| The comprehensive treatment and ecological restoration of coal mining area in the east of China is a major problem.The problem of land subsidence caused by mining activities is more and more prominent.How to solve the problem of land subsidence in coal mining has been highly valued by scholars in the mining industry.In order to control the land subsidence caused by coal mining,the paper comprehensively uses the methods of numerical simulation,theoretical analysis and field measurement to carry out the research on the principle,simulation and field test of grouting and filling in the loose layer at the top of the bedrock.The subsidence reduction by grouting and filling in the loose bed of bedrock top boundary of working face is simulated.Through comparison and analysis are drilling and grouting at the mining land mobile deformation condition,the land sink reduction rate was 61% after grouting and land deformation in coal mining subsidence land level ? destroy the allowed range,to verify the technology has significant effect of heavy,also prove the feasibility of this technology has the governance of land subsidence.Based on this,the paper analyzes the different grouting quantity and mining in surface mining and grouting,the change rule of vertical mobile bedrock top boundary is given brief calculation method,the amount of loose bed grouting surface subsidence,this paper expounds the principle of loose bed grouting heavy reduction analysis the effect of grouting quantity on the sink of the rule of the grouting amount,the greater the formation,the greater the level of plasma pulse volume expansion for the formation of the uplift,the greater the amount of surface sink reduction effect,the better,and accords with the general law of actual engineering.The influence law of different injection-production ratio on surface subsidence reduction was studied.By analyzing the observation data of surface subsidence after grouting,validate the simulated values and measured values of surface movement deformation height,based on this,research the influence of different injection-production ratio on the surface the effect of heavy law,analyzes the different injection-production ratio and surface deformation value and reduce subsidence and filling body thickness and grout diffusion distance dynamic change law of four indicators,and how the change of these indicators reflect the surface sink reduction effect,obtained the injection-production ratio,the greater the thickness and surface reduce subsidence rate,filling body of grout diffusion range,the greater the largest mobile deformation is smaller,reduce subsidence of the loose bed grouting filling effect is better.At the same time,the quantitative relationship between injection-to-production ratio and surface movement deformation value is obtained,and the relationship between the two is inverse.The larger the injection-to-production ratio is,the better the surface subsidence reduction effect is,and it conforms to the general law of grouting and filling engineering,and the optimal injection-to-production ratio of actual engineering is obtained by comprehensively considering the engineering cost and the control requirements of surface subsidence.The subsidence control effect of grouting in loose bed of bedrock roof boundary was evaluated.Three grouting holes were arranged in the test working face,with the grouting filling capacity of 40,100 t and the injection-production ratio of 18.6%.The maximum subsidence in the measured grouting area is 475mm(less than the critical subsidence amount of 500mm),the average surface subsidence rate is 68.3%,the land reclamation rate is up to 100%,and the surface is still under normal cultivation.The results show that the technique has a significant effect of reducing the sink,and solves the problem of mining subsidence land management,and the filling cost of tons of coal is only about 10 yuan,so the economy is better.This paper contains 33 figures,7 tables and 99 references. |
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