Study On Water Stability Of The Gangue-made Railway Embankment In Mining Subsidence Area

Embankment of the railway coal handling line over mining subsidence areas israised and widened in the process of surface subsidence, under mining or rainfall orrapid drawdown condition, the embankment slope facing stability problems. Thisthesis takes a mining area project in huainan using methods of elevation and wideningto reinforce the railway coal handling line embankment, and the local engineeringgeological conditions as the research background, takes the coal gangue materials of amining area in Huainan as the research and applied materials. Through using thecombinative research method of coal gangue physical and mechanical experiment,FLAC3Dnumerical simulation experiment, grey correlation degree analysis andengineering application, systematically studied the water stability of the gangueembankment slope of railway coal handling line, finded the most unfavorablecombination of factors, proposed optimal section forms of embankment slope, and putforward reasonable reinforcement programs to the embankment slope that does notmeet the stability requirements after using the calculations results to e ngineeringapplication. The study obtains the following main achievements:(1)The gangue filler has good permeability, k=1.06×10-4cm/s. When degree ofcompaction within a certain range, the permeability coefficient is in exponentialrelationship with the degree of compaction and the porosity of coal filler.(2)The physical and mechanical parameters of coal specimen were changedunder soaked conditions, along with soaked time increase, the filler gradually reachsaturation, its physical and mechanical parameters gradually approache a stable value,the cohesion decrease76.15%, the friction and elastic modulus substantiallyunchanged.(3)Factors of mining, rainfall and rapid drawdown conditions could influence theembankment slope stability of railway coal handling line, the mining conditions andrainfall conditions combined into the most unfavorable conditions.(4)Under the most unfavorable conditions, stability of embankment slopes onsilty clay soil and clay soil is good. When embankment slopes located soft soilfoundation, its stability is bad,it’s mainly controlled by the mechanical properties offoundation siol. The reinforcement measures of " set anti-slide pile, set back bermwith geotechnical grille " can effectively improve the stability of embankment slopes on soft soil.