Study On Instability Mechanism And Stability Control Of Large Deformation Roadway In Deep Surrounding Rock

As the country's economic development continues to increase the demand for resources,shallow resources are rapidly depleted,and most mining areas have entered the depth of the K-level mining.The large depth of the road makes the surrounding rock of the roadway mostly in the post-peak stage,and the overall performance of nonlinear large deformation characteristics seriously affects the safety of mine production.At present,some research results have been obtained in the instability mechanism and stability control of the surrounding rock roadway.However,there are still some limitations in the engineering practice.Therefore,the instability mechanism of the large deformation roadway in the surrounding rock is analyzed in depth.Strong stability control technology is of great significance.In view of this,this paper is based on the Deep Earth Mechanics and Underground Engineering National Key Laboratory Fund Project(SKLGDUEK1820)“Study on the evolution and stability control of surrounding rock structure of deep roadway covering the post-peak large deformation process”,to Shanxi Coal Transportation and Marketing Group Xinwang Coal Mine 3#coal return wind alley is the engineering background,using field research,theoretical analysis,numerical simulation,field industrial test research methods.The damage characteristics of the large deformation roadway behind the deep peak are summarized.The instability mechanism of the surrounding rock of the roadway is discussed.The stability control technology of the large deformation roadway with large adaptability is proposed and applied to guide the on-site support.There are a few of the things that this article does:1.Through field observation and collection of mine data,the roadway layout of the 3#coal return air main road of Xinwang Coal Industry Co.,Ltd.,the hydrogeological conditions of the roadway,the distribution characteristics of surrounding rock fissures,the ground stress and the mechanical parameters of surrounding rock mechanics are obtained.information.2.Through on-the-spot observation,it is summarized that the damage characteristics of the large deformation roadway in the deep rock after the deep peak include:(1)the initial deformation of the surrounding rock is large and the deformation duration is long;(2)the surrounding rock deformation shows obvious timeliness;(3)The surrounding rock of the top and bottom of the roadway has nonlinear deformation as a whole;(4)the sensitivity of surrounding rock is enhanced;(5)the damage of the roadway support structure is severe.The factors affecting roadway damage can be divided into two categories:internal and external factors;internal factors mainly refer to the nature of the surrounding rock mass,while external factors include ground stress,supporting structure,support mode and support timing,and groundwater and underground heat.3.After comprehensive analysis of roadway failure characteristics and influencing factors,the instability mechanism of roadway is obtained.It is considered that the strength of the surrounding rock is low,the sensitivity is high,and the high ground stress is the root cause.Support structure,support method and support Timing and geological environmental factors play a catalytic role.The instability mechanism of surrounding rock in different deformation stages of deep deformation roadway is analyzed,and the stability conditions of surrounding rock in each deformation stage are obtained.4.The thesis analyzed the character of extrusion damage of surrounding rock in deep roadway with Coulomb-Mohr yield criterion,and studied the elastoplastic range and its stress distribution.For plastic stress distribution,it studied that after the strength of rock mass is greater than ultimate strength ofrock mass,it will be linearly reduced.it is concluded that in this case the radius of plastic zone of surrounding rock raised 30%than the ideal elastic-plastic radius of plastic zone.5.Based on the surrounding rock-support wave balance law,combined with arch-coupling support theory and thick anchor plate control theory,the paper proposes"the shallow surrounding rock stress recovery,the post-peak rock mass consolidation repair,the dynamic superposition overall control,and the deep and shallow bearing common"Four"surrounding rock control principle,the establishment of the"intensive high-strength anchor+self-propelled grouting long anchor"as the main support,"high-strength anti-crack concrete spray layer+deep shallow zone rigid-flexible coupling grouting"as an auxiliary Supporting multi-level deep-shallow coupling integral support system,analyzing the surrounding rock control mechanism of each supporting structure,and exploring the influence of support on the bearing capacity of surrounding rock;comprehensively evaluate the support effect,select the optimal support parameter combination,and obtain the influence degree of each support parameter on the stability of surrounding rock;6.Through the FLAC~3DD numerical simulation,the roadway mechanics model is established.The original support scheme of the roadway and the multi-level integral support scheme of distribution characteristics of the surrounding rock stress field,displacement field and plastic zone of the roadway are compared and analyzed,and the rationality of the support scheme is demonstrated.7.Based on the above research results,the support scheme is applied to the surrounding rock support of the 3#coal return wind roadway in Xinwang Mine.After 45 days of roadway formation,the surrounding rock deformation tends to be stable,and the convergence rate of surrounding rock falls below 1.2mm/d.The maximum deformation of the top plate is 60mm,the maximum deformation of the two gangs is 36mm,the maximum deformation of the bottom plate is 21mm,the amount of surrounding rock is significantly reduced,and the supporting structure is also free of cracking and damage.The effective control of the rock deformation roadway proves the feasibility of the control technology.