| There are various types of cracking disease in tunnel lining,one of the most common forms is crack,which not only endangers the lining structure,but also affects the safety of the tunnel.Through the investigation of tunnel lining repair methods,in view of the deficiency of the existing repair methods,the method of repairing the cracking lining by the steel plate and the short anchor is put forward to form plate-short anchor assembly structure.And the plate-short anchor assembly structure has the characteristics of convenient prefabrication,strong anchorage connection,tight fitting of steel plate and cracking lining,small occupancy space,convenient construction,no damage to waterproof layer,and the carrying capacity can be quickly promoted.At present,there are many unidentified mechanical mechanisms for the plate-short anchor assembly structure.After comprehensively comparing the research methods of previous scholars,the reinforced concrete large eccentric loading component was used to simulate the mechanical state of the tunnel vault positions.This Thesis relies on project” Mechanical Mechanism of Rapid Repair Assembly Structure in Existed Transportation Tunnel Lining Cracking”(No.51038009)of National Natural Science Foundation.By using the method of experiment of component,the mechanical mechanism of tensile fracture of different degree of longitudinal crack in the vault,which was repaired by steel plate and the short anchor has been studied.The main achievements and conclusions are as follows:(1)Through the analysis of the mechanical state of the tunnel lining,the plate-short anchor assembly structure was formed by steel plate and short anchor repair cracking lining,Which can be simplified as the study of the mechanical properties of the reinforced concrete large eccentric loading component repaired by steel plate and short anchor.According to the mechanical state of large eccentric compression loading,a set of complete internal force system is designed for the eccentric compression loading device for the test of tunnel lining components.(2)After the cracking occurred on component,the carrying capacity of the component decreases obviously,and the carrying capacity of different cracking degree has been decreased different.The carrying capacity of the plate-short anchor assembly structure has been significantly improved.The ultimate carrying capacity of component with cracked depth of 30% thickness was increased by 18.18%,the ultimate carrying capacity of component with cracked depth of 50% thickness was increased by 16.28%,and the ultimate carrying capacity of component with cracked depth of 70% thickness was increased by 16.67% after repair.(3)After the cracking occurred on component,the cracks will continue to develop along with the increase of load,and neutral axial move to the compression zone of concrete,and after the compressive stress reaches the limit stress,the component was destroyed.The assembly structure of steel plate and short anchor can effectively reduce the development of cracks,while the moving speed of the neutral axis slows down,and the compressive properties of concrete can be more fully played.(4)As a component part connecting steel plates and components,short anchors are subjected to drawing and shearing at the same time.And the short anchor away from the crack position is subjected to greater shear force,while the short anchor near the crack is subjected to greater pulling force.Steel plate is the main part to bear tensile stress in assembly structure,stress concentration will occur in the position of steel plate drilling hole,mainly expressed as compressive stress. |
