Analysis Of Surrounding Rock Stability Of Tunnel With Nearby Goaf Of Small Coal Mine And Study On Relative Countermeasures

With the rapid development of infrastructure construction in our country, more and more roads, railway tunnel through the presence of various types is gob formation, especially western area. Small coal mining goaf is very irregular and difficult to detect, so it is a great danger to the tunnel construction safety. Study on surrounding rock stability of goaf tunnel has important significance.This paper taking Guizhou province reservoir tunnel as the basis, using comprehensive survey, field test, the theory and numerical analysis means of integrated, Study on surrounding rock stability of goaf tunnel, The main research as follow:(1) Using the geological radar and seismic scattering slope method to detect reservoir tunnel exit many coal mines of small kiln segment, combined with other relevant information, consolidation and analy the detect data, and confirme the related parameters of tunnel which may be surround with goaf.(2) For the tunnel overlying coal mine gob area, using Midas numerical software to build three-dimensional model, comparative analysis with or without goaf under two kinds of working conditions, study the stability of tunnel surrounding rock, kown that the mined-out area has great influence on stability of tunnel. This supplement calculation of pipe shed support to reduce the stability of the tunnel for gob effect, calculation, pipe roof reinforcement can reduce the goaf effect on tunnel stability.(3) Using the field test method, through the deformation of tunnel surrounding rock and supporting stress test analysis, research on the rock stability of goaf tunnel, combined with the actual construction, put forward to improve goaf tunnel stability measures.(4)As the tunnel of coal mine gob area size for an example, using Midas to establish a two-dimensional model. Considering the overlying goaf, inclined top45°, horizontal parallel gob, oblique below45°, mined-out area under five kinds of conditions, by changing the relative distance of the gob and tunnel, Using the crown settlement, lateral wall convergence, plastic zone and other indicators, obtain weak influence area and no influence area that coal mine gob influence on tunnel.