Roof Deformation Law And Separation Analysis System Development Of Deep Mine Roadway With Strong Mine Pressure In Hulusu Mine

The complexity of deep mine mining environment and the rapid growth of stress have brought new challenges to roadway roof support.The previous theory of shallow mining is no longer fully applicable,especially the cognition and numerical prediction of roadway roof deformation and separation law,which greatly affects the support concept and parameter design.Therefore,it is necessary to master and study the deformation law of roadway roof and the principle of separation under the condition of strong mine pressure in deep mine.Based on the actual engineering background of 21205 auxiliary haulage roadway in Hulusu Mine,this thesis focuses on the key problems such as the deformation characteristics of roadway roof,the principle of roof separation,the determination of roof separation position and the calculation of critical value of roof separation.Through field investigation,theoretical analysis,numerical simulation,software calculation and engineering practice,the deformation law of roadway roof and the principle of separation under the condition of strong mine pressure in deep well are studied.The main results are as follows :(1)It is clear that roof separation is an important form of roadway roof deformation,which can be used as an important index to evaluate the stability of roadway roof.It is pointed out that the roof abscission layer can be divided into generalized roof abscission layer and narrow roof abscission layer.The generalized roof abscission layer refers to the relative displacement between a point in the roof rock layer and a point directly above it,including expansion deformation,elastic-plastic deformation,broken expansion deformation and other conditions,while the narrow roof abscission layer refers to the separation between the adjacent rock contact surfaces.(2)The causes of roof separation in roadway are analyzed.It is pointed out that roof separation can be divided into several categories : separation caused by shear and tensile failure of rock structure,separation caused by different deflection of rock stratum,separation caused by high level stress,separation caused by upper strength of rock stratum interface less than lower strength,and separation caused by geological conditions of rock stratum such as fault,fold,fracture and water seepage.(3)The key influencing factors of roadway roof separation are determined.In-situ stress,mechanical properties of surrounding rock,structure of surrounding rock,bolt reinforcement parameters,roadway section and coal pillar size are the main factors affecting the roof separation of roadway.Numerical simulation experiments show that vertical stress,horizontal stress,elastic modulus,cohesion and roadway width have a certain degree of influence on the separation of surrounding rock.In addition,the roof separation has different characteristics in different stages of mining activities.Among them,the size of the separation layer changes more violently during the roadway excavation,and the range in the horizontal direction is larger.During the pre-mining period after tunneling,the bed separation is relatively stable,mainly affected by the time effect,and the bed separation position gradually shifts to the inside of the soft rock layer.During the mining period,the increase of the size of the separation layer is more intense,and the separation layer is larger.Numerical simulation experiments support the above conclusions.(4)The process of judging the position of roof separation by load condition,span condition and deflection condition is deduced by the theory of ’key stratum ’.Based on the bending theory of elastic beam and the mechanical model of roof considering bolt and horizontal stress factors,the calculation formulas of elastic critical value and instability critical value of roof are derived.(5)Based on the above theory,a system for determining the position of roof separation and calculating the critical value of roof elasticity and the critical value of instability is developed and applied to the 21205 auxiliary roadway of Hulusu Mine.The results of the system analysis show that the 21205 auxiliary transport roadway in Hulusu Mine has the conditions for the separation of the layers at the HB8 and HB12 borehole measuring points.The elastic critical values of the two points are 17 mm and22 mm,respectively,and the instability critical values are 44 mm and 46 mm,respectively.The borehole spying shows that the separation of the two points is within10 mm,which is less than the elastic critical value,which proves that the current roadway stability is good.