Welcome to the August edition of Geotechnical Engineering (GE). Before introducing the papers in this edition, I would like to bring you up to date with some journal news. As we approach the autumn, some members of GE's editorial panel are nearing the end of their 3-year term and the journal therefore requires high-calibre professionals from academia and industry to replace those leaving the team. We are particularly interested in attracting applications from geotechnical engineers with consulting or contracting experience, based in the UK and Northern Europe. If you, or someone you know, has the right qualities to become a panel member then please send a short CV of no more than four pages to Dr Alison McAnena at alison.mcanena@icepublishing.com. The deadline for nominations is 30 September 2014.
It is always an enjoyable experience reading papers in GE as they cover such a wide variety of topics and originate from both academics and practitioners from all corners of the globe. This edition boasts a collection with a truly international origin proving, once again, that GE caters for needs of a wide range of ground-engineering professionals. We are privileged to have such high-quality submissions in this edition and it gives me great pleasure to introduce them to you.
The first paper (Mahabad et al., 2014) provides a comparison of three-dimensional finite-element (FE) modelling of a concrete face rockfill dam (CFRD) verified by empirical relationships and observed behaviour of 15 similar dams. The authors have chosen the Glevard dam in Iran to present two distinct models of the face during first impounding. The dam is impressive, being 110 m high and with a crest length of 276 m, and the two models show similar, but distinct, stress and movement distributions. The paper determines that CFRD modelling using FE provides a useful analysis, however, it was noted that the simplified model without vertical face joints underestimated the in-plane horizontal deformations and some axial forces in the face, which is important when considering the design and construction of the face slab. This paper was written during the construction of the Glevard dam and it will be fascinating to read a second instalment of this story detailing the actual response of the CFRD during its first filling; I do hope the authors have this in preparation.
The next paper (Crapper et al., 2014) describes an assessment of the earthworks on the Bo'ness and Kinneil Heritage Railway (HR) dating from 1851, part of which runs for 2·4 km on an earthwork up to 15 m high and below a cut in soil and rock. HRs are subject to the same safety requirements as any other UK rail operation and have generally operated with an improving safety record. Over recent years, however, there has been a series of safety incidents, many of which can be attributed to ageing earthworks, either as a result of poor management or adverse weather conditions. A management-led, risk-based assessment procedure has been developed to enable staff to assess the earthworks properly. The authors conclude that, with some refinement, the process may be of use on other HRs. It is hoped this will help to keep one of my personal favourite holiday activities going for years to come.
The third paper, by Zhao et al. (2014), describes how centrifuge model tests on slopes with combined active (pre-stressed) and passive anchors are designed to investigate load sharing between the two anchor systems. The analysis shows that passive anchors make a contribution to the stability of the slope by attracting a portion of the stresses produced by deformations in the model, both at a local level and to overall stability. The authors describe how the increasing use of combined systems is not only enabling higher and steeper slopes to be stabilised to required minimum safety standards, but also how this is achieved at lower cost than using active systems alone.
Sivakumar et al. (2014) tackle the issue of settlement of footings in granular soils, some with granular foundation columns, in fluctuating groundwater levels; a problem that is particularly pertinent to coastal areas where collapse settlement may occur in fine granular soils. It would be interesting to follow up this research with further testing over a longer time period. Assessment of the quantity of fines migration would be of benefit in assessing the settlement attributable to migration and the additional load imparted to the columns.
The fifth paper (Qian et al., 2014) describes the response of bell piers for lattice electricity pylon foundations in the Gobi Desert. Spread foundations were traditionally used with native soil backfill to provide mass for uplift resistance, however, bell piers minimise waste production and environmental damage and therefore provide an economic alternative with the wider ‘bell' at the toe of the pier providing good tension capacity. They conclude that bell piers follow a typical two-phase load–displacement response comprising an initial linear response followed by a non-linear phase as load increases. This approach could have implications for the current renewable electricity infrastructure improvements and additions in the UK.
The penultimate paper, by McNamara et al. (2014), and one of my favourites in this edition, describes the novel use of hollow section cast-in-situ bored piles. The authors cite a number of advantages of using this particular pile type, primarily the considerable saving on materials and the potential for re-use. These piles are suitable for internal inspection at a later date and allow extension by boring through the base as well as being ideal for use as energy piles. Provided some of the construction and reinforcement issues can be overcome, then the economics of this pile type have considerable benefits. I would not be surprised to see this pile type high on the list of options at the start of a project, not least for its contribution to sustainability and energy targets.
The final paper in this edition, by Huang et al. (2014), describes a numerical model calibrated by a full-scale field test for lateral loading of piles within a reinforced earth wall. Several conclusions are made regarding the spacing and interaction of the pile group and the relationship to the state and type of backfill. This extremely interesting paper, bringing both the numerical and practical together, serves as a fitting conclusion to this edition.
If you would like to raise any particular points regarding the papers published please consider contributing to the journal in the form of a discussion piece or a briefing note. Instructions on the preparation and submission of discussion and briefing notes are included at the end of each paper.
For up-to-date information on GE please visit http://www.icevirtuallibrary.com/content/serial/geng.
