It is with great pleasure that I, on behalf of the Editorial Advisory Board, welcome you to this, the third edition of this year's Ground Improvement Journal.
As we all know there are an ever-growing number of challenges facing engineers, taking us beyond traditional arenas into new areas including sustainability, covering aspects such as, environmental impact mitigations, net zero targets, and impacts on/from climate change.
As a key part of major construction works the Ground Improvement sector has an important part to play to address these issues. This is occurring all at a time when many countries are facing significant challenges with their existing infrastructure, balancing the needs to reduce environmental impacts whilst achieving cost effectiveness. Add in other factors such as changing population demographics and infrastructure uses, it is vital to ensure that our ground treatments are resilient to whatever the future may hold (Mitchell and Kelly, 2013; Rogers, 2024). A significant challenge indeed and one this journal hopes can facilitate solutions, share best practice and generally provide a forum to discuss future needs and requirements.
The seven papers in this issue highlight aspects associated with ground improvement approaches and essentially sit broadly within two themes, namely: stabilisation approaches, including novel stabilisers, and enhancement to our understand of how our ground improvements approach perform, including enhancing knowledge of how key design parameters are assessed and measured.
Four papers cover a range of topics that discuss stabilisation approaches, an area that offers opportunities to increase our understanding of the complex mechanisms involved using novel more environmentally friendly solutions.
The first paper by Divya and Asha (2024), discusses work using Terrazyme, an enzyme soil modifier that is non-toxic, non-corrosive and produced in a liquid form. Whilst such an approach has been used successfully in recent years (e.g. Saini and Vaishnava, 2015), Divya and Asha's work highlighted the impact on two notable problematic soils, namely: Black Cotton and Lateritic soils, when used as a subgrade material. Through a series of laboratory tests that saw improvements the behaviour of both soils, it was clear Black Cotton soils gained a much more significant improvement. Next Amiri et al. (2024) undertook a laboratory study to examine microstructural properties of marl soils treated with lime (between 0–10%), cured for 28 days, which were then heated to temperatures from 100 to 900°C. Such temperatures although not commonly encountered are seen in several special cases, such as management of radioactive waste storage. The change to a range of geotechnical properties was control by dihydroxylation temperature, where temperature below this witnessed an increase of unconfined compressive strength (UCS) with increase lime content. However, above this UCS decreased with increased lime content.
Following the same general theme, Scheuermann Filho and Consoli (2024) used a porosity/cement index to assess strength and stiffness characteristics of artificially cemented soils. They found from laboratory tests covering 26 mixed designs, conducted on a residual soil that the stiffness and strength correlated well overall with the porosity/cement index. Finally, Spagnoli et al. (2024) using a suite of laboratory data interpretated using a statistical approach developed further understanding of the interdependency of the changing parameters for a sand treated with polyurethane (PU) and an acrylate (AU) grout. They found that generally PU samples achieved better UCS properties then AC, but the impact on other geotechnical parameters were more variable.
The three remaining papers assessed examples of improvements to analytical assessment approaches used in Ground Improvements. The first by Ahmed et al. (2024) considered infiltration issues for embankments, earth structures and tailing dams, examining onset instability issues, assessed using three approaches: drop in stress, second order work, strain ratios. Using these and laboratory data, they tested the impact of tyre crumbs on the instability of sand using a constant shear drained stress path tests. They found that the effective stress at onset instability decreased when up to 20% tyre crumbs were added to sands, whereas above this percentage the opposite was seen. Additionally, they showed that the stress ratio and second order work analysis approach were better at predicting instability.
Following this general theme, Sridhar et al. (2024), assessed laboratory methods to determine horizontal coefficient of consolidation (ch), commonly used in vertical drain analysis. They undertook two commonly used laboratory methods: inward flow from peripheral drainage and outward flow from a central drain. From this they showed that outward flow approaches yielded lower values of ch compared to those from inward flow tests. Additionally, insights into non-uniform distribution of stress and pore water pressure were provided. Finally, Boschi et al. (2024) undertook a comparative study of permeation grouting using Finite Element Methods compared to analytical approaches to evaluate designs and other factors that impact performance of grouted systems. From this they proposed a simplified 1-D analytical approach to predict distance covered in-situ by the grout together with source injection pressures. This provides a useful assessment of temporal evolution of group and maximum injection pressures.
I hope that you find these papers useful, stimulating, and informative and that these papers spark debate on further developments of the role of ground improvements across several areas, not least supporting drives towards Net Zero. On behalf of the editorial panel, may I take this opportunity to thank all our various contributors for their valuable input here.
A useful guide for future authors has been set out by Serridge et al. (2024) in their briefing paper. This provides guidance to potential authors (and reviewers) on the main types of paper submissions that the journal accepts. In addition, it provides guidance on expectations in terms of novelty and content that should be covered, together with future challenges. I can fully recommend it to all authors to consult as an invaluable guide as part of their paper submission process to the journal.
Can I actively encourage our readers to discuss these papers to help further shape our understanding and development of current and future ground improvement processes. Finally, if you have any issues or comments related to the journal more generally, the editorial panel is always pleased to receive any feedback you may wish to provide – thank you.
