Research On Stability Control And Supporting Technology Of Roadway Driving In The Residual Coal Remining Of Old Mining

In recent years,China's coal industry has made considerable development,and per unit area yield of the advanced mine's mining working face has been in the leading level of the world.But China's coal enterprises generally have the phenomenon of "mining the easy job and discarding the difficulty",especially only mining the solid coal of large area occurrence and discarding the residual coal resources of the large area destruction through the backward and old mining methods-called "old mining" for short,such as room-and-pillar mining method,roadway-and-pillar mining method,and so on..Taking Jincheng city Shanxi province as an example,the No.3 coal seam of buried at the shallow depth of the earth and known as "orchid carbon" had been generally mined by the old method before the 90 time metaphase in this area.Restricted by the mining method and the mechanization level at that time,resource recovery rate is less than 30%so that a large number of high-quality coal resources had been destroyed.With the increasing of mining intensity and lower coal group have been mining in recent years,many of the coal mine enterprises face a serious problem of resource depletion and further damage to the residual coal resource.Therefore,it is a great realistic significance to remine the coal resource destroyed by the old mining.Residual coal remining is different from the coal mining under the conditions of the original rock stress field.Due to the influence of the old mining,old mining area's of the properties of surrounding rock,stress characteristics,occurrence of coal seam,space distribution has the very big difference from the coal mining not affected by mining rock in the original rock stress area.Thereby,how to safely and efficiently recycle the coal resources in old mining area has become an urgent technical problem.Nevertheless,stability control and supporting technology of remining roadway driving is the first problem to be solved urgently.Based on previous research and around the subject of stability control and supporting technology of remining roadway driving,the paper analyzes systematically the occurrence characteristics of coal seam in the old mining area,the deformation characteristics of residual coal pillar by the means of the theoretical analysis,the numerical simulation,the site investigation and the engineering analogy method or other means.The article discusses and studies the No.3 coal occurrence of the Yin Jia Gou mine,and put forward to control the basic theory and key technology of the remining roadway surrounding rock.The following aspects are the main work.1?Based on the analysis of the damage zone division and its characteristics of overlying strata,the roof caving characteristics,lithology of roof and floor,fissured zone and other overlying strata failure law of the old mining,the article obtains coal seam's 5 kinds of column distribution characteristics and 7 kinds of space distributions in the old mining area,and comes to conclusion that the vertical stress influence degree and scope is larger than the horizontal stress under the conditions of the coal pillar regional stress field by the means of FLAC3D numerical simulation software calculation.2?According to the theory of loosened rock circles around the tunnel and through the analysis of the remining roadway's surrounding rock type,the regenerated roof classification and the surrounding rock property,the paper comes to the conclusion that the remining roadway's surrounding rock have the geological soft rock's characteristics of "loose,scattered,soft,weak",and have the properties of engineering soft rock,such as the larger in surrounding rock deformation,the higher in the stress concentration factor of the remining roadway's surrounding rock in the coal pillar,and the larger in plastic deformation in the process of tunnel excavation,etc.The remining roadway's surrounding rock presents the typical characteristics of the broken soft rock of the big loosen rock zone,and should place in the surrounding rock of the big loosen rock zone.3?The article analyzes the deformation characteristics of surrounding rock of remining roadway,and uses FLAC3D numerical simulation software to study characteristics of the surrounding rock stress distribution when the remining surrounding rock is in the coal pillar,the old mining caving zone and intersecting with the empty tunnel.combined with the pressure characteristics,the control principle and the surrounding rock supporting object in the remining roadway surrounding rock,the paper put forward the basic theory of the remining roadway surrounding rock control:(1)to reduce the disturbance of the remining roadway surrounding rock;(2)to depend on the rigid support as the main support scheme;(3)to use the flexibly the pressure control theory of surrounding rock;(4)to strengthen the consolidation for the key parts.4?The paper puts forward the key control technologies of the surrounding rock in the remining roadway under the guidance of the control theory of the remining roadway surrounding rock:(1)the advanced supporting technology of the drill rob wedging method;(2)the supporting technology of the i-steel shed frame;(3)the bolt-grouting reinforcement technology of the surrounding rock;(4)the supporting technology of the prestressed truss bolt.5?the article puts forward the supporting technology schemes of the remining roadway,and uses FLAC3D and UDEC numerical simulation software to optimize the supporting parameters to obtain the best scheme.