Mechanical Characteristics Of Rock Mass Discontinuities Under Dynamic Disturbance And Application In Open-underground Combined Mining

The slope of open-pit coal mine contains a large number of discontinuous rock mass discontinuities with initial damage.The structural form,the space distribution and the mechanical behavior of rock mass discontinuities controls the stability of slope engineering,in the phase of open-pit combined mining,the dynamic disturbance will further damage the structural plane of rock mass slope.Based on the Anjialing mine of China Coal Pingshuo Group Co.,Ltd.,this paper studies the mechanical characteristics of rock mass discontinuities under dynamic disturbance and its application in open-pit ground combined mining engineering by means of laboratory test,theoretical analysis and numerical calculation.According to the characteristics of structural surface morphology,filling condition and continuity of slope rock mass,the calculation method of shear strength and its strength effect under dynamic disturbance are studied.Through the uniaxial test study of rock mass discontinuities under cyclic dynamic disturbance,the result was obtained that mechanical characteristics and failure characteristics of rock mass discontinuities with different dip angles under dynamic disturbance;The expression of the disturbance threshold whether rock mass discontinuities destroyed or not in the disturbance cyclic loading is determined.And a cyclic loading-unloading constitutive model of the rock mass structure considering the influence of the disturbance threshold is construct;Based on the catastrophe theory,the cusp point mutation model of rock mass structure under dynamic disturbance is conducted,and Mutation instability criterion of rock mass discontinuities under dynamic disturbance was proposed,and also the dynamic model of filling structure surface is set up,which studies the influence of inclination Angle,static load,dynamic disturbance amplitude and disturbance number on the failure of rock mass discontinuities;Through the soft rock rheological perturbation effect under the different water content and different coaxial pressure,the effects of horizontal stress,water content and disturbance load on creep of structural surface rock are studied,and the constitutive model of rock mass discontinuities based on rheological perturbation effect was established.Establish the underground mining and overlying strata movement structural model of "voussoir plate" which result in open-pit slope instability,put forward the judgment of structural instability;Through the secondary development of Flac3D custom constitutive model,the stress state of the north slope of Anjialing slope under the influence of underground mining and dynamic disturbance is analyzed.FinallyThe deformation and failure mechanism of open pit mining slope is expounded from creep disturbance effect of rock mass discontinuities and "creep disturbance activation" in goaf.The research results not only have important academic value,but also have a strong guiding significance to the practice of open-pit joint production engineering.There are 61 figures,7 tables and 112 references in this paper.