Characteristic Analysis And Stability Evaluation Of Anchoring Bearing Structure Of Surrounding Rock In Rectangular Roadway

Traditional theory believes that in the design of roadway bolt support,the bolt anchoring section must extend beyond the loose range of the surrounding rock to play a role of bolt support.However,in the process of roadway support,the bolt is not only in Supporting force is provided on the surface of the roadway.The essence is the coupling effect of the anchor rod and the surrounding rock to form a bearing structure with a certain strength.The bearing structure improves the rigidity and strength of the surrounding rock,fully exerts the self-supporting effect of the surrounding rock,and meets the deformation requirements,Plays a vital role in the stability of surrounding rock,but the current support design method is separated from the surrounding rock,the structural characteristics of the bolt and the surrounding rock are not well described,and the methods and methods for studying the anchor bearing structure are not obtained.Give full play to the phenomenon of insufficient or even on-site support strength.Therefore,this article systematically describes the theory of bolt support,and on the basis of the predecessors,analyzes the supporting performance of the anchor bearing structure,based on the elastoplastic theory to obtain the physical and mechanical parameters that affect the rigidity and strength of the anchor bearing structure,and uses the structural mechanics Based on the design theory,a mechanical model of the rectangular roadway bearing structure is established,and its mechanical and deformation characteristics are analyzed.Based on the field industrial test based on the S1230 auxiliary transport flume of the Ningtiaota Mine in northern Shaanxi,a reasonable and optimized supporting scheme is proposed to verify the theory of this paper Rationality.The main research results of the paper are as follows:1.Analyzed the bolt support theory,the surrounding rock failure mechanism and the anchor bearing structure form,the coordinated deformation of the anchor rod and the surrounding rock is equivalent to the anchor bearing structure,which has evolved from a single anchor reinforcement to an integral reinforcement of the underground structure.The formation mechanism of the anchor bearing structure and the supporting forms of various roadway anchor bearing structures are analyzed,and the analytic solutions of the stiffness parameter and the strength parameter deformation are solved by the elastic-plastic theory analysis.The calculation example shows that after the anchor is strengthened,the internal rigidity and strength of the bearing structure change significantly,that is,the length of the anchor increases,the strength and strength of the structure increase;the spacing between the anchors increases,and the rigidity and strength of the structure decrease;the anchor As the shaft force increases,the structural strength and strength increase.2.Analyzed the failure mode of the rectangular roadway and showed that the cause of the failure of the anchor bearing structure is mainly related to its tensile strength and shear strength.The bolt support effect is equivalent to improve the mechanical parameters of the anchoring structure,and the anchor cable support effect is equivalent to a set of support forces.The structural mechanics design theory is used to establish a portal structure mechanical model for the rectangular tunnel after support and the solution is obtained.The structural internal force change diagram of the structure supported by the anchor rod and the structure supported by the anchor rod(cable)is obtained to obtain the internal force(including bending moment,axial force,shear force)and deformation distribution characteristics of the structure,and the internal force is obtained according to the calculation results Maximum position.According to the structural geometric displacement calculation equation and M-C criterion,the deformation and strength stability evaluation methods are proposed.The calculation example shows that the length of the anchor rod increases,the distance between the rows decreases,and the axial force of the anchor rod increases,the deformation of the surrounding rock decreases,the normal stress destruction coefficient,the shear stress destruction coefficient increases,and the stability of the surrounding rock improves.The joint support of poles(cables)can effectively ensure the stability of the surrounding rock of the roadway.3.Combined with the example of S1230 auxiliary transportation along channel project in Ningtiao Coal Mine,the original tunnel support effect was monitored,based on the anchor bearing structure mechanical model,the optimized support design and numerical simulation verification were carried out,and combined with the measured values,the two supports were compared.The reinforcement effect of the anchor rod under the protection condition,thereby improving the tunneling efficiency and economic benefit,and saving manpower and material resources.