Welcome to the April 2025 issue of Geotechnical Engineering (Volume 178, Issue 2). This issue features nine articles highlighting recent advancements in geotechnical engineering, focusing on subgrade stabilisation, excavation performance, soil-structure interactions, drilling efficiency and innovative methodologies. The studies investigate various geomaterials, including sand, clay, and rock, utilising and employ laboratory testing, field experiments, numerical simulations, and theoretical modelling. These contributions provide valuable insights into practical geotechnical challenges and offer innovative solutions that enhance infrastructure resilience and sustainability.
With the rapid expansion of high-speed rail (HSR) networks and large-scale transportation projects, subgrade stability remains a critical challenge. Bai et al. (2025) evaluate high-pressure jet-grouting (HPJG) for mitigating lateral deformation in HSR subgrades, emphasising the critical role of excess pore water pressure dissipation in improving the long-term performance of railway infrastructure. Similarly, Di et al. (2025) examine the behaviour of diaphragm walls, servo steel strut systems, and isolation piles in deep strip foundation pits adjacent to HSR lines. Their study underscores the necessity of integrating multiple geotechnical reinforcement methods to control deformation in complex excavation projects. Xu et al. (2025) introduce an assembled H-shaped steel strut (AHSS) system with a servo mechanism for deep subway station excavations in soft soil. Their study, based on field-monitored axial forces, retaining wall displacements, ground settlement, and tunnel movement, demonstrates the system’s ability to maintain stable axial forces and control excavation deformation. These studies reinforce the need for innovative geotechnical strategies to support the ongoing global expansion of transportation infrastructure.
Advancements in site characterisation and drilling optimisation continue to shape geotechnical engineering practices. Shen et al. (2025) explore the sensitivity of drilling efficiency to operational parameters using full-scale hydraulic drifter tests, identifying key factors that influence penetration rates and energy consumption. Their research offers practical insights for improving drilling performance in challenging ground conditions. Wong et al. (2025) examine energy transfer efficiency and stress wave propagation during standard penetration tests (SPTs), analysing over 4,000 energy measurements and using particle image velocimetry (PIV) to visualise wave behaviour. Their study reveals discrepancies between theoretical and measured wave speeds, and quantifies major sources of energy loss. Additionally, Dienstmann et al. (2025) integrate probabilistic modelling into piezocone drainage effect analysis, enhancing the reliability of site investigation methods, particularly in complex and heterogeneous soil conditions. Collectively, these advancements improve the accuracy of geotechnical testing and support more informed engineering decisions.
Innovations in geotechnical materials and technologies are paving the way for more resilient and sustainable engineering solutions. Shirdel and Farzam (2025) evaluate the mechanical performance of 3D-printed geogrids, examining how aperture shape, junction configuration, and rib thickness influence soil reinforcement efficiency. Their research highlights the potential of additive manufacturing in geosynthetic applications, paving the way for novel soil stabilisation techniques. They also demonstrate how customised lattice structures can be designed for specific soil reinforcement needs. Norris and Yang (2025) introduce a non-linear stress-strain relationship for soil and rock, refining constitutive modelling approaches used in geotechnical simulations. Their work provides a framework for more accurate soil behaviour predictions, particularly in high-stress environments such as deep excavations and tunnel stability assessments. Chen et al. (2025) employed the discrete-element method (DEM) to investigate seepage erosion in sand subgrades caused by buried pipeline leakage, providing critical insights into geotechnical failure mechanisms. Their findings suggest that changes in particle transport mechanisms under varying hydraulic gradients significantly influence subgrade stability, which is crucial for pipeline infrastructure management. These studies provide valuable contributions to the optimization of geotechnical materials and advanced simulation techniques, offering new solutions for soil reinforcement and deformation analysis.
In conclusion, this issue presents significant advancements in geotechnical engineering, highlighting research that contributes to the development of resilient and sustainable infrastructure. We hope these studies provide valuable insights for researchers and practitioners, inspiring continued innovation in the field.
