A Research On The Impact Of The Tunnel Lining Cracing On The Structure Force Performance

The crack of tunnel lining is one of the most common diseases of tunnel structure.The presence of cracks changes the stress state of the lining structure and adversely affects the safety of the lining structure.For this reason,based on accessing to the current status of a large number of tunnel lining cracks,the earth studies on the impact of the tunnel lining cracing on the structure force performance.The main work content and results are as follows.(1)Based on the statistics of the current situation of a large number of tunnel lining cracks,revealing the distribution rules of different types of cracks by consulting literature.(2)It reveals the stress characteristics,deformation law and crack characteristics of the lining structure under normal conditions.The results show that,when the lining structure has no cracks,the surrounding rock pressure,the internal force and deformation of the lining structure are symmetrically distributed around the axis of symmetry of the lining structure.The surrounding rock pressure at the lining side wall is the largest,the contact pressure of the invert arch and the vault is relatively small.The invert arch is the weakest part of the lining structure,followed by the vault and the left and right arches.(3)The results show that,under the same load level,the contact pressure between the dome and the inverting arch of the lining structure with cracks is reduced,and the contact pressure at the side wall is increased.When the crack is located in different parts of the lining,the change of contact pressure at the crack is the most significant,and as the number of cracks increases,the change is greater.(4)The influence of lining crack on structural force and deformation is analyzed.When there are cracks in the lining,the internal force of the lining is redistributed,and the bending moment at the crack is significantly reduced.Cracks cause a reduction in the bending moment of the lining in a certain area around it.Cracks in different locations have different influence ranges,but for the same position,as the number of cracks increases,the influence range increases.In addition,the lining crack will increase the deformation of the entire lining,and the change of displacement at the crack is the most obvious.(5)The influence of lining crack on the cracking law of lining structure is discussed.he results show that the existence of cracks will affect the load,lining stress and crack depth when cracking various parts of the lining.The cracks in the inverting arch will cause the internal force of the lining of the arch to become larger.The crack in the arch will cause the internal force of the lining of the invert to become larger.The crack in the side wall will cause the internal force of the lining of the arch to become smaller.