Subsea Tunnel Engineering and Geological Assessment

Subsea tunnel engineering entails the design, excavation and long-term performance of tunnels constructed beneath the seabed for transport corridors, utility conduits and water conveyance schemes. Central to successful delivery is comprehensive geological assessment, which begins with regional seismic and stratigraphic mapping and extends to site-specific investigations of faulting, karstification, sedimentary layering and in situ stress. Ground conditions ranging from soft marine clays and sands to fractured rock masses demand adaptive support systems, such as closed-face tunnel boring machines, shotcrete linings and segmental concrete rings. Geotechnical classification methods guide support design, while real-time monitoring of tunnel face pressures, lining deformation and pore-water pressures informs adaptive construction measures. Key challenges include mitigating water inrush, managing differential settlement beneath sensitive seabed ecosystems and traversing active fault zones. Advances in numerical simulation, integrated geophysical imaging and articulated lining details have substantially improved safety margins, cost certainty and operational life spans. Subsea tunnels now form strategic links in urban rail networks, inter-island roadways and trans-basin water transfer projects, exemplifying the global importance of resilient underwater infrastructure.

Research from Nature Portfolio

One recent study examined the efficacy of an adaptive lining design in reducing the impact of fault dislocation on a long-distance water conveyance tunnel. Numerical models were developed to simulate strike-slip movement across an active fault zone, quantifying displacement, principal stress concentrations and joint hinge deformation. The articulated structure incorporated hinge joints and flexible segments, which reduced induced lining stresses by mitigating relative deformation and tensile peaks. Results demonstrated that adaptive detailing can significantly enhance structural integrity when tunnelling through seismically active regions, providing practical guidance for future fault-crossing subsea works.

Subsea Tunnel Engineering and Geological Assessment publication trend

The graph below shows the total number of articles in subsea tunnel engineering and geological assessment across all publications each year (not limited to Nature Index journals).

Technical terms

Fault dislocation: Relative movement along a geological fault that can deform tunnel structures and induce lining stresses.

Shield tunnelling: A mechanised excavation method using a protective steel or composite shield to advance through soft ground under pressure control.

Cross-hole resistivity: A geophysical technique measuring electrical resistivity between boreholes to map subsurface water-bearing features.

Ground-penetrating radar: A non-invasive method employing electromagnetic waves to image shallow subsurface stratigraphy and detect voids or fluid zones.

References

1. A numerical investigation of the behavior of a tunnel with adaptive anti-dislocation measures subjected to the action of fault dislocation. Scientific Reports (2024).
2. Comprehensive Application of Borehole Fine Detection Methods: A Case Study in Shantou Bay Subsea Tunnel. Geofluids (2024).
3. Numerical Simulation of Construction Disturbances during Bidirectional Advancement of Undersea Large-Diameter Dual-Line Shield Tunneling. Journal of Marine Science and Engineering (2024).
4. Stability of Shield-Bored Tunnel for the Challenge of Nile Crossing. Infrastructures (2021).