Study On Mechanism And Treatment Of Floor Heave In Near-Falut Roadway

Underground faults,as a common geological structure,are widely distributed in the mine field.With the continuous development of mining engineering,the roadway inevitably interacts with the surrounding faults in the process of roadway design,layout and daily mining activities,which makes the surrounding rock of roadway floor affected by faults and other geological structures.as a result,the difficulty of support is greatly increased.The phenomenon of floor heave not only affects the safety of coal mine production,but also will be more serious with the trend of coal mining,so the research on the mechanism and treatment countermeasures of floor heave in near-fault roadway is of great significance to the normal operation of coal mine and the safety of employees.Based on the theories of elasticity,material mechanics,mine pressure and control,and by means of numerical simulation,mechanical analysis and XRD phase analysis experiment,this paper analyzes the surrounding rock variation characteristics of the main transport trough and faults in Wanli No.1 Coal Mine,based on the theories of elasticity,material mechanics,mine pressure and control,and by means of numerical simulation,mechanical analysis and XRD phase analysis experiments,the paper takes the surrounding rock and the whole fault as the research object,based on the theories of elasticity,material mechanics,mine pressure and control,etc.In addition,the characteristic distribution analysis,mechanical model,mechanical analysis and influence factor analysis of the floor strata are carried out,and the research objectives are deeply analyzed and studied combined with the relevant research results of predecessors.in this paper,the floor heave mechanism is summarized,two floor heave prevention schemes are put forward,and the stability and rationality of the support model are verified,and a good floor heave treatment effect is obtained.The main research results of this paper are as follows:(1)Through on-site investigation and numerical simulation,the stress environment and surrounding rock deformation characteristics of near-fault roadway are analyzed,and the characteristic distribution of floor strata is analyzed.it is concluded that 10 m is the critical interval of non-symmetrical failure of roadway surrounding rock under the influence of fault,and the type of floor heave is extruded and flowing floor heave.(2)Based on the basic theories of material mechanics and elasticity,the mechanical model of horizontal beam of floor without support is established by using the mechanical knowledge of beam theory.Through the mechanical analysis of the floor of rectangular roadway with main running groove under the influence of fault,the deflection formula is improved.Through the analysis of a numerical example,it is concluded that different factors such as stress,elastic modulus,floor span,bolt length and bolt pretightening force have different effects on the floor heave of the near-fault roadway and the mechanical analytical deflection of the near-fault trough floor.(3)Through indoor XRD experiments and geological data,it is found that the floor strata are softened by water.Combined with the above research,it is considered that the cause of the floor heave is due to the extrusion flow of the bottom plate and the softening of the bottom plate in the presence of water.(4)Based on the two support schemes for the treatment of floor heave proposed by the above research,through the previous experience and theoretical analysis and the structural stability discrimination equation of floor bolt-concrete reverse arch combination,the stress environment and surrounding rock deformation characteristics are analyzed.The feasibility of the combination of floor bolt-notch and floor bolt-concrete reverse arch support is verified respectively,and compared with the surrounding rock deformation of near-fault roadway without support.The bottom heave volume is reduced by 70.2% and 92.1% respectively,and a good treatment effect has been achieved,which provides a reference for the ultimate goal of controlling the surrounding rock of the 42303 main trench roadway and controlling the floor heave in Wanli No.1 Coal Mine.