Research on"two-stage"collaborative early warning method for roadway rock deterioration
The assessment of the degree of deterioration of surrounding rock in a roadway is a critical issue for the prediction of roof disasters,which are essentially caused by the microstructural evolution inside the rock mass.In this paper,a combination of nuclear magnetic resonance technology,numerical simulation,and energy theory is employed to investigate the pore evolution laws from small,medium,and large aperture pores and cracks to macroscopic failure during rock loading,as well as the associated energy evolution laws.The unification relationship between the"pore evolution stage"and the"energy evolution stage,"which forms a"dual-stage"evolution process,is elucidated to establish a quantitative characterization of the microstructure of rock and the degree of deterioration of surrounding rock in a roadway.The results show that the distribution characteristics of porosity evolution during uniaxial loading of the specimens are obtained,and the porosity evolution is divided into four stages:pore compaction stage,elastic deformation stage,elastic-plastic deformation stage,and plastic yield stage.The mechanism of the differences in the characteristics of the pore evolution stages between laboratory tests and numerical simulations during the pore evolution process is revealed,which is caused by the elastic deformation recovery of the specimen during the unloading process of the laboratory test.The consistency between the"pore evolution stage"and the"energy evolution stage"during the synergistic evolution process is demonstrated,and the"dual-stage"synergistic evolution process curve shows a basic consistency in normalized values,indicating a micro-macro cross-scale unification relationship between the two.A roadway surrounding rock deterioration and failure warning method based on micro-macro cross-scale rock structure synergistic evolution is constructed to comprehensively evaluate the degree of rock deterioration,give corresponding warning levels for the rock strata in the relevant areas,and provide a theoretical basis for on-site safety hazard prevention and control work.
rock mechanicspore evolutionenergy evolutionenclosing rock deteriorationquantitative characterizationcollaborative early warning
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