Evaluation On Ground Grouting Treatment In One Jincheng Coal Mine Goaf

With the rapid progress of China's urbanization process,the construction land is increasingly tense,and more and more coal mine goaf sites are applied to engineering construction.The treatment of ground grouting and reinforcement in coal mine goaf has become an important issue.This paper takes the site of the coal mine goaf in a residential district of Jincheng as the engineering background,studies the evaluation on ground grouting treatment in coal mine goaf.The main contents and conclusions are as follows:?1?Evaluate the foundation stability of a residential quarter in Jincheng,so as to provide a theoretical basis for further design of grouting treatment project.Through stability evaluation and analysis,it is concluded that the influence of 3^#coal mine goaf on foundation stability should be considered in 1^#building,2^#building and 5^#building.?2?The law of the subsidence deformation of the basement of the goaf is S and the compression settlement of the basement of the goaf is S₁,the residual settlement deformation of the goaf is S₂ and the"activated"settlement deformation of the goaf foundation is S₃,so S=S₁+S₂+S₃.Designed the grouting treatment scheme,calculated the grouting range,depth and works,determined the number and position of the drill hole layout,selected the suitable hole forming process,pulping process and grouting process.?3?Through the indoor ratio test,it is found that cement fly ash slurry is used for grouting treatment in the collapse area of the 3^#coal mine goaf in the subsoil of the residential district.The grouting hole is selected as water solid ratio 1:1.1 and solid ratio3:7,the curtain hole is selected as water solid ratio 1:1.2¹.3 and solid ratio 3:7,adding2%water glass is better.The cavitation area of 3^#coal mine goaf is treated by grouting with cement fly ash and fine aggregate slurry,the water binder ratio is 0.5 and sand rate is 0.4.?4?Using comprehensive geophysical prospecting,drilling and surface deformation monitoring methods to evaluate the grouting,it is concluded that the filling is good,the filling rate of slurry is 98%,the stone rate is 89%,the compressive strength of the stone body is 4.02 MPa,and the grouting meets the design requirements of the 3^#coal seam goaf.The cumulative settlement of ground surface decreased obviously after grouting,and the trend of change increased with time.