Development And Application Of Physical Simulation System For Dynamic Shock In Deep Roadway

With the gradual depletion of shallow coal resources,coal mining to deep development has become an inevitable trend.With the continuous increase of coal mining depth,the ground stress is gradually increasing,and the geological structure is more complex.Under the common influence of a variety of adverse factors,deep roadway disasters occur frequently.Power accidents such as rock burst and mine earthquake account for most of them,which seriously affect the safe and efficient mining of coal.Physical simulation test is an important means to study the occurrence mechanism and control method of deep roadway dynamic impact phenomenon,which has the advantages of simulating the occurrence process of dynamic impact phenomenon and realizing multi-parameter data acquisition of surrounding rock.In this paper,the conditions that are easy to lead to dynamic disasters are obtained through numerical simulation,and the research and development requirements of the deep roadway dynamic impact physical simulation system with "high stress equalization-boundary energy storage" as the core loading is defined.The design concept of balanced loading-boundary energy storage is proposed,which provides guidance for the design of the deep roadway dynamic impact physical simulation test system.A physical simulation test system for deep roadway dynamic impact was developed,and the reliability verification test of the system was carried out,which provided instrumental support for the research on the occurrence mechanism and prevention of deep roadway dynamic impact phenomenon.The main research work is as follows.(1)Numerical simulation of dynamic load disturbance in deep roadwayBased on the engineering background of 7301 working face track channeling in 1000km deep well--Zhaolou Coal Mine,the numerical calculation model and quantitative evaluation index of deep roadway dynamic disturbance were established,and the influence law of different stress levels and disturbance loads on the energy,stress and convergence deformation of roadway surrounding rock was studied.The results show that with the gradual increase of ground stress,the internal stress and energy accumulation degree of roadway surrounding rock increase gradually.When the surrounding rock is disturbed,the increment of surrounding rock energy and stress presents a nonlinear growth trend with the increase of ground stress.The deep high stress environment is more likely to lead to the accumulation of surrounding rock energy and the occurrence of impact phenomenon.(2)Design of deep roadway dynamic impact physical simulation systemAiming at creating a high-stress environment and realizing the boundary energy storage of the model body,the balanced loading device and boundary energy storage device were designed from two aspects of the experimental loading system and reaction frame system to meet the requirements of high stress application and energy storage loading at the boundary of the model body.By simulating different reaction frame materials and different column forms,The layout of the reaction frame system made of 690D special steel and the "round outside and square inside" form of the reaction frame system are determined.The system can meet the requirements of high ground stress environment construction,model body boundary energy storage,Three-direction hexahedral true triaxial loading and ensure the stable development of the test process,which provides a reference and basis for the development of deep roadway dynamic impact system.(3)Development of physical simulation system for deep roadway dynamic impactA dynamic impact simulation system for deep roadway with a size of 4m×3.2m×4.2m is developed.The system is composed of reaction frame system,loading system,hydraulic and control system,and can carry out tests on the model body with a maximum size of 0.85m×0.85m×1.6m(width × height × length).The top is loaded by boundary energy storage device,the stress loading range is 0～20MPa,the boundary energy storage size is 0～9×105J,and the boundary energy storage loading rate is 0～3000J/s.The confining pressure is provided by a balanced loading device.The range of confining pressure that can be loaded is 0～10MPa.The total hydraulic power of hydraulic and control system is 107kW.(4)Hierarchical loading test of deep roadway dynamic shock physical simulation systemThe gradient hierarchical loading test was carried out with this system,and the difference between the designed loading path and the actual loading path was compared,and the threedimensional stable loading performance of the system was verified.The effect of force transfer in different parts of the model body and the stress distribution in different layers were analyzed.The maximum difference of stress distribution in the same horizontal plane was 0.25MPa and the minimum was 0.095MPa.As the distance from the loading surface gradually increases,the stress on it gradually decreases.The stress transfer effect of the measuring points in the middle of the model body is better than that of the measuring points at the boundary of the model body.