Research On Control Technology Of Chamber Surrounding Rock With Deep Soft Rock And Large Section In Hengyuan Coal Mine

Along with the increase of coal mining depth，the difficulty of roadway supportis gradually increasing. As the deep mining area in Hengyuan Coal Mine, when theconventional section roadway adopt conventional support method, roadwaydeformation is difficult to be effective controlled In view of this, the overheadmanned car chamber and winch room will face same problem which have largersection、environment further complicated stress and higer using requirements withsection, therefore, it has very important practical significance to study controltechnology of chamber surrounding rock with deep soft rock and large section.Studying on overhead manned car chamber and winch room in Hengyuan CoalMine and using combinative methods of field research, theoretical analysis,numericalsimulation calculation and on-site industrial test. characteristic of chamber group indeep mining was revealed, then analysising the effect of section size、buried depth andtectonic stress on the stability of surrounding rock of chamber by numericalsimulation software, putting forward crucial technologies for deep big section of softrock chamber, And then the paper carries out the field test. At last it makes evaluationon the effects with deep large section soft rock chamber control by field measurement.The results of stability with surrounding rock of underground chamber show thatthe larger section, the increase of buried depth, tectonic stress influence, The floor ofthe chamber is supporting key. It is timely for the large cross section chamber forsecondary support after first support, secondary support ought to be at the break pointfrom deformation violent stage to gentle stage.It is very harsh to control floor ofchamber，which needs to take measures of control floor. The paper comes up with afull-length cement end grouting cable anchor model. Not only has the process of longsliding framework and under-frame helped apply bottom anchor in big sectionchamber, but also improved the efficiency of construction. Pretightening force of boltsand anchorage cable should be reasonable matching which is a important parametersof bolt net support. The monitoring of prestress loss of bolts and anchorage cableshows that:1）The secondary pre-tensioning effect will better which have highertorque, In order to meet the requirements to achieve the initial pretension bolt, shouldbe based on300N.m bolt torque then have secondary pre-tension；2）In considerationof the fact that the prestressing loss of cable tensioning, oil pressure reading of tension machines should be enhanced from26.5Mpa to28Mpa to guarantee the initialtension force reaching100KN；3）Considering the prestressing loss of anchor fixingand grounding rock deformation, the loss of prestressing force rapidly in half an hour.over tensioning to the most of30Mpa is feasible.