Tectonite Roof Failure Mode Identification Method And Its Application

The roof of the goaf is the weak part of it. The roof’s stability will directly affect the safety of mining personnel and equipment. At present, the analysis of goaf usually use a simplified mechanical model, while less use of the numerical simulation to evaluate quantitatively the stability of the goaf roof. Therefore, based on theoretical analysis, combined with the strength reduction and catastrophe theory, work and research on the stability of the gob roof is done as follows:(1) Summarized the research status of the goaf stability and strength reduction, emphatically analyzed the influencing factors of goaf roof’s stability and analysis method of the goaf roof.(2) Introducing the strength reduction into the goaf stability analysis, put forward a suitable analysis judgment reference of the goaf according to the three criterion of the slope stability analysis based on the strength reduction. Put forward the corresponding shear safety factor and crack safety factor according to the shear failure of the roof and crack damage.(3) Take the displacement evaluation for index, combined with the catastrophe theory and strength reduction, established the goaf displacement saltation model, realize the quantitative evaluation of the goaf’s stability.(4) Calculate the shear safety factor of the goaf and sidewall by numerical calculation of a simple model, and study the influence on the roof and sidewall from the rock mass cohesion, angle of internal friction, elastic modulus.(5) Analyse the failure mode of the gob roof and the occurring conditions, and ultimately realize the three main roof instability mode determination of the arch caving, bending and breaking, and the overall collapse of in the numerical simulation.(6) Established an iron mine in Xinjiang numerical model, analyse the roof displacement of the settlement after the stoping of inter-pillar and room, calculated roof safety factor combined with the cusp catastrophe theory and strength reduction, and judge the most likely instability modes of the goaf roof.