Study On Mechanism And Prediction Of Pillar Rockburst Based On Catastrophe Theory

The mechanism and forecast of Rockburst for ore pillar is a hot as well as a complicated research spot in the fields of mining engineering at home and abroad. It is difficult to account for the rockbursting with conventional theories. Catastrophe theory which is based on analysissitus and singularity theory is a specialized mathematical tool for the analysis of Catastrophe phenomenon. It use mathematics model to study the rule of the emergent change in a system and the discontinuousness of the system at critical point. Thus, the naissance of Catastrophe theory provide a new routine to the study of gusty and no-linear dynamics phenomenon of rockburst.With the Finance support of the Hunan national science fund (05JJ100100) and basing on the previous work on rockbusrt mechanism and prediction, this paper applied the catastrophe theory to study the mechanism of rockburst for ore pillar on the effect of symmetric exploitation, asymmetric exploitation and dynamics disturbing. Through a comprehensive considerations of the effect factor of rockburst, the fisher discriminate analysis theory (FDA) in statistics was used for the first time to construct the prediction model of rockburst. And, the constructed model was utilized in the rockburst forecast of several actual engineering. The primary content of this paper are as follow:(1) A review on the research results and currents of the mechanism of rockburst was performed. The shortcomings of previous works on the mechanism of rockburst was analyzed. The significance of the construction of the adequate system potential function was pointed out.(2) From the energy principle, based on calculating rock beam tocurve the equation accurately and in the application mutation statistics Catastrophe theory has discussed symmetrical mining and under the asymmetrical mining condition the pillar rockburst question, obtained rock beam - pillar system across bifurcation set have the Catastrophe necessary and sufficient condition. The analysis obtained under the different mining way the ore room safe mining span and the rock burst relations. The energy and the pillar has calculated separately under two different mining ways the rock burst occurs when releases kicks the value.(3) The outside perturbation load hypothesis is the overtone form, which has established the catastrophe model of double cusp. Obtained under the disturbance the pillar Catastrophe destroy criterion. Research that the rock beam-pillar system's non-linear factor's evolution can cause the system amplitude square unstable kicks the vibration, which will cause the pillar system's kinetic energy (or momentum) has the sudden change, then lead to the sudden impact or keep within limits, thus has had the big impact stress in the system, this will possibly be the pillar to occur rock burst disaster's one kind of mechanism.(4) Applied FDA theory to forcasting rockburst, A Fisher Discriminant Analysis (FDA) model to predict the possibility and classification of rockburst is established. The main control factors of rockburst, such as values of in～situ stressesσ_θ, uniaxial compressive strengthσ_c and uniaxial tensile strength of rockσ_t, elastic energy index of rock W_et,σ_θ/σ_c andσ_c/σ_t are regarded as the discriminant factors of the FDA model. Two actual engineering are predicted using this model. The results show that the FDA model of Rockbust prediction is accurate in forcasting rockburst. It is a new way to be used for forcasting rockbust.