In the depths of the ocean, where submarine tunnels carve through rock masses, a new numerical model is set to revolutionize our understanding of these critical infrastructure projects. Led by Lan Cui of the State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, a groundbreaking study has been published in the Journal of Rock Mechanics and Geotechnical Engineering, which delves into the coupled effects of strain-softening and seepage on the stability of submarine tunnels.
Submarine tunnels are pivotal for the energy sector, facilitating the transport of resources and connecting offshore installations to mainland grids. However, the stability of these tunnels is continually challenged by the seepage of groundwater and the strain-softening of the surrounding rock. These factors can expand the plastic region of the rock, potentially compromising the tunnel’s integrity. Cui’s research addresses this challenge head-on by developing an enhanced numerical model that considers these coupled effects.
The traditional approach to modeling these interactions has fallen short, as it relies on uniform equations that do not accurately represent real-world rock mass behavior. Cui’s updated numerical procedure, however, is derived from experimental results and incorporates hydro-mechanical parameters such as elastic modulus, Poisson’s ratio, Biot’s coefficient, and permeability coefficient. These parameters are characterized by fitting equations derived from experimental data, providing a more accurate representation of the rock’s behavior.
“The evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice,” Cui explains. “Our updated numerical procedure addresses this limitation by incorporating experimental data, offering a more precise model for predicting the behavior of rock masses surrounding submarine tunnels.”
The implications of this research are vast, particularly for the energy sector. By understanding the stress and strain fields in the rocks surrounding submarine tunnels, engineers can design more stable and durable structures. The model’s ability to simulate the effects of initial pore water pressure, Biot’s coefficient, and permeability coefficient on stress, displacement, and water-inflow provides valuable insights for optimizing tunnel design and construction.
One of the key findings is that the initial permeability coefficient exerts the most significant influence on the stress field. This discovery could lead to more targeted dewatering strategies, enhancing the stability of submarine tunnels. “Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters, it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure,” Cui advises.
As the energy sector continues to expand its offshore operations, the demand for reliable submarine tunnels will only increase. Cui’s research, published in the Journal of Rock Mechanics and Geotechnical Engineering, offers a significant step forward in ensuring the stability and longevity of these critical infrastructure projects. By providing a more accurate and comprehensive model, this study paves the way for future developments in submarine tunnel design and construction, ultimately benefiting the energy sector and beyond.
