| Under the condition of deep mining,the phenomenon of strong dynamic load becomes more and more obvious,which leads to the loosening of anchor bolt(cable)anchoring,the failure of supporting components and the reduction of supporting strength,resulting in the instability of the anchoring bearing structure of roadway surrounding rock.In view of the problems existing in the stability control of roadway surrounding rock under the action of strong dynamic load,the prestressed full-length anchorage support is proposed to enhance the tensile and shear resistance of anchor rod(cable)and enhance the control ability of surrounding rock deformation.In order to achieve full-length anchor cable anchorage,a new type of inorganic anchor material is developed in this paper,which can be combined with the existing technology to achieve full-length anchor cable anchorage,thus reducing the failure of anchor components under strong dynamic load and controlling the serious deformation of roadway surrounding rock.Based on theoretical analysis,laboratory mechanical test,numerical simulation and industrial test,the action and failure mechanism of full-length prestressed anchor cable under static and dynamic load,the mechanical response and failure process of roadway anchorage bearing structure under strong dynamic load are systematically studied.The main research contents and conclusions are as follows:(1)The stress characteristics and vulnerable areas of the anchor cable under dynamic and static load are analyzed,and the variation characteristics of axial and shear stress of the full-length prestressed anchor cable under strong dynamic load are obtained.By establishing the full-length anchoring model of prestressed anchor cable and analyzing the stress and deformation characteristics of different regions in the range of the anchor cable,the method of strengthening the shear and tensile strength of the anchor solid is obtained,and then the stability of the anchor bearing structure is improved.Based on the dynamic and static load analysis of solid anchor cable,the strengthening mechanism of full-length anchor is discussed from the Angle of interface bonding state change.(2)The mechanical response and impact failure evolution process of surrounding rock anchoring bearing structure under strong dynamic load(end anchor and full-length anchor)are analyzed by numerical calculation.It is found that tensile shear stress caused by strong dynamic load is easy to cause deformation,damage and failure of the anchor carrier,which leads to the strength reduction of the anchor bearing structure and the failure of the anchor bearing system.The impact failure of the anchorage bearing structure is the result of the interaction between dynamic load and static load,and is accompanied by the accumulation and dissipation of energy.(3)A new type of inorganic full-length anchorage material has been developed,which has the advantages of short setting time,high strength,good expansion performance and low hydration reaction temperature.The main material is superfine cement-based material,and the modifiers are superfine fly ash,water reducing agent,expansion agent and accelerating agent.The content of each component of the new material is determined by single factor test,and the influence of each component on the properties of the material and the microscopic mechanism of action are studied.(4)The mechanical load bearing characteristics of the anchoring system of fulllength anchoring materials were studied,and the tensile resistance and acoustic emission response characteristics of the anchoring samples in the pull test under different anchoring materials were systematically compared and analyzed,and the bonding-slip relationship of the anchoring interface was obtained,and the anchoring load mechanical mechanism of different anchoring materials was clarified.It is proposed that prestressed end anchor and full-length anchoring are first used to enhance the coupling effect between anchor rod(cable)and surrounding rock to improve the bearing capacity of the anchoring system.(5)The dynamic disturbance test system of roadway surrounding rock is used to study the impact mechanical response,deformation and failure characteristics of anchor solid under dynamic load with different anchoring materials and anchorage methods,and the law of crack development and evolution is analyzed.It is concluded that full-length anchoring can enhance the coordination between anchor rod(cable)and surrounding rock,reduce the damage of dynamic load to anchor solid,and enhance the stability of anchoring bearing structure.(6)Based on the principle of full-length anchoring and the evaluation of the supporting effect of the roadway surrounding rock,the full-length anchoring method is applied to the roadway with strong dynamic load.Through the comparison and analysis of the test area and the original supporting section,the monitoring of surrounding rock deformation,drilling and anchor cable axial force are carried out.It is concluded that fulllength anchoring can effectively control the deformation of surrounding rock and maintain the stability of the anchor cable,which greatly reduces the probability of anchor cable failure under the action of strong dynamic load.The field practice shows that the full-length prestressed anchorage technology has obvious advantages in the control of roadway surrounding rock under strong dynamic load,and the top and bottom moving amount is 56～68 mm and the two sides moving amount is 74～90 mm without full length anchorage.In the full-length anchorage section,the drift of the top and bottom is 20～27mm and the drift of the side is 37～46 mm.After the full-length anchoring method,the deformation of the top and bottom of the surrounding rock is reduced by 36 mm～41 mm,and the deformation of the side is reduced by 37 mm～44 mm.Figure [116] Table [15] Reference [187]... |
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