It is generally accepted that anthropogenic activities have brought significant changes in the climate system, most notably the unequivocal warming of the earth. The reality has forces researchers and geotechnical engineers to enhance their fundamental understanding of soil-atmosphere processes. Anticipated changes in climate conditions such as extreme temperatures and rainfall will likely lead to changes in soil behaviour which will influence geotechnical works such as embankments. Soil strength is fundamentally governed by moisture content where wetter soils are generally weaker. Temperature has also been shown to significantly influence the shear strength and volumetric behaviour of soil, however, its impact is seldom studied or included in designs. As such, altered temperature and rainfall loads will impact geotechnical works and lead to long-term seasonal deformations that may cause severe safety and maintenance problems. Theses long-term impacts considering temperature are neither well studied nor well-understood and should be investigated.
To manipulate the artificial atmosphere in a model container and simulate various climate conditions during centrifuge testing, a novel environmental chamber was created (Archer & Ng 2018). This chamber is capable of separately controlling air temperature (18-50 °C), relative humidity (RH) (30-100%), radiation (300-1400 W/m2), wind (0.2-7 m/s) and rainfall (5-100 mm/h), inflight. The environmental chamber is mounted on top of a model container with inside dimensions of 1200 mm × 900 mm × 800 mm (length x width x height). The chamber has been tested successfully at centrifugal acceleration of up to 100 g.
The environmental chamber provides a powerful tool to model the soil-atmosphere interaction and its impact on infrastructures. The novel design warrants long-term performance which enable researchers to study the effect of cyclic environmental boundary on soil, improving the state of art on the effect of a changing climate on earthworks.
Overall view of a strongbox mounted with the environmental chamber
Elevation view of the model space inside the environmental chamber
- Archer, A. & Ng, C. W. W. (2018). Effects of temperature and relative humidity on a clay embankment: centrifuge modelling. Géotechnique Letters 8, No. 2, 138-143, https://doi.org/10.1680/jgele.18.00002.
Archer, A. & Ng, C. W. W. Centrifuge Environmental Chamber. US patent application - 15/425,501; Filed on 6 February 2017. US Provisional Patent Application - 62/388,691; Filed on 4 Feb 2016. Pending.