The fourth issue of the International Journal of Physical Modelling in Geotechnics presents an interesting mix of studies—from grouting behavior in pipe jacking under varying slurry rheologies, to the mechanical response of model gas pipelines under surface loads, and real-time monitoring of basal strain in a large-scale experimental dam. This issue highlights the vibrant diversity of research and methods that continue to drive innovation within our geotechnical community.
The first paper by Ma et al. (2025) examined the grouting mechanism and its effect during rectangular pipe jacking in soft soil. For this study, a novel jacking grouting device was developed to simulate the entire grouting process through centrifuge model tests, conducted using a beam centrifuge with enhanced gravity under an acceleration of 40 g. Eight sets of centrifuge model tests were conducted to evaluate the effects of varying viscosities and fluid loss of bentonite slurry on the friction coefficient and ground settlement during pipe jacking The test results indicate that reducing the viscosity of the grouting slurry during pipe jacking decreases the friction coefficient between the tunnel and soil. The test results indicate that reducing the viscosity of the grouting slurry during the pipe jacking construction process lowers the friction coefficient between the tunnel and soil, while low fluid loss grouting slurry is more effective in controlling ground surface settlement. The findings are fundamental for enhancing the efficiency and safety of rectangular pipe jacking operations in soft soil, offering valuable insights for both design optimization and practical implementation.
The second paper, by Mertz et al. (2025), investigates the behavior of buried gas pipelines into sand subjected to surface loading. The study involves experimental testing of small-scale pipelines with three distinct wall thicknesses, subjected to both monotonic and cyclic loading conditions. The experimental campaign was carried out in a rigid test tank measuring 1.90 m in length, 0.93 m in width, and 1.00 m in depth. Analysis of the strain distribution and the deformed shape of the pipe reveals a complex response, characterized by a lack of symmetry along the horizontal axis and a distinct heart-shaped deformation pattern. The goal was to generate a comprehensive dataset to enhance the understanding and documentation of soil–pipe–loading interactions, which could subsequently be used to evaluate the relevance and effectiveness of industry design practices.
In the final paper of this issue, Toromanovic et al. (2025) present the results of strains at the base of a large-scale experimental embankment dam, captured using fiber optic sensors across four cross-sections oriented perpendicular to the dam axis. Measurements were continuously recorded throughout the impoundment phase and later during operation, with the upstream water level reaching a maximum of 3.5 meters. Distinct variations in strain were observed across the different zones of the dam. Between the completion of construction and the start of impoundment—with the reservoir still empty—strains begin to develop within the dam body, partly due to settlements. The impoundment drives most of the additional strain development, with strains continuing to evolve over time even after the reservoir reaches its maximum level. This suggests that transient processes are at work, challenging the traditional assumption of an immediate, steady-state formation of saturated zones beneath the seepage line.
The excellence of these contributions attests to the fundamental role played by our dedicated reviewers. In closing, I invite you to explore the studies presented in this issue and to reflect on the valuable insights they offer to our field.
