Dynamic Response of Lining Tunnel in Unsaturated Orthotropic Soil under Endogenous Blast Loading

Abstract

In this study, a computational model is developed to investigate tunneling in unsaturated orthotropic anisotropic media subjected to endogenous blast loading. The tunnel lining is modeled as a uniform elastic medium and the soil around the lining is regarded as an unsaturated orthotropic medium, taking into account the contact between the soil and the lining. Using Biot’s theory, the governing equations for the tunnel and the unsaturated orthotropic soil in the Cartesian coordinate system are derived via Laplace and Fourier transform methods. The integral dynamic response solution is then obtained by applying inverse transforms. Furthermore, this study examines the effects of saturation and soil properties on the transient dynamic response characteristics of the tunnel lining and surrounding soil under endogenous blast loading, in comparison to isotropic media. The results demonstrate that the proposed solution effectively describes the dynamic response of the lining and unsaturated orthotropic soil under blast loading conditions. The results show that under the effect of endogenous blast loading, the lining and the surrounding soil show a tendency to attenuate oscillations with time and eventually reach the dynamic equilibrium state. Through the comparative study of the isotropic soil, the findings indicate that different characteristics of soil have a significant impact on its dynamic response. However, the change of the saturation of the medium parameters has little effect on the dynamic response of the tunnel lining and unsaturated orthotropic soil under blast loading.