Study On Pre Assessment And Dynamic Early Warning Of Multi-source Ground Pressure Disaster In Stope

In the process of mining,ground pressure disasters such as roof subsidence,floor bulging,section reduction after roadway deformation and surface collapse may occur.The influencing factors of ground pressure disasters are not only determined by monitoring the size of stress value,displacement and deformation,but also related to lithology,rock mass quality grade,fracture occurrence distribution,mining disturbance degree and other factors.There are many indicators and complex weights,It is difficult to determine,which leads to the poor accuracy of ground pressure disaster prediction.Therefore,in order to ensure the safety and stability of mining,it is very important and necessary to implement multi-source monitoring and risk early warning of stope ground pressure by comprehensively considering these multi-source determination and uncertainty factors.Through theoretical analysis,field verification,computer programming and comprehensive analysis and other methods and technical means,combined with two metal mine engineering examples,this paper plans to carry out the research on multi-source ground pressure disaster pre assessment and dynamic early warning in stope,and develop a multi-source ground pressure dynamic early warning platform.The main achievements of this paper are as follows:(1)Taking five indexes such as rock uniaxial compressive strength,rock mass integrity coefficient,groundwater conditions,structural plane conditions and mining environmental factors as pre evaluation factors,a combined weight set pair analysis pre evaluation model of ground pressure risk is established through set pair analysis theory,entropy weight method and analytic hierarchy process.Through the calculation and analysis of an iron mine in East China,the results show that 5~#and 7~#sample grades are grade IV,belonging to a high degree of risk,which is consistent with the actual monitoring results on site.Compared with a single method or subjective decision-making,the pre evaluation model can determine the key monitoring areas more reasonably and reliably,and can effectively improve the follow-up ground pressure monitoring effect.(2)Taking eight indexes such as RMR value,roadway buried depth,support mode,maximum principal stress,stress difference,maximum principal stress change rate,stress difference change rate and mining disturbance as the evaluation factors of ground pressure dynamic monitoring,a dynamic evaluation system of ground pressure risk degree is constructed.The d-number preference matrix is used to deal with the incomplete subjective evaluation information,and the critical method is used to calculate the objective weight.Combined with the multidimensional cloud model that fully considers the randomness and fuzziness between the data,a multi-source ground pressure dynamic early warning model is constructed.Through the verification of 20 groups of actual monitoring samples from an iron mine in South China,the results show that the coincidence rate between the model ground pressure risk level evaluation and the field actual risk level is 90%,which has a good monitoring and early warning effect,realizes the multi factor coupling evaluation of ground pressure risk level,and helps to improve the safety of mining work.(3)The automatic monitoring and multi-level visualization of ground pressure in a 200m iron mine area has been developed to meet the requirements of automatic monitoring and multi-level monitoring of ground pressure in a 200m iron mine area,which can greatly improve the dynamic monitoring and multi-level monitoring of ground pressure in a 200m iron mine Ground pressure monitoring was carried out in the areas with high potential ground pressure risk in the middle section of 0m in the West District,and more than 40000 ground pressure monitoring data were obtained.The overall monitoring is reliable and effective.There is no ground pressure safety accident in the monitoring area,which not only effectively ensures the safety and orderly production of the mine,but also provides effective guidance and data support for the safety work of the mine.