Research On The Law Properties And Damage Mechanism Of Gangue Roadside Filling Materials

Gob-side entry retaining method were one of the advanced green coal mining methods in China,It not only saves time,labor and economic costs for the layout of roadways in adjacent working faces.But,as an important part of roadway retaining method,the strength of backfill body is closely related to the characteristics of gangue and the content of auxiliary materials.Therefore,in this paper,the gangue is divided into coarse and fine aggregate to obtain the basic mechanical parameters such as apparent density,crushing value,et al,the effects of cement,fly ash and micro silica fume on roadway side filling materials were studied,and the working performance and strength characteristics of backfill material are analyzed,the mechanical and acoustic emission characteristics of backfill materials at roadsides under different.Experimental conditions and environments were emphatically studied,and the crack evolution and penetration law were systematically analyzed,the main conclusions are as follows:(1)According to the overburden control theory,the roadway side filling material must have good working performance;It must have corresponding early and late strength.This paper studies the working and mechanical properties of different auxiliary material ratios and gangue cementation molding process,defines the direct interaction relationship between auxiliary materials and gangue aggregate,and obtains the best ratio of auxiliary materials and gangue in roadway side filling materials.(2)The data of internal activity and compressive strength change process of filling materials are collected by acoustic emission and pressure testing machine,and the variation laws of acoustic emission signal and stress-strain during the test of roadside filling materials under different loading rates,pH values and humidity are analyzed,The relationship between internal energy change and stress-strain of materials under uniaxial compression under different conditions is obtained.(3)By analyzing the crack evolution process of the specimen under different conditions and environments,the surface crack evolution law and penetration mode of the specimen are found,and the compression failure mode,failure mode and internal energy change law of the filling material are obtained,so as to master the deformation failure,crack evolution and penetration law of the filling material.(4)Combined with the analysis of experimental data,through formula derivation and theoretical analysis,the relationship between acoustic emission cumulative hit number and stress-strain is studied,the relationship between cumulative hit number and strain is coupled,and the constitutive model of damage factor and cumulative hit number is established.