Study On Mechanical Properties Of Caulking Material Of Shield Tunnel Segments

With the advancement of the economy and the development of comprehensive national strength,a large number of shield tunnels have emerged in China in recent years,and shield construction has become a trend in the development of tunnel construction.The waterproofing design of domestic shield tunnel is based on self-waterproofing of tube piece,with emphasis on seam waterproofing.Meanwhile,waterproofing treatment of special parts(such as bolt holes)is considered to form a complete waterproofing system.Caulking waterproofing has always played an auxiliary role in waterproofing in the development history of shield tunnels.As the waterproof innermost waterproof structure of shield tunnel joints,this paper uses caulking as a waterproof measure capable of independently resisting certain water pressure,and studies its mechanical properties.The main research results are as follows:(1)Various general caulking materials were selected for mechanical performance test.Relevant parameter indexes were determined according to the test results,and the materials were classified.Finally,representative materials were selected to study the mechanical properties of the caulking waterproof layer.(2)The mechanism of caulking bonding was studied.According to the bonding mechanism,ABAQUS numerical analysis software was used to analyze the static analysis of caulking waterproofing,and the results of related material parameter indexes on the force of caulking waterproof layer were investigated.And compare the indoor test and numerical results to verify the accuracy of the numerical calculation.(3)This paper investigates the possible adverse loads on the seam waterproof structure of shield tunnel in the course of tunnel operation.The train vibration loads and aerodynamic loads on the seam material are calculated by using the calculation software MIDAS and FLUENT,so as to study the mechanical characteristics of the seam waterproof layer under dynamic loads.(4)Combined with the actual project,the hydraulic test of the caulking waterproof layer is carried out under the action of static force and power,and the waterproof ability of the caulking waterproof layer is explored,which provides guidance for the waterproof design and operation and maintenance of the caulking.Through the study of waterproofing mechanics characteristics of seam,it is proved that seam waterproofing of deep-buried large cross-section shield tunnel can be used as an independent waterproofing measure and withstand certain water pressure,which provides reference for waterproofing design,operation and maintenance of seam of shield tunnel.