Study On The Effect Of Grouting And The Early Warning Of The Superhigh-water Material In The Old Mining Area

The eastern mining area in our country are mostly near the city. With the rising value of the land, making full use of old subsidence land becomes an urgent solution in many cities and mining areas. To ensure the liberation of subsided land area and the safety of buildings, the residual deformation controling of old goaf is the core. Because of good liquidity, and low cost, superhigh-water material were used to fill mining and has made good effect in recent years in several mining areas. Presently, few practice and researches are few using superhigh-water material in old goaf grouting. Therefore, the research using superhigh-water material to reduce subsidence of the grouting effect has great significance for this technology’s optimization and promoted application.Superhigh-water grouting to reduce subsidence in square underlying goaf of JuLong coal industry, Han mining group is as the background. The high accuracy and high frequency subsidence monitoring to the grouting area are carried on; Using the EMD method to deal with the monitoring data, the old goaf subsidence characteristic under grouting condition are researched; ARMA model is used for dynamic warning in the monitoring process; Contrasting the expected results of probability integral model and the measured results, the grouting effects of sink reduction is analyed. The results of above researches are as follows :(1) 50 subsidence monitors to the grouting area are carried on, gaining the old goaf subsidence characteristic under grouting condition. The EMD method are applied to decompose the subsidence rate, obtaining a number of eigenfunction IMF and remainder r. After analysing the waveform curve, the results obtain that: during the grouting, IMF’s amplitude and frequency are enhancing, and remainder r has in the varying degrees raise tendency; efore and after grouting, the IMF and remainder r basically stable, and after the grouting, the sedimentation rate is smaller, whichshows that slurry has filled the part hole and crevasse, strengthening the stability of surrounding rock.(2) ARMA model is used to build eigenfunction IMF and remainder r model respectively. For short-term forecasting, relative error of the EMD-ARMA model may achieve in 20%, therefore it can be used for early warning. To make the dynamic subsidence prediction under non-grouting condition during the grouting effect period using the EMD-ARMA model, it can be seen that the grouting reduce subsidence effect was very obvious.(3) During monitoring, probability integral method is used to predict the residual deformation, The whole monitoring area can be divided into the grouting area, grouting influence area and grouting non-influence area, reduce subsidence of the grouting effect is gradually reduced.(4)Using the EMD method for main shaft hoist room stability analysis, found that after a period of time of grouting over, building is at the steady state basically, the sedimentation rate and speed oscillation amplitude is under the good control.