| With the increasing of coal mining depth and intensity year by year,the number of mines and the risk degree of impact burst increase significantly.The traditional stress monitoring method has limitations to the monitoring of impact burst disaster.The calculation results of rock burst studied by traditional numerical simulation methods often do not match the monitoring data.In order to solve such problems,based on the concept of real-time interaction of digital twin,a shock burst monitoring and early warning system based on digital twin technology is proposed.Specific research is as follows:(1)Based on the measured data of the dynamic pressure sensor,the load expression function of the impact of the ground pressure is proposed,and it is applied to the digital twin monitoring and early warning system.The discrete point data are extracted based on the measured load waveform of rock burst,and the impact load was fitted by Fourier series model,the number of load function series terms is determined,and the spectrum characteristics of impact load are analyzed.Based on the load characteristics,the impact load expression function is proposed.Numerical simulation method is used to analyze the impact characteristics of impact load on roadway structure and the impact characteristics of impact load on typical three-core arch support to verify the practicability of load function.The study shows that the load function proposed by superposition the product of the sine function and the attenuation term can well express the impact load,and the load fluctuation period is linearly related to the attenuation rate.(2)Through the secondary development of ANSYS,the parameterized modeling of the coal seam and the roof and bottom plate is realized,and the twin body is constructed.Through the secondary development of ANSYS,the finite element model of the working face is parameterized,the finite element model considers the geometric features,such as geological structure and so on.The D-P criterion is determined to be the nonlinear material yield criterion in digital twin.Calculating impact critical stress risk assessment methods are proposed and applied to the digital twin monitoring system,and the secondary development is realized by parametric design language APDL.(3)Using Python language to build a digital twin framework,combined with ANSYS secondary development to achieve digital twin.A total of two main programs and nine subroutines are written,and the second development results of ANSYS were combined with the digital twin framework to realize the digital twin simulation.In this paper,the construction logic of digital twin framework,the joint secondary development of Python and ANSYS to realize the digital twin calculation method,and the information interaction method between Python and ANSYS through two levels of circulation are proposed.The results show that the model of coal seam roof and floor can invert the stress of measuring point to the boundary condition of stress load by constructing the linear function.(4)The engineering application of the digital twin system is carried out to verify the technical reliability and provide support for safe production.Based on the actual engineering background,the finite element simulation model is constructed,and the reliability of the digital twin calculation results is verified by comparing with the traditional numerical simulation results.The digital twin monitoring method is used to continuously monitor the down hole stress state,and the error analysis of continuous monitoring results is carried out,predict whether rock burst appears in the mining process and the trend of the impact risk in the mining area,evaluate the impact risk of mining area under impact load.The results show that the numerical twinning method is more accurate than the traditional numerical simulation method.The impact risk index of the working face is reduced;the change meets the index function.There are 88 figures,12 tables and 90 references in this paper. |
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