Dynamic Characteristic Of Rope-Guided Hoisting System With Multiple Constraints

With the increase of coal demand,the scale of coal mining and coal mining depth increases year by year.The increased mining depth leads to more complex geological structure of underground rock stratum.Unstable and unsafe factors are also relatively increased,such as shaft wall cracking and even falling off.This increases the failure rate of rigid guide rail.As a result,the rigid guiding rail is more dependent on the stability of the rock lining than rope-guided rail.Therefore,China has increased the construction projects of rope-guided hoisting system under deep shafts in recent years.However,due to the structural limitations of the wire rope itself,the maximum depth of shaft is also limited to a certain extent.And rope guides are not tensioned enough with the increase of the well depth,resulting in insufficient lateral stiffness,thus causing large lateral displacement of conveyance and other problems.Therefore,it is of great engineering significance to study dynamic characteristics of rope-guided hoisting system in deep shafts,thereby restrain the lateral displacement of conveyance caused by insufficient tension,and realize the depth extension of rope-guided hoisting system to a ultra deep.Rope-guided hoisting system is taken as the research object,and dynamic characteristics of rope-guided hoisting system under four guiding ropes are carried out.Meanwhile,limiting factors and influence rules are obtained for the limited depth of shaft,and the maximum limit depth of shaft is found out.The problem of sparse matrix and loose boundary existing in traditional finite element continuum modeling method is solved under multiple constraints between guiding ropes and conveyance.Balanced method of horizontal torque caused by asymmetric constraints,and the strategy of restraining lateral displacement are given,which provides theoretical support for the mining and construction of ultra-deep shafts.Firstly,based on the lteral stiffness characteristics of rope guides,a lateral stiffness model of guiding rope under multi-point constraints is established by Newton’s force balance equation,and the minimum stiffness position of guiding rope under multi-point constraints was obtained.The minimum stiffness position is treated dimensionlessly.The influences of top tension,the number of constraint boundaries and the layout of guiding ropes on guiding rope stiffness are obtained.Based on static analysis,the maximum limiting value of rope-guided hoisting system in China was given under the given guiding rope density.Accordingly,suggestion of extending the well to the deep well is presented.Secondly,a fixed-quantity local variable length element model is proposed based on the advantages of fixed-quantity constant length element model and constant quantity continuous variable length element model.The average of finite element length is guaranteed to solve matrix sparse and boundary divergent in fixed number of continuous variable length element model.Simultaneously,this method ensures that constraints point between guide ropes and conveyance always staying on a node,thus ensuring the bending effect of guide rope shape and providing theoretical foundation for rope-guided hoisting system modeling with four rope guides.Thirdly,combined with the fixed-quantity local variable length element model,the lateral-longitudinal-torsional coupling dynamic model of four-rope guiding hoisting system is established based on the Lagrange equation with constraints.According to the excitation source of the hoisting system,the dynamic responses of the four-rope guiding hoisting system are obtained under various excitations.The dynamic response of conveyance guided by ropes is analyzed through an example,where the fundamental reason for the arrangement of east and west conveyance in China is revealed.The strategy and control range of weakening the torque response are given under the basis and method of adjusting the tension difference at the bottom of the guiding ropes,which provides a theoretical basis for multi-rope guiding hoisting system in the future.Finally,in order to obtain the lateral displacement restrain method of ultra-deep shafts,the principle of graph theory is used to design the configuration of deflection inhibition mechanism.When the deflection inhibition mechanism is used to increase a constraint in the middle of guide rope,lateral stiffness of guide rope is increased and lateral displacement of conveyance is descended.Meanwhile,the tension range at the bottom is provided to achieve the best amplitude inhibition effect.The maximum limit depth of the shaft can be reached under the dynamic condition of the analyzed ropeguided hoisting system when constraint is introduced in the middle length of guide rope.The extension of the rope-guided hoisting system is theoretically realized to the ultradeep distance.This thesis has 77 figures,19 tables,145 references.