Dynamic Stress Analysis of a Circular‐Lined Tunnel in Composite Strata‐SH Wave Incidence

Abstract

It is necessary to study the problem of seismic wave scattering in composite stratum for tunnel engineering because the existence of composite strata will make the stress of tunnels more complicated during earthquakes. In this thesis, a series solution of the scattering wave field of the composite strata and lining is obtained using the complex function method. According to the stress and displacement boundary conditions between the composite stratum and the lining, a series of equations are established and are solved by means of Fourier transformation and finite term truncation, and the calculation errors are also discussed. Through programming calculations, the dynamic stress concentration factor (DSCF) of circular tunnels in the two types of composite strata, “hard-over-soft” and “soft-over-hard,” is analyzed when SH waves propagate, and certain conclusions on the scattering of SH waves that are distinguished from the case of single homogeneous layers are reached. The research in this article reveals some phenomena. For the Q345 steel lining in the calculation examples, it is found in this paper that increasing the thickness of the lining is effective to reduce the influence of the DSCF. But, for C30 concrete, increasing the thickness of the lining reduces the DSCF of the outer surface while increasing the DSCF of the inner surface.

Anti-Plane Dynamics Analysis of a Circular Lined Tunnel in the Ground under Covering Layer

“…In our previous research work, the two soil layers with large differences in rock and soil mechanics and engineering geology were simplified into the covering soil layer and the lower soil layer. The dynamic response of a circular lined tunnel [23] and a partially debonded circular lined tunnel [24] in the covering soil layer under the action of SH waves are studied. Accurate results are obtained, which can provide theoretical reference for the seismic design of tunnels.…”