Study On The Overlying Strata Failure Laws Of Working Field And Its Calculation Consultation System

Firstly, based on the fracture and elastic-plastic mechanics, combining closely the underground pressure theory with the special mining theory, establishing every kind of mechanical model on the process of overlying strata failure and analyzing each of them respectively, analyzing dynamic mechanism about the height of water flowing fractured zone in boundary higher than the middle, the paper finds out the overlying strata failure condition when the highest point of its water fractured zone lies inside or outside after mining.Influences of overlying strata failure height of different exploitation methods, programs and geography terms are analyzed. The overlying strata failure height does not accord the linear relation with mining thickness in fully mechanized sub-level mining, but present the similar fraction relation. The height of water flowing fractured zone will broaden absolutely if firstly extraction height of thick coal or fully mining all height of coal and increase the full thickness of a falling -off form. Moreover, the height of water flowing fractured zone will increase little if several mining thickness is increased.The fuzzy judgments criterions of rock layer equivalent compressive strength σ are studied, and the judgments of rock layer soft hard classification standards are established. According to this classification standard, the judge method and formula of overlying strata failure height are established, and the calculation consultation system of overlying strata failure height is established by Visual Basic. The research results have certain theory significance and use value not only to the fundamental research but also to the project practice; especially to the enhancement forecast precision and automation.