Study On The Stability And Control Technology Of Surrounding Rock Of Shallow Roadway Close Above Goaf

Coal field which is characterized by rich coal resource with thin overlying rock mass innorthwest China, is easy to occur omitting a little shallow seam mining. Because of shortdistance from coal seams, preparation roadway is strongly subjected by lower goaf. To ensuresafe of shallow roadway close above goaf, the position between goaf and roadway is requiredto determine. In this paper, we take Liang Shui-jing coal mine as research base, and in viewthe geological condition of thin overlying rock, shallow burial depth and thick loose bed inthis coal mine, analyze on the overlying rock mass movement rule, stability and supportingtechnology about surrounding rock of roadway within overlying rock.(1) Based on data of geologic survey, the characteristics of shallow seam with thinoverlying rock shows: shallow seam has thick loose bed, thin overlying rock and the smallthickness ratio of rock. Being different from weathering upper strata, the surrounding rockwith deep burial presents is composed by hard, compact and layered sedimentary rock.(2) Based on integral method, the subsidence and horizontal movement function aboutrock unit in overlying strata is established by mining influence function about rock unit.(3) The prediction of overlying strata movement rule of4-2seam in Liang Shui-jing coalmine is used by theoretical calculation and numerical simulation. The result shows that theinfluence of roadway stability by goaf is weak under the condition of the width of coal pillarbetween preparation roadway in3-1seam and boundary of4-2seam goaf is more than60m.(4) Surrounding rock of shallow roadway with mining influence is controlled effectivelyby anchor-cable collaborative support. And stability of local surrounding rock is controlledineffectively by U-shaped steel support and bolt net support. To weathering surrounding rockwithin3-1coal seam, anchor-cable collaborative support is formed effectively under theconditions of which anchor and cable are applied respectively in pre-tightening force of40kNand100kN.