1、第128页翻译部分英文原文The dynamic impact of rock burst induced by the fracture ofthe thick and hard key stratumFENG Xiaojun,WANG Enyuan,SHEN RongxiState Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221008, ChinaAbstract:To reveal the dynamic impact of ro
2、ck bursting induced by the thick and hard roof of gravel as key stratum fractured,based on the key strata and rock control theories,combined with the mechanical load-based dynamic loading with the Law of Conservation of Energy in a system,this paper analysed the static stability and the processing o
3、f energy conversion within the system when the key stratum was fracturing.And the key stratum dynamic model of fracturing was established.The results indicate that large amounts of strain energy would be forced into the rock during the process as the key stratum fractures and becomes unstable.The gr
4、eater the dynamic load factor is,the more elastic energy is forced into the lower rock strata of the key stratum,and the more obvious the dynamic impact of the lower rock strata would be.The size of the dynamic load factor relates to the aspect ratio of key rock masses,the thickness of the overburde
5、n,the mining height,the height of the fragmentized rock at the bottom of key stratum and the compaction coefficient of the fragmentized rock under the static during loading conditions.According to the calculation of actual work,the results are consistent with the field tests approximately.The result
6、s can provide references to similar conditions.Keywords:key stratum;rock burst;dynamic loading;energy constant1.IntroductionThe key stratum controls the overlying rock strata,even to the surface,with high strength,high thickness,and overall subsidence of overlying strata happen easily when it fractu
7、res1-3.The key stratum that has different lithology,strength and thickness impacts the control of the rock strata and the dynamic impact of rock burst after it fractures4-7.As the key stratum,the thick and hard roof with gravel is controlling the movements of the entire overburden,because of its cha
8、racteristics of high strength,high thickness,fracture would not happen until the area of mining space reaches a value that is big enough8.The whole overburden even surface sinks the surface instantaneously when it fractures, causing a release of strong dynamic force on the rock strata below the key
9、stratum.With the increasing in the strength and depth of mining exploitation,the dynamic impact of rock burst will be more and more important when the key stratum fractures suddenly,and the support designs and the hazards of rock burst induced by dynamic effects continue to increase9-10.The previous
10、 have developed comprehensive and systematic studies on rock control,mining damage and the mechanism of water inrush at the overburden separation area11-14.Reference15discussed the impact on the height of water inrush caused by the location of key stratum,and explained the mechanism of water inrush
11、in some coalmines accidents.Reference16discussed the stress of the compound key stratum with the Elastic Thin Plate Theory and Laminated Plate Theory of the mechanics of composite materials,and obtained the limit load when the key stratum was unstable by using plastic limit analysis methods,regardin
12、g the combined motion of rock strata overburden as the combined motion of the key strata based on the hard rock strata.Reference17discussed the mechanical mechanism that it could easily cause mining earthquake and rock burst occurrence when the key stratum broke off in positiveO-Xtype,and by monitor
13、ing the rock burst induced by the fracture of the key stratum instantly in three-dimensions using the micro seism monitoring system.As the key stratum fracture is a dynamic loading process to the lower rock strata,causing the loading process of rock fracturing is different from the general static lo
14、ading conditions,it is necessary to conduct researches on the rock burst induced by the fracture of the key stratum.This paper established the dynamic model of the key stratum fractured and derived the dynamic load factor when the dynamic impact loading on the lower strata by combining the theory of
15、 the mechanical load-based dynamic loading with the law of conservation of energy of system, we analysed the static stability and the process of energy conversion within the system when the key stratum was fracturing.Confirmatory calculation of actual work was also done,which was consistent with the
16、 field tests approximately.The results can provide references to similar conditions.2.Subsidence profile curve of the super mining explorationThe super mining exploration is the critical mining state that the width of goaf is larger than 1.2 to 1.4 times the depth.Compared with the full exploration,the maximum subsidence in the central of the super mining exploration shows:the distribution of the maximum subsidence presents regional characteris
