Study On Mechanical Properties Of Composite Structure Formed By Repairing Rhegma Lining Of Plate Members

Lining rhegma is a common disease in the tunnel,the lining rhegma will greatly affect the overall stability of the tunnel,thus affecting the operational safety of the tunnel.At present,scholars at home and abroad have a lot of research on tunnel diseases,there are many mature technologies for different diseases,such as reinforcement with arch surround,anchor reinforcement,anchor-shotcrete reinforcement etc.However,there are a lot of reinforcement measures can not be implemented because of many objective conditions,such as headroom,complex process,etc.Plate structure reinforcement is to take full advantage of the self-bearing capacity of the lining.On the surface of concrete,steel and other high strength materials are strengthened,and the composite structure is combined with the existing concrete,improve the structural stress.It has a short installation time,can be prefabricated and other characteristics,can quickly repair the tunnel But at present,this method is applied to the bridge reinforcement,the stress characteristics of the tunnel is not clear.In this thesis,the model test and numerical simulation are used to study the mechanical properties of composite structures.The main results of this thesis are as follows:When the vault damage is 30%,50%and 70%,the safety is reduced by 43.2%,51.3%and 59.4%compared with the intact condition.When the lining cracks,the safety is reduced by 64.8%.Therefore,the lining cracking will lead to the decrease of bearing capacity and the change of failure shape.After the repair of the arch damage by the plate type member,the plate member can share part of the axial force and reduce the axial force of the lining so that the safety is increased by 19%,22.2%and 26.6%.After the cracks are repaired,the lining bending moment is reduced by 35.1%,and the development of the restrained crack increases the safety of the lining by 46.2%.The plate member reinforcement crack lining,lining structure and plate components respectively bear the internal force combination structure of 60%?80%and 40%?20%,the main function of the plate member is improve the stress state of lining,and the lining is the main force.When the plate member is too strong,the safety factor of the composite structure is too large,and the lining will be damaged by the other parts exceeding the ultimate carrying capacity,resulting in the waste of material and the difficulty of construction.The appropriate plate member stiffness should be determined according to the degree of crack.