Analysis Of Mechanical Characteristics Of Joints Of Integral Immersed Tube Tunnels

As an important part that determines the safety and service life of immersed tube tunnels,the joints of immersed tube tunnels have always been the focus of the scholars and civil engineers.The main objects of this paper are steel shear keys and GINA waterstops.The main function of the steel shear keys for pipe joints is to resist the shear failure of the joints during usage,and the GINA waterstops are to ensure the joints not leaking,which means good water tightness.Steel shear keys and GINA waterstops are important components to control the force and deformation of pipe joints.When the joint is affected by various external and internal factors,the stress on the steel shear keys is caused by the continuous change of the joint angle,in the same time the changes and the deformation of the GINA waterstops in various directions are analyzed separately,and the numerical results of these two components are used as the basis of the research.The corresponding joint change angles under their respective limit states are predicted,and the research is based on the component that first reaches the limit state,and then the research on the corresponding safety alert level of the pipe joints is carried out.By studying the corresponding indicators of joint components,is mainly consists of the following four parts:(1)Use the large-scale numerical simulation software ANSYS to carry out the numerical simulation of a large-scale immersed tube tunnel in Guangdong,and establish the steel shear keys,rubber pads,GINA waterstops,concrete pipe section body structure,end steel shell and other components,then impose constraints and load,obtain the compression-only working performance of the steel shear keys and GINA waterstops under the action of only different hydraulic crimping forces,which provides a reliable simulation basis for the performance of the two components in three different working conditions;(2)Put forward the limit state of the steel shear keys and GINA waterstops in the press-bending conditions,and divide the safety level of the pipe joints in the press-bending conditions:under the condition that a certain hydraulic crimping force is applied to the pipe joints,By applying forced displacement to the numerical model of the pipe joints,the relationship between the joint opening angle and the steel shear key stress and the remaining compression of the GINA waterstop is obtained,and the joint opening angle corresponding to the limit state is compared between the two.To obtain the evaluation index of the safety performance of the joints,and to further ensure the safety performance of the joints,the corresponding evaluation index is classified into different safety levels;(3)Put forward the limit state of steel shear keys and GINA waterstops in compression and torsion conditions,and classify the safety level of pipe joints in compression and bending conditions:under the condition that a certain hydraulic crimping force is applied to the pipe joints,By applying the force to twist the joint to the numerical model of the pipe joints,the relationship between the joint torsion angle,the steel shear key stress and the contact stress of the GINA waterstop is obtained,and the joint torsion angle which get to the limit state of the two components is compared between them.The evaluation index of the safety performance of the joints is obtained,and in order to further ensure the safety performance of the joints,the corresponding evaluation index is classified into different safety level;(4)Put forward the limit state of the steel shear keys and GINA waterstops in the compression and shear conditions,and divide the safety level of the pipe joints in the compression and shear conditions:under the condition that a certain hydraulic crimping force is applied to the pipe joint joints,By applying the shear force to the joint numerical models to cause the joints to undergo shear failure,the relationship between the joint change angle,the steel shear keys stress and the remaining compression of the GINA waterstops is obtained,and the limit is reached by omparing the two the change angle of the joints,corresponding to the state is used to obtain the evaluation index of the safety performance of the joints,and in order to further ensure the safety performance of the joint,the corresponding evaluation index is classified into different safety level;...