Research On Mechanical Analysis And Stability Control Technology Of Surrounding Rock Bearing Structure Of Deep Roadway

With the increase of coal mining depth,the conditions for the occurrence of roadway surrounding rock and the degree of deformation and destruction are becoming more and more complicated.The control of deep roadway surrounding rock has become one of the problems faced by the coal industry in our country.Especially under the conditions of large mining depths,the three high problems(high ground temperature,high ground stress,high permeability pressure)and strong mining disturbances cause serious nonlinear large deformations in the surrounding rock of the roadway.To control the stability of the roadway,it is necessary to control the stability of the roadway.The bearing structure of the surrounding rock is divided to clarify the deformation and failure characteristics of the surrounding rock of the roadway.At the same time,due to the increase in coal mining depth,the single bearing capacity of bolts needs to be continuously strengthened.As an important type of bolt,fully anchored bolt have been widely used in roadway support.The distribution law of rod stress is an important content in anchoring and supporting technology.Therefore,this paper analyzes the deformation and failure characteristics of the surrounding rock of the roadway and the evolution of the surrounding rock bearing layer according to the stress change trend of the surrounding rock of the roadway and the evolution of the surrounding rock bearing layer,so as to further divide the bearing structure of the surrounding rock of the roadway;based on the surface deformation of the surrounding rock and the deep rock,establish the surrounding rock-anchor mechanical model,clarify the relationship between the shear stress of the fully anchored bolt and the surrounding rock deformation,reveal the stress distribution of the fully anchored bolt,and reflect the fully anchored bolt in the surrounding rock through FLAC3D numerical simulation on the basis of the aforementioned fully anchored bolt stress distribution and stress field distribution characteristics,combined with the evolution of the surrounding rock bearing layer of the roadway,the original support of the first horizontal return air gate(thousand-meter deep roadway)in Xinhu Coal Mine The optimal design of the support plan is carried out,and the rationality of the support plan is verified by the establishment of a "layer-double arch" surrounding rock mechanical bearing structure through theoretical analysis.Finally,FLAC3D numerical simulation and on-site industrial tests are used to further verify the reliability of the plan.The main research work is as follows:(1)Research on the division of the bearing structure and the deformation and failure characteristics of the surrounding rock of the roadway.According to the stress change trend of the surrounding rock of the roadway and the strength change of the surrounding rock,the secondary bearing structure of the surrounding rock is divided according to the full stress-strain curve of the four-line segment of the roadway into a coupled bearing layer of "flowing layer-plastic softening layer-plastic hardening layer-elastic layer",and adopting FLAC3D numerical simulation analyzes the deformation law of the surrounding rock of the roadway and its relationship with the support resistance.By fitting a large amount of simulation data,it is obtained under different surrounding rock conditions(based on the different surrounding rock lithology,the surrounding rock of the roadway is divided into soft rock,Medium-hard rock,hard rock)The deformation law of the surrounding rock of the roadway at different locations is compared with the deformation law of the roadway surrounding rock derived from the theory to verify the rationality of the theoretical analysis.(2)Numerical simulation study on the stress distribution law and stress field distribution characteristics of fully anchored bolt.Based on the principle of overall coordinated deformation,combined with the relationship between the deformation characteristics of the roadway surrounding rock and the support resistance,the surrounding rock-bolt mechanical model is established,and the fully anchored bolt shear stress-surrounding rock deformation constitutive equation is constructed,thereby revealing the fully anchored bolt.The stress distribution law of anchor bolts and the analysis of the influence of related anchoring parameters on the stress distribution law of fully anchored bolt.FLAC3D numerical simulation is used to verify the reliability of the aforementioned stress distribution law of fully anchored bolt,and the fully anchored bolt in the surrounding rock to study the stress distribution characteristics of the fully anchored bolt support and analyze the main characteristics of the stress field distribution and related influencing factors.(3)Optimization and design of roadway support in one-kilometer deep mine.Based on the layered evolution law of the bearing layer of the surrounding rock of the roadway,combined with the actual geological conditions,the range of the plastic bearing area of the surrounding rock of the northern return airflow of the mine is determined.Based on the obtained plastic bearing range,combined with the stress distribution of the fully anchored bolt,the conclusions obtained from the study of the law and the distribution of the stress field are used to optimize the design of the support for the return air crosscut of the mine,and the corresponding joint support scheme is proposed.(4)The establishment of the bearing mechanical model of the surrounding rock-supporting structure of the one-kilometer-deep mine roadway.In order to verify the reliability of the joint support scheme,a mechanical model of the "layer-double arch" bearing structure was established based on the actual occurrence of a horizontal return air crosscut in Xinhu Coal Mine,Under the ultimate equilibrium condition,the force analysis is performed to obtain the ultimate bearing strength calculation formula of the bearing structure,and the ultimate bearing strength of the "layer-double arch"bearing structure formed by the return air roadway is checked.Finally,FLAC3D numerical simulation and on-site industrial tests are used to verify the reliability of the proposed joint support scheme.Figure 66 table 8 reference 105...