Sliding base isolation can achieve independence between the seismic isolation period and the liquid sloshing period. Additionally, it has dissipation advantages for liquid-storage structures. However, when earthquake actions are large, the isolation layer displacement exceeds the limit value, which can lead to auxiliary pipeline damage and liquid leakage. Therefore, a corresponding displacement-limiting study is necessary. Considering the liquid-solid interaction, a simplified model of a rectangular liquid-storage structure (RLSS) with arc displacement-limiting devices is established, and its validity is verified using numerical calculations. Based on the structural safety and deformation capacity of the displacement-limiting device, the limit of the isolation layer displacement is defined. The factors affecting the hysteretic energy dissipation of the displacement-limiting device and the dynamic responses of the RLSSs are studied. The results indicate that the section size and radius of the arc limiting device considerably influence its hysteretic energy dissipation, but the effects of the cross section shape are extremely small. When the friction coefficient is reasonably designed, the wall tensile stress and liquid sloshing height of the sliding base-isolated RLSS with limiting devices can be effectively reduced. This new damping method is of great significance for the prevention and control of the two common types of failure modes for concrete RLSSs, namely, wall cracking and liquid overflow.

The rock mass surrounding a subsea tunnel often contains seawater, and the coupled effects of an earthquake and seepage introduce more uncertainty into analyses of tunnel safety. However, research on this topic is still lacking. In the present study, models of structure and fluid fields were established by considering the effect of a two-dimensional viscoelastic boundary condition, and the stability of a cross-sea tunnel structure under seepage and a bidirectional earthquake was studied. Using a static strength-reduction method on the basis of dynamic finite elements, a stability-safety coefficient was obtained. In addition, the influences of sea depth, overlying rock thickness, and permeability coefficient on the seismic dynamic stability-safety coefficient and varying characteristics of the plastic zone in a cross-sea tunnel structure under seepage and a bidirectional earthquake were studied through numerical examples. The results showed that under this type of earthquake, plastic zones first appeared on both sides of the tunnel arch feet and in the peripheral areas of the arch shoulders; by contrast, the vault was secure, and no plastic zone appeared in this area. When all factors were considered, the plastic zones extended farther when the overlying rock thickness and sea depth were greater. When the overlying rock was thick and the rock mass surrounding the tunnel was only slightly weathered, the rock mass was close to intact, and as a consequence, the permeability coefficient did not significantly affect the development of the plastic zone or the stability-safety factor. The influences of these three parameters on the safety of a subsea tunnel, as obtained in this paper, can provide a theoretical basis for the reasonable design of submarine tunnels.

When a river-crossing shield tunnel is excavated in water-rich soft clay strata, the mechanical properties of the segment lining structure are significantly affected by the water pressure and fluid-solid coupling, especially when the water level changes under the effect of tides. In this study, based on the modified conventional method, the mechanics and deformation characteristics of a lining structure under different high water pressures and fluid-soil coupling effects were analyzed by a finite difference method. The results show that when the water level increases, the axial force of each part of the lining structure increases and the bending moment decreases gradually. The lining structure of underwater tunnel presents a transverse duck-egg deformation with vertical shrinkage and transverse expansion under fluid-solid coupling action. Due to large bending moment, small axial force, and large displacement at the vault and arch bottom of the lining structure, the segment concrete in these parts cracks easily and the joints are prone to warping. Considering fluid-solid coupling effect when an underwater shield tunnel passes through high water pressure strata, the axial force of the segment lining structure is large and the bending moment is small, which makes the stress of the lining structure more reasonable.