Finite Element Simulation Analysis Of Static And Dynamic Response Characteristics On Shield Tunnel Segments

Shield tunnel segments are structures that withstand external loads and provide internal space.In the design of concrete segments,the internal force analysis of the segments is the first step.The FEM model is created by finite element analysis software,and the internal force characteristics of the segment are studied.The equivalent stiffness ring model and the model considering the joint effect are created.The differences and similarities of internal force distribution and numerical value between different models are compared and analyzed.The study shows that the bending moments of the segments between the different models is quite different,while the axial forces and shear forces are roughly similar.The bending moment of equal stiffness ring model is the largest,and that of articulated model is the smallest.The bending stiffness of concrete segment joint has a great influence on the bending moment of segment section.The internal force characteristics on segment are studied by two methods of combining calculation of water and soil pressure and separate calculation of water and soil pressure,and the influence of water depth on internal forces under separate calculation of water and soil pressure is discussed.The results show that the bending moment and axial force distribution between the two methods is similar.In terms of numerical value,the maximum bending moment of combining calculation of water and soil pressure is much larger than that of separate calculation of water and soil pressure,while the difference of the axial force is small.As the water depth increases,the bending moment of the segment changes little while the axial force increases significantly under the method of separate calculation of water and soil pressure.The time-history analysis method is used to analyze the dynamic response of concrete segments under horizontal seismic action.The investigations show that,by comparing with those of the seismic inputs on the bottom of FEM model,the Fourier spectrum of the ground surface has changed greatly compared with the by comparing with those of the seismic inputs on bottom of FEM model due to the filtering and selective amplification of the soil layer.When amplitude-modulated Kobe seismic waves is input from the bottom of FEM model,by comparing with the peak value of accelerations of seismic inputs on bottom of FEM model,the peak value of accelerations on ground surface is only amplified as 1.57 times because theelastic modulus in different soil layer have little different.The maximum bending moment and axial force of the segment induced by seismic loading appear on the arch shoulder and the arch foot,which is much smaller in value than those induced by static soil loading.The position where the maximum bending moment of the segment induced by static soil loading is basically zero induced by seismic loading,and the position where the maximum axial force occurs induced by static soil loading is not large induced by seismic loading.Comparing the maximum bending moment and axial force of the segment induced by static soil loading,the result of static and dynamic superposition is small.The analytic method is used to verify the numerical solution of seismic action,and it is found that the numerical results agree quite well with the analytical ones.