Dynamic stress response of saturated soil subjected to vertical and horizontal moving loads inside a circular tunnel

Abstract

This study proposed an improved tunnel model for the evaluation of dynamic stress of the saturated soil subjected to vertical and horizontal moving loads. Based on this model, the response of dynamic stress of the saturated soil subjected to three typical loading scenarios is systematically analysed: (1) vertical moving loads, (2) combined vertical moving load and longitudinal horizontal load due to the braking of a train, and (3) combined vertical moving load and tangential horizontal load during the turning of a train at small curved sections. The simulated results reveal that soil permeability, load speed and load frequency have a significant influence on the dynamic stress of the saturated soil. The two types of horizontal loads have considerable effects on the shear stress but have negligible influence on the normal stress and pore-water pressure of the saturated soil.

The Damage Deterioration Mechanism of Tunnel Structure under the Effect of Thermo-Mechanical Coupling and Its Maintenance

“…During the construction and operation of the deep-buried long big tunnels, the thermal and mechanical physical fields are combined significantly [16][17][18][19][20][21][22]. Under the impact of large temperature difference of "hot inside and cold outside", high-gradient temperature field would appear in the tunnel, which can cause serious deformation to lining concrete of the tunnel support structure, and it might damage the tunnel structure in severer cases [23][24][25][26]. At the same time, the surrounding rock of the tunnel support structure is subjected to high stress, which can lead to phenomena as such as cracking, hydraulic cracking, and instability, bringing threats to the safe operation of the tunnel.…”