The wide pillars are generally popular due to the high productivity and efficiency in Northwest China.The distribution of lateral abutment pressure in coal pillars is important for mining safety.To reveal the effect o...The wide pillars are generally popular due to the high productivity and efficiency in Northwest China.The distribution of lateral abutment pressure in coal pillars is important for mining safety.To reveal the effect of the first mining on the lateral abutment pressure distribution and evolution in wide pillars,an in-situ experiment,theoretical analysis and numerical simulation were performed.First,the field monitoring of lateral abutment pressure was conducted from the perspective of time and space in the Chahasu Coal Mine,Huangling No.2 Coal Mine and Lingdong Coal Mine during the first mining.Based on the field monitoring stress,a theoretical model was proposed to reveal the lateral abutment pressure distribution.The methodology was demonstrated through a case study.Aiming at the distribution mechanism,a numerical experiment was conducted through the finite-discrete element method(FDEM).Last,field observations of borehole fractures were performed to further study the damage distribution.In addition,two types of lateral abutment pressure evolution with mining advance were discussed.Suggestions on the stress monitoring layout were proposed as well.The results could provide foundations for strata control and disaster prevention in wide pillars in underground coal mines.展开更多
This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village ho...This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village houses. The stratum structure control action of mining subsidence was used to design the mining and pillar width. To further raise resources recovery, we adopted the mutative scheme of mining and pillar width. Observation was carried out while mining. Research shows there is feasibility of the strip mining technology to protecting the village buildings of the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. Finally, subsidence parameters of strip mining were obtained. It is the basic data of the strip mining of the coal field at the north of the Yellow River.展开更多
In order to solve the difficult conditions of soft rock,water-trickling and hard-maintain of main air-return roadway in Tarangaole Colliery,high pretensioned stress and intensive bolt-shotcrete support program was des...In order to solve the difficult conditions of soft rock,water-trickling and hard-maintain of main air-return roadway in Tarangaole Colliery,high pretensioned stress and intensive bolt-shotcrete support program was designed and mechanical property of shotcrete layer was specially monitored through utilizing a type of concrete stress meter with oscillating chord after the program was carried out.It was indicated that,due to rock pressure and support resistance,the interior of shotcrete layer would emerge diverse stresses in axial,radial and tangential directions.With time passing internal stresses in three directions,whose average values were-0.061,0.043 and 0.517 MPa respectively,fluctuated first and then tended to stability slowly.The axial and radial stresses were relatively smaller than tangential stress which was 11,12 times the two formers respectively.Along the section of roadway,axial and tangential stresses distributed symmetrically and increased gradually from the top of arch to the waist of wall,but reduced at the foot of wall.Radial stresses reduced from the top of arch to the waist of arch first,and then increased in the waist of wall.Axial stresses were tensile substantially,except for stresses in arch vault tending to compressive,but all the radial stresses were compressive.Nevertheless,tangential stresses in the wall were compressive and tangential stresses in the arch were tensile.During the period of roadway excavating,the stress of shotcrete layer was less than its ultimate bearing capacity,with no significant stress concentration.At the end of this article,some suggests are given to shotcrete support design.展开更多
基金We gratefully acknowledge financial support from the National Natural Science Foundation of China(NSFC)(No.51704097)Science Foundation of Henan Polytechnic University(No.J2021–2)+1 种基金Key Research and Development Program of Henan Province,China(No.202102310244)“Science and Technology to Help the Economy 2020”Key Project(No.SQ2020YFF0426364).
文摘The wide pillars are generally popular due to the high productivity and efficiency in Northwest China.The distribution of lateral abutment pressure in coal pillars is important for mining safety.To reveal the effect of the first mining on the lateral abutment pressure distribution and evolution in wide pillars,an in-situ experiment,theoretical analysis and numerical simulation were performed.First,the field monitoring of lateral abutment pressure was conducted from the perspective of time and space in the Chahasu Coal Mine,Huangling No.2 Coal Mine and Lingdong Coal Mine during the first mining.Based on the field monitoring stress,a theoretical model was proposed to reveal the lateral abutment pressure distribution.The methodology was demonstrated through a case study.Aiming at the distribution mechanism,a numerical experiment was conducted through the finite-discrete element method(FDEM).Last,field observations of borehole fractures were performed to further study the damage distribution.In addition,two types of lateral abutment pressure evolution with mining advance were discussed.Suggestions on the stress monitoring layout were proposed as well.The results could provide foundations for strata control and disaster prevention in wide pillars in underground coal mines.
文摘This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village houses. The stratum structure control action of mining subsidence was used to design the mining and pillar width. To further raise resources recovery, we adopted the mutative scheme of mining and pillar width. Observation was carried out while mining. Research shows there is feasibility of the strip mining technology to protecting the village buildings of the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. Finally, subsidence parameters of strip mining were obtained. It is the basic data of the strip mining of the coal field at the north of the Yellow River.
文摘In order to solve the difficult conditions of soft rock,water-trickling and hard-maintain of main air-return roadway in Tarangaole Colliery,high pretensioned stress and intensive bolt-shotcrete support program was designed and mechanical property of shotcrete layer was specially monitored through utilizing a type of concrete stress meter with oscillating chord after the program was carried out.It was indicated that,due to rock pressure and support resistance,the interior of shotcrete layer would emerge diverse stresses in axial,radial and tangential directions.With time passing internal stresses in three directions,whose average values were-0.061,0.043 and 0.517 MPa respectively,fluctuated first and then tended to stability slowly.The axial and radial stresses were relatively smaller than tangential stress which was 11,12 times the two formers respectively.Along the section of roadway,axial and tangential stresses distributed symmetrically and increased gradually from the top of arch to the waist of wall,but reduced at the foot of wall.Radial stresses reduced from the top of arch to the waist of arch first,and then increased in the waist of wall.Axial stresses were tensile substantially,except for stresses in arch vault tending to compressive,but all the radial stresses were compressive.Nevertheless,tangential stresses in the wall were compressive and tangential stresses in the arch were tensile.During the period of roadway excavating,the stress of shotcrete layer was less than its ultimate bearing capacity,with no significant stress concentration.At the end of this article,some suggests are given to shotcrete support design.
