Experimental Study On Anchorage Reconstruction Of Fractured Rock Mass

The structural creep of fractured rock in plastic zone is the main reason for large deformation of roadway surrounding rock,and large deformation of roadway surrounding rock restricts the safe production and efficient mining in deep mines.Anchor support is the most common and effective support means to control the deformation of surrounding rock,and the anchoring mechanism,anchoring effect of fractured rock and anchoring parameters of deep roadway are the key to ensure the reasonable and efficient support,which is of great significance to deep mine mining.Therefore,based on laboratory tests and field tests,this paper explores the influence of the degree of crushing in the crushing zone and the thickness of the crushing zone on the mechanical properties of the rock body during the loading process,and explores the anchoring mechanism of the rock surrounding the deep roadway and the anchoring characteristics of the crushed rock body.The results show that the peak strength of the specimen decreases with the increase of the grain size.When the grain size of the specimen is small,the stress decreases more rapidly in the residual bearing stage after the stress peak,and when the grain size is larger,the stress decreases more slowly in the residual stage after the stress peak.The larger the particle size,the larger the pores in the crushing zone,the faster the fracture development and expansion during the loading process,the stronger the acoustic emission response before the stress peak,and the greater the counting frequency and energy accumulation;for specimens with different crushing zone thickness,the stress peak of the specimen gradually decreases with the increase of the crushing zone thickness,and there is an obvious lag between the acoustic emission counting and energy accumulation peak compared with the stress peak;for The anchoring of the specimens significantly improved the strength of the specimens.The peak strength of the specimen and the number of anchors obeyed the exponential relationship,and the peak strength of the specimen and the number of anchors obeyed the linear relationship,and the R2 was greater than 0.99,which was a good fit.The peak strength of specimens parallel to the axial loading direction is higher than that of specimens perpendicular to the loading direction.Taking the 1700 transport road of Jieda coal mine in Yunnan Province as the background,we designed a support scheme with "hollow grouting anchor cable" as the main body and "grouting anchor + metal mesh + anchor spray" as the auxiliary one,taking into account the characteristics of the roadway with large deformation,convergence of the two gangs,sinking of the roof and serious bottom drum.The proposed new support scheme is compared with the deformation and damage of unsupported tunnel rock by numerical simulation,and the scientificity and rationality of the integrated support scheme of "grouting anchor rod +reinforcement mesh + slurry spraying + hollow grouting anchor cable" is explained in terms of plastic zone,stress field,displacement field and deformation of the support structure.