QIN Siqing, WANG Sijing. 2005: INSTABILITY LEADING TO ROCKBURSTS AND NONLINEAR EVOLUTIONARY MECHANISMS FOR COAL-PILLAR-AND-ROOF SYSTEM. JOURNAL OF ENGINEERING GEOLOGY, 13(4): 437-446.
    Citation: QIN Siqing, WANG Sijing. 2005: INSTABILITY LEADING TO ROCKBURSTS AND NONLINEAR EVOLUTIONARY MECHANISMS FOR COAL-PILLAR-AND-ROOF SYSTEM. JOURNAL OF ENGINEERING GEOLOGY, 13(4): 437-446.

    INSTABILITY LEADING TO ROCKBURSTS AND NONLINEAR EVOLUTIONARY MECHANISMS FOR COAL-PILLAR-AND-ROOF SYSTEM

    • This paper presents the instability mechanisms of a mechanical system that is composed of the stiff hosts(roof and floor) and the coal pillar by using catastrophe theory.It is assumed that the roof is an elastic beam and the coal pillar is a strain-softening medium which can be described by the Weibulls distribution theory of strength.The results indicate that whether the instability can lead to a rockburst largely depends on the systems stiffness ratio k and the homogeneity index m of the coal pillar.A nonlinear dynamical model,which is derived by considering the time-dependent property of the coal pillar,is used to study the physical prediction of rockbursts.An algorithm of inversion on the nonlinear dynamical model is adopted in the search of the precursory abnormality from the observed series of roof settlement.A case study of the Muchengjian coal mine is conducted.Its nonlinear dynamical model is established from the observation series using the algorithm of inversion.An important finding is that the catastrophic characteristic index D drastically increases to a peak value and then quickly drops close to instability.A dynamical model of acoustic emission(AE) is then established based on damage mechanics of coal pillars for modeling the AE activities in the evolutionary process of the system.It is concluded that the values of m and the evolutionary path of the system have a great impact on AE activity patterns and characteristics.
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