| With the mining of underground coal,there are a lot of surface deformation areas.The steel box module structure system is composed of several adjacent steel boxes connected,with a natural "deformation joint",in response to the national double carbon target building upgrade,but also has the advantages of flexibility and reusability,which is conducive to solving the increasingly serious contradiction between human and land resources in the surface deformation area and rising relocation costs and other key problems.In this thesis,the influence law of surface deformation on the steel box module structure is studied by the finite element simulation method.By analyzing the similarities and differences between the steel box module structure and the traditional steel frame,the influence law of module connection performance,column foot connection performance and foundation form on the deformation resistance of the steel box module is studied.Finally,the maximum deformation value of the steel box module structure is proposed based on the finite element results.This thesis provides reference for structural design of steel box module in goaf.First,a reference model of the interaction of steel box module structure was established,and five kinds of surface deformation effects were determined.The analysis was carried out by establishing 32 finite element models.The main conclusions are as follows:(1)As the axial stiffness of the horizontal connection decreases,the anti deformation performance first improves and then decreases.When the axial stiffness of the horizontal connection is 1/125 of the horizontal tensile stiffness of the floor beam,the anti compression deformation ability is improved;(2)The maximum stress position gradually shifts from the edge column foot to the center column foot as the horizontal connection stiffness decreases,and ultimately exceeds the safe bearing capacity at the center column position;(3)As the axial stiffness of the horizontal connection decreases,the additional stress,bending moment,and shear force at the horizontal nodes between the steel box modules gradually increase;(4)The stress and internal force at horizontal nodes gradually decrease with the decrease of horizontal bending stiffness and shear stiffness.Secondly,on the basis of the reference model,165 finite element models were established to carry out the analysis of inter-module connection stiffness parameters and study the influence rule of inter-module connection stiffness anti-deformation performance.The main conclusions are as follows:(1)As the axial stiffness of the horizontal connection decreases,the anti deformation performance first improves and then decreases.When the axial stiffness of the horizontal connection is 1/125 of the horizontal tensile stiffness of the floor beam,the anti compression deformation ability is improved;(2)The maximum stress position gradually shifts from the edge column foot to the center column foot as the horizontal connection stiffness decreases,and ultimately exceeds the safe bearing capacity at the center column position;(3)As the axial stiffness of the horizontal connection decreases,the additional stress,bending moment,and shear force at the horizontal nodes between the steel box modules gradually increase;(4)The stress and internal force at horizontal nodes gradually decrease with the decrease of horizontal bending stiffness and shear stiffness.Thirdly,50 finite element models were established to carry out the analysis of column foot connection stiffness and foundation form parameters.The main conclusions are as follows:(1)When using a strip foundation with a width of 1.5m and a foundation buried depth of 1.5m,and a raft foundation with a thickness greater than 0.5m,it can withstand five types of surface deformation with extreme damage levels,and the structural deformation resistance performance is rapidly improved;(2)As the stiffness of the column base connection decreases,the anti deformation performance of the steel box module structure gradually improves.When using a semi rigid column base with a bending stiffness of 1/5 of the column bending stiffness,it can withstand extreme damage levels of inclined deformation,positive curvature deformation,moderate damage levels of tensile deformation,compression deformation,and negative curvature deformation;(3)As the stiffness of the column base connection decreases,the additional bending moment and shear force at the horizontal node position of the edge rapidly increase;(4)Improving the foundation stiffness is the most effective way to improve the deformation resistance performance of steel box modules.Finally,based on the results of finite element parameter analysis,grey correlation method was used to carry out weight analysis and put forward anti-deformation design suggestions:(1)The buried depth of foundation,the joint stiffness of column foot and the horizontal axial stiffness are the biggest influencing factors on the maximum stress and bending moment index of the structure,which should be given priority in the structural design;(2)Strengthening foundation stiffness is the most effective way to improve the deformation resistance of steel box module.Strip foundation or raft foundation with higher foundation stiffness can be used to resist surface deformation;(3)When the foundation burial depth can satisfy the foundation bearing capacity under the vertical load of the structure,the independent foundation burial depth should be reduced as far as possible;(4)The stiffness connection form of column feet plays an important role in the deformation resistance of steel box module structure,so it is recommended to use semi-rigid connection column feet;(5)In the anti-deformation design of goaf buildings,the horizontal axial and flexo-shear stiffness can be properly weakened to ensure the vertical connection performance in limited space,so as to improve the anti-deformation ability of steel box modules.This thesis includes 83 figures,40 tables and 84 references. |
