morgantown(WV):West Virginia University;2018.p.359-65.
[10]Tulu IB,Esterhuizen GS,Mohamed KM,Klemetti TM.Verification of a calibrated longwall model with field measurements.In:Proceedings of the51st US rock mechanics/geomechanics symposium.San Francisco(California):American Rock Mechanics Association;2017.p.8.
[11]Esterhuizen GS,Gearhart DF,Tulu B.Analysis of global and local stress changes in a longwall gateroad.Int J Mining Sci Technol 2018;28(1):127-35.
[12]Esterhuizen GS,Mark C,Murphy MM.Numerical model calibration for simulating coal pillars,gob and overburden response.In:Proceedings of the29th international conference on ground control in mining.Morgantown(WV):West Virginia University;2010.p.46-57.
[13]Itasca.FLAC3DTM.Minneapolis(MN):Itasca Consulting Group,Inc.;2017.
[14]West Virginia University.CISPM-W.Morgantown(WV):West Virginia University;2009.
[15]Puller JW,Mills Ken W,Jeffrey rob G,Walker Rick GJ.In-situ stress measurements and stress change monitoring to monitor overburden caving behavior and hydraulic fracture pre-conditioning.Int J Mining Sci Technol2016;26(1):103-10.
[2]Chen JS,Mishra M,Dubois G,Demichiei John.Effects of panel mining sequence and retreat direction on the roof stability of longwall headgate entries.In:Proceedings of the 17th international conference on ground control in mining.Morgantown(WV):West Virginia University;1998.p.95-101.
[3]Su DWH,Hasenfus GJ.Regional horizontal stress and its effect on longwall mining in the Northern Appalachian coal field.In:Proceedings of the 14th international conference on ground control in mining.Morgantown(WV):West Virginia University;1995.p.39-45.
[4]Su DWH,Thomas EP,Hasenfus GJ.Roof geology mapping in underground coal mines.In:Proceedings of the 18th international conference on ground control in mining.Morgantown(WV):West Virginia University;1999.p.40-9.
[5]Su DWH,Morris TJ,McCaffrey J.Influence of structural stress concentration and structural irregularity on longwall gateroad roof control.In:Proceedings of the 21st international conference on ground control in mining.Morgantown(WV):West Virginia University;2002.p.18-26.
[6]Su DWH,Draskovich DJ,Thomas EP.Pillar design and roof support for controlling longwall headgate subject to high horizontal stresses.In:Proceedings of the 22nd international conference on ground control in mining.Morgantown(WV):West Virginia University;2003.p.1-10.
[7]Hasenfus GJ,Su DWH.Horizontal stress and coal mines:twenty-five years of experience and perspective.In:Proceedings of the 25th international conference on ground control in mining.Morgantown(WV):West Virginia University;2006.p.256-67.
[8]Lu J,Mark Van Dyke,Su Daniel WH,Greg Hasenfus.Transitional geology and its effects on development and longwall mining in Pittsburgh Seam.Int JMining Sci Technol 2016;26(1):31-7.
[9]Gearhart D,Zhang P,Esterhuizen GS.Analysis of the effects of a passing longwall face on the roadway,pillars and standing supports.In:Proceedings of the 37th international conference on ground control in mining.Morgantown(WV):West Virginia University;2018.p.359-65.
[10]Tulu IB,Esterhuizen GS,Mohamed KM,Klemetti TM.Verification of a calibrated longwall model with field measurements.In:Proceedings of the51st US rock mechanics/geomechanics symposium.San Francisco(California):American Rock Mechanics Association;2017.p.8.
[11]Esterhuizen GS,Gearhart DF,Tulu B.Analysis of global and local stress changes in a longwall gateroad.Int J Mining Sci Technol 2018;28(1):127-35.
[12]Esterhuizen GS,Mark C,Murphy MM.Numerical model calibration for simulating coal pillars,gob and overburden response.In:Proceedings of the29th international conference on ground control in mining.Morgantown(WV):West Virginia University;2010.p.46-57.
[13]Itasca.FLAC3DTM.Minneapolis(MN):Itasca Consulting Group,Inc.;2017.
[14]West Virginia University.CISPM-W.Morgantown(WV):West Virginia University;2009.
[15]Puller JW,Mills Ken W,Jeffrey rob G,Walker Rick GJ.In-situ stress measurements and stress change monitoring to monitor overburden caving behavior and hydraulic fracture pre-conditioning.Int J Mining Sci Technol2016;26(1):103-10.