Welcome to the December issue of Geotechnical Engineering. Yes, I am surprised as you are that we have once again zipped through another year already, but we have six lovely papers to cheer you up for the festive season. We present six interesting papers on subjects ranging from laboratory tests on cemented soils from Brazil, stability and settlement analyses on embankments on soft soils, the behaviour of embankment dam filters, design of soil nailed structures and simulation of siphon drains.
We start off with two papers from Brazil, the first by Carretta et al. (2022) and the second by Dienstmann et al. (2022). Carretta et al. (2022) use a suite of geotechnical laboratory tests, including: unconfined compressive strength, oedometer, bender elements, monotonic and cyclic triaxial tests, on both undisturbed and remoulded specimens to characterise a uniquely naturally cemented residual soil from Brazil (Figures 1 and 2). This study on the behaviour of a naturally cemented Brazilian soil links nicely with Fante et al. (2022), which is published online ahead of print.
Photographs of soil sample collected in the field and once transported to the laboratory (Carretta et al., 2022)
Photographs of soil sample collected in the field and once transported to the laboratory (Carretta et al., 2022)
Photographs of the tested specimens before and after testing (Carretta et al., 2022)
The second paper by Dienstmann et al. (2022) looks at the major infrastructure project of the BR 470 federal highway in Brazil, which crosses deep soft soil deposits and discusses the use of pre-loading and the use of prefabricated vertical drains (PVDs) to reduce settlements (Figure 3). It is important to note that the use of field instrumentation to measure the evolution of settlements are key to evaluating the performance of pre-loading and PVDs. If you are interested in PVDs, you might also be interested in Fakharian and Mehdizadeh (2015) and two ahead of print papers: Hayashi and Hashimoto (2022) and Nguyen et al. (2022) from this publication.
Continuing on the theme of embankments, we have Shourijeh et al. (2022) discussing the effects of moisture content on filtration of mixed core soils in embankment dams, followed by López Ramírez et al. (2022) on the safety margin from characteristic values in settlement calculations of embankments on clay.
Focussing on the issue of dam failures caused by internal erosion, Shourijeh et al. (2022) performed a suite of no-erosion filter (NEF) tests (Figure 4) on a range of filter gradings at different water contents. Building upon their previous work on NEF testing (Soroush et al., 2008), their experiments show that the filter performance is dependent on the moisture in excess of optimum, the particle size with 15% finer in filter gradation and the fines content of the filter. Those interested in the stability of earth dam filters may be interested in Vakili and Selamat (2014) and Zhou et al. (2017).
With the upcoming revision of Eurocode 7 in mind, López Ramírez et al. (2022) examine the safety margin that results from the estimation of characteristic soil values when calculating settlements of embankments on soil clays using Monte Carlo simulations. They conclude that the safety margin is inconsistent between various cases, ascribed to the variability imposed by different levels on non-linearity in compressibility and degree of consolidation considered. For those interested, we have previously published a number of papers on a similar vein, including Baxter et al. (2008), Lo and Li (2007), Prästings et al. (2019) and Watkins et al. (2011).
Moving on to our fifth paper, Ehrlich et al. (2022) look at the effect of construction and design factors on the behaviour of nailed-soil structures (Figure 5), where we have a wealth of articles already published on this topic, including Bridges and Gudgin (2014), Bridle and Davies (1997), Ortigao et al. (1995) and Yang (2007).
The final paper in this issue is from Zhejiang University by Lv et al. (2022), who have analysed siphon drainage (Figure 6) using iterative seepage analyses in Python, validated with the case study of the Shaqiucun landslide, China.
Finally, I would like to take this opportunity to apologise for our long print queue. Rest assured that the Editorial team is working hard behind the scenes to remedy this as best as we can and in the meantime, we want to remind our readership that Geotechnical Engineering publishes its accepted papers online ahead of print. Please see our current pipeline of accepted papers here: https://www.icevirtuallibrary.com/toc/jgeen/0/0.
