Stability on the Excavation Surface of Submarine Shield Tunnel Considering the Fluid–Solid Coupling Effect and the Equivalent Layer

Abstract

The support pressure on an excavation surface is a critical factor in the ground deformation and excavation stability of a submarine shield tunnel. The shield tail gap and the disturbance zone of grouting behind the tunnel wall are also important influencing factors. However, the effects of these factors on excavation stability are difficult to quantify. Consequently, a homogeneous, elastic, and annular equivalent layer is employed to simulate the thin layer behind the tunnel wall. Using COMSOL Multiphysics software, the effects of the water level depth, the thickness of the equivalent layer, the diameter of the shield tunnel, and the internal friction of soil and tunnel burial depth on the excavation deformation and ground surface subsidence of a submarine tunnel are considered with regard to the fluid–solid coupling effect. The result show that the surface subsidence of the case with respect to the fluid–solid coupling effect and the equivalent layer is larger than that without interstitial fluid and the equivalent layer, indicating that the present model can better simulate the stability of tunnel excavation. Therefore, it is important to consider the impact of the fluid–solid coupling effect and the equivalent layer on the deformation of the excavation face and ground surface subsidence.

Numerical Simulation of Construction Disturbances during Bidirectional Advancement of Undersea Large-Diameter Dual-Line Shield Tunneling

“…Concerning uneven strength distributions in dangerous working conditions, Li et al [19] used finite element software to analyze in detail the interaction between the rock seepage effect and the secondary stress field of tunnels to obtain the distribution of the tunnel plastic zone of the Qingdao undersea tunnel's surrounding rock fragmentation. Wang et al [20] studied the influence of the shield diameter, equivalent layer thickness, excavation surface support pressure, and other factors on the settlement of undersea tunnels from the perspective of fluid-solid coupling and verified the accuracy of the model. Dias, et al [21] monitored two cross tunnel sections of underground work for a subway in Lyon, France.…”

Optimizing the Support System of a Shallow Buried Tunnel under Unsymmetrical Pressure

“…Miao et al [30] studied the mechanism of significant deformation in shallowly buried and terrain-biased tunnels after initial support using a combination of on site monitoring, laboratory rock expansion tests, and three-dimensional numerical simulation. Due to the limitations of on site monitoring and experimental methods, an in-depth understanding of the characteristics and deformation patterns of the tunnel under unsymmetrical pressure often relies on numerical simulation techniques [31][32][33][34][35][36][37][38]. Many scholars have carried out relevant research through numerical simulation.…”