Study On Random Parameter Model And Response Rules Of Mining Strata Structure

The development of large-scale underground geotechnical engineering construction planning projects is accompanied by major disasters and accidents.It makes the study of safety and reliability of engineering design more and more important under complex geological conditions,especially the mining design and safety protection of deep mineral resources.Dynamic disasters occurred with randomness in the process of deep development of mineral resources mining.Dynamic disasters include rock burst,roof breaking,rock burst and other geological disasters.These disasters have the characteristics of high incidence and high harm.The reliability of disaster prediction is low.Due to the randomness of geological environment factors and heterogeneity of rock materials,it is uncertainty in the dynamic characteristics of rock structure.Taking the west No.3 mining area 7# coal working face of Hongyang No.3 coal mine as the engineering background.Study the random dynamic response characteristics of rock structure system with random factors.The mechanical parameters of large sample rock specimens are tested to analyze statistical characteristics of parameter datas.The RVMS2017-01 rock random dynamic test and analysis experimental system device is developed.Based on the above device,design indoor random dynamic response experiments of single rock block and rock block assemblage samples.The statistical laws of characteristic parameters of rock sample response are analyzed in time domain and frequency domain.The random field theory and dynamic control theory are introduced to establish the dynamic control equation of random parameter structure of mining rock strata.Through physical similarity simulation,the variation laws of stress field and displacement field of mining rock strata is analyzed under external random disturbance.The mean value parameter structure model of selected rock strata is established.The distribution characteristics of stress field and displacement field for mining roock strata are simulated during excavation.The random parameter structure model of selected rock strata is established.The influence of random elastic modulus on the response additional term of mining rock is considered in the numerical analysis.The results show that:(1)The uniaxial compressive strength,elastic modulus and uniaxial tensile strength of sandstone specimens obey normal distribution,and Poisson's ratio obeys Weibull distribution.(2)Under random impact disturbance,the randomness of the time-domain characteristic parameters of response for rock block samples is smaller than that of the external excitation.In frequency-domain,characteristic parameters of signal transfer ratio of response to excitation can better describe dynamic characteristics of rock structure.The energy concentration occurs in the interlayer dynamic transfer process of the rock block assemblage samples designed.For external disturbance,the dynamic transmission of rock structure system has frequency selectivity.(3)In the process of similar simulation excavation,the vertical stress of direct roof fluctuates obviously and accelerates stress concentration of direct roof.Compared with the traditional simulation results,roof periodic weighting time is advanced,fault zone is widened and the dip angle is increased under external random disturbance.(4)The stress and displacement of direct roof of mean value parameter structure system under excavation disturbance have obvious fluctuation range.At the moment of excavation,the kinetic energy of mining rock strata is rapidly accumulated and released.The maximum strain energy appears at direct roof at the front end of the mining section.(5)The variability of additional stress and vertical additional displacement is stronger than that of total stress and vertical total displacement.The coefficient of variation of additional stress is greater than that of elastic modulus.The 3? range of the additional stress and vertical additional displacement of direct top increases with increase of coefficient of variation of elastic modulus.The 3? range fluctuation is the most obvious from horizontal middle position of direct roof,because tensile stress appears in the fluctuation range of additional stress.The random parameter structure model should be used to analyze the variability of additional items in response of mining strata for mines with strong impact tendency.The simulation results have theoretical guiding significance for design of excavation speed and help to evaluate dynamic disasters such as rock burst.The research results have theoretical guiding significance for dynamic response analysis and rock control reliability analysis of mining-induced rock structure system under complex geological conditions.There are 146 figures and 22 tables and 151 references.