Study On Mechanical Support Structure Of Goaf Roadway

Currently,coal and other mineral resources still occupy an important position in China.With the continuous deepening of coal mining and the advancement of mining methods,the application of cut-top and pressure-relief mining with no coal pillars and leaving goaf along the airway is becoming more and more widespread.However,the corresponding support technology for the airway along the goaf of thick coal seams is a difficult problem.For the airway along the goaf of thick coal seams cut by the method of cut-top and pressure-relief mining,the support of the support pillar near the airway is subject to greater roof pressure,and the support pillar is severely damaged.The collapse impact and lateral stress of the gangue in the goaf on the gangue-blocking device are huge,and the gangue-blocking structure is easily bent and damaged towards the airway,resulting in damage to the airway and causing personnel and property losses.Therefore,a reliable structure with large load-bearing capacity and able to take into account the gangue-blocking and supporting of the airway is needed.This thesis proposes a force transmission gangue-blocking support scheme with a joint support structure of the support pillar and the gangue-blocking device.The structure of the scheme consists of the support part and the force transmission gangue-blocking device.The design of the support is a four-pillar design,which is more stable than the traditional two-pillar design.Each pillar can be controlled individually through a hydraulic device or maintained at a constant pressure support according to the top plate pressure,which can dynamically adjust the top plate posture to adapt to the unbalanced dynamic load caused by surrounding rock movement,achieving pressure support.At the same time,the force transmission device can share the load of the gangue-blocking device to the support,consider the gangue-blocking and supporting of the top plate as a whole,and achieve joint protection of the gangue-blocking and the roof,solving the problem of U-shaped steel bending failure of the gangue-blocking device under heavy load conditions of medium-thick coal seams.Combined with the constant resistance anchor rod in the airway and the single-body support on the mining side,it can jointly maintain the stability of the airway.This thesis aims to improve the joint support gangue-blocking scheme and optimize its structure.Firstly,according to the movement characteristics of the top and bottom of the cut-top airway at home and abroad and the pressure condition of the surrounding rock of the thick coal seam in the top airway,the stress of the surrounding rock and the support system is coupled,and the corresponding relationship between the surrounding rock pressure and the working resistance of the oblique brace support is obtained.Then,a two-dimensional mechanical model of the joint force of the support in different cut-top stages is established,and the maximum support force required during the goaf retention process is analyzed,providing a theoretical basis for the force transmission gangueblocking support scheme of the joint support structure.Then,a complete design scheme of the four-pillar unit support is proposed,and the parameter design and calculation of the frame body and the force transmission device are completed.The design of the main components,such as the top plate,double telescopic column,and bottom plate,is completed,and the three-dimensional models of each part are established in Solid Works and assembled to obtain the overall model.Finally,the support is analyzed kinematically in ADAMS to verify the motion relationship of the support components,and the main component simulation and load simulation analysis of the overall support under four working conditions are carried out in ANSYS to verify the rationality of the main components and the overall load under load.