Feasibility Study On Natural Gob-Side Entry Retaining And Engineering Practice

Gob-side entry retaining is one of common methods to solve the problems such as low coal recovery ratio,mining and development replacement incoordination.Natural gob-side entry retaining,with hydraulic support but without filling wall or coal pillar,which is widely used because of technology economy advantage.Its advantages are proved by a series of industrial experiment in LaoMuPo Mine,LanHuaBaoXin Mine and so on.This paper investigates the feasibility and applicability of natural gob-side entry retaining based on the background of workface 2104 and 5101 in LaoMuPo Mine.The key to successful engineering practice is lateral roof collapse timely,so this paper study the structure model of natural gob-side entry retaining,and put forward the calculation method of lateral roof's limit collapse drawing pace.This paper think that gob-side entry surrounding rock form stable structure with support system in roadway beyond the influence of mining.Put the roadside support system in the range of roof limit collapse drawing pace,providing sufficient holding power,can ensure lateral roof breaking timely and form stable gob-side entry space.Take workface 5101 in LaoMuPo Mine as a research sample,and analyse the rock physical and mechanical properties of gob-side entry retaining roof and floor,then develop numerical simulation on this basis.The analysis results show that after mining the stress increases drastically in front of stope,and the stress gradually decreased to rock stress when the distance is more than 40 m.The stress in goaf is gradually stable with residual support strength.The stress in gob-side entry stay stable,and stay focus in roadway wall,mostly in goaf side.The whole process of mining present a characteristic of sensim collapse,which means the rock deformation gradually increases then become stable,and the deformation velocity increases at first then decreases.Based on the study mentioned above,analyse the important influence factors of gob-side entry stablities,and design orthogonal test to study multiple factors numerical simulation.The research result show different rock deformations in different conditions,then build a database of engineering conditions and results.Combined analytic hierarchy process and fuzzy mathematics to research the database above,then build a prediction model of rock deformation and calculate the factors weight,finally form a standard of comprehensive evaluation and support parameter recommendation.The research result of the paper is mutual verification with engineering practice of workface 2104 in LaoMuPo Mine,provide the feasibility and applicability evidences of natural gob-side entry retaining from theory and practice view.This paper is full of significantly social and economic value.