Research On Stability Control Of The Cave Roof Surrounding Rock With Ooze Invaded

Under the influence of coal seam occurrence conditions, the caveroof which is rich of ooze invaded are distributed in many mining areas,stability control of the roadway of roof is a technical problem which isneed to be solved urgently. This paper selects Yongju coal industry10#Karst cave roof roadway as the engineering background, combined withhe karst cave Grouting theory, analysis and research the stability controlmechanism of cave roof roadway surrounding rock. Using Karst caveGrouting similar simulation, failure test of pressure Grouting in rockmass and numerical simulation method, search the reasonable groutingmaterial, parameters and support ways of roadway. Through practicalapplication and in-site monitoring that achieved good results.Results aremainly the following points:（1）The cave roof which is rich of ooze, effect of holes, the in situmechanical properties is low strength（uniaxial compressive strength ofabout10.7～18.9MPa） and poor self-stability, under the action of highstress, roadway roof could easily collapse and caving, stabilitymaintenance of cave roof roadway surrounding rock is extremelydifficult. （2）For the cave roof characteristics which is rich of ooze invaded,combined in suit modified theory of grouting in surrounding rock, putforward the reinforcement technology which use cave roof piecewiseplugging and zoning grouting, after routing in surrounding rock, integrityof the roof rock is improved, bearing capacity of the roof supportstructure is improved. Analysis shows that grouting material andparameter, reasonable choice of supporting mode can directly affect thestability control of the cave roof roadway surrounding rock.（3）For the actualengineering conditions of cave roof characteristicswhich is rich of ooze invaded, using similar simulation of grouting,numerical simulation and the test of mechanical property ect method todo the comprehensive analysis, confirm that the ratio of optimal waterand mud for cave roof grouting is0.8:1, the amount of water glass is25%as the volume of the cement. The optimal supporting mode forroadway roof is arched section+anchor (cable)+29Usteel+steel fiberconcrete joint supporting.（4）Analysis showed that: after using grouting for the cave roofwhich is rich of ooze(ratio of water and mud is0.8:1), it can promotestrength of the roadway surrounding rock about37.9%～165%,deformation amount of the surrounding rock of roadway roof and floorreduce66.16%～93.79%, it is benifit to self stability, compressivestrength and the effect of grouting; numerical simulation research showedthat, the influence of karst cave on the tunnel roof ooze above theroadway roof is limited, the effects range is3～4times of the roadwaysize, in this range, karst cave roof has a great influence to the stability ofcave roof surrounding rock, out of this range, it will relatively small.（5）Soft mud-grout stones body can finish dilatancy in a shorttime(about8hours), using ratio of grouting water and mud as0.8:1, its eventually expansion volume is about3.1%of the original stones bodyvolume, according to grouting engineering specification, pressurecompaction grouting actions under the amount of expansion, effect is themost significant; and reduce the process of grouting construction, softmud cave reinforcement worked fast during the process of grouting to thecave roof roadway surrounding rock. To the modified engineering of thecave roof which is rich of ooze grouting, it is has a guide meaning.（6）Through engineering application, monitor the surrounding rockstress and deformation of Yongju coal industry10#roadway, resultshowed that: deformation shrinkage of roadway surrounding rock andloading of roof finally reached steady state, cave roof roadway groutingand supporting achieved good effect.