Photo above: Soil stabilisation (Photo: Keller)
GOAL remedies current gaps in soil stabilisation by:
- validating non‐destructive sensing technologies to quantify the field behaviour of stabilised soil
- developing an automated design framework that merges knowledge and monitoring data
- creating green value chains around industry‐by-products as sustainable, climate‐friendly and cost-effective materials for soil stabilisation.
Soil stabilisation is chemical or physical treatment of soil to improve its strength or other engineering properties. The market for soil stabilisation has been steadily increasing over the past decades, but current practice of soil stabilisation is mainly using materials (e.g., lime and cement) with significant carbon emissions. It also lacks digitalisation, automation and effective collaboration.
Digitalisation and automation of the soil stabilisation industry
A key aspect of soil stabilisation is to evaluate strength and deformation properties of the improved ground in the field. Today's methods are based on destructive methods where the stabilised soil is either tested in the field using a penetrating device or sampled and transferred to the laboratory (Ref. 1, 2).
Recently developed sensor technologies and methodologies enable non‐destructive and distributed sensing, and open new possibilities to better understand the behaviour of infrastructure (Ref. 3). The building and construction industry currently lacks monitoring methods for a detailed assessment of the behaviour of stabilised soil. There is an urgent need to transform soil stabilisation using latest sensing and monitoring techniques, more sustainable materials and automatized data‐driven design solutions.
Sustainable binders to stabilise soil
Several laboratory studies have shown the potential of so‐called sustainable binders to stabilise soil including blast furnace slag, fly ash and biochar (Ref. 4-9). These works provided important insight into the mechanical performance (e.g., strength and deformation properties) of different binders and showed that a single binder that outperforms others in a range of soils is likely not existing.
The properties of soils stabilised with alternative materials at full‐scale remains understudied. As a result, in‐situ soil stabilisation utilising alternative materials is scarce in practice. The impact of using alternative binders such as industry by‐products on the field execution (i.e., mixing process) and the effect of this interaction process on the properties of the stabilised soil must be further explored to put alternative binders into the soil stabilisation practice.
Knowledge needs and challenges
GOAL addresses several knowledge needs related to increased automation, digitalisation and sustainability of the soil stabilisation industry. This has resulted in the following Work Packages (WPs):
- WP1 – Knowledge generation: lab testing
the geomechanical and geophysical behaviour of Norwegian soils (e.g., soft clay, quick clay and peat) stabilised with industry by‐products such as ashes, steel slag and biochar
- WP2 – Sustainability: environmental and economic impacts
the way in which the environmental impact of alternative materials for soil stabilisation is evaluated including a consideration of the entire life cycle and the fate of contaminants
- WP3 – Upscaling: field application
the field performance of soils stabilised with industry by‐products
- WP4 – Digitalisation and automation: smart soil stabilisation
the feasibility and reliability of distributed fibre optic sensing (DFOS) and geophysical methods to measure the engineering properties and uniformity of stabilised soil and data driven design of soil stabilisation enabling automation of soil stabilisation in the field
- WP5 – Catalysing innovation: enabling sustainable soil stabilisation
the crucial preconditions and stakeholders that enable to utilise industry by‐products in construction projects and knowledge exchange
- Karlsrud, K., Eggen, A., Nerland, Ø. and Haugen, T., 2015. Some Norwegian experiences related to use of dry-mixing methods to improve stability of excavations and natural slopes in soft clay. In Proceedings of the Deep Mixing 2015 Conference Deep Mixing 2015, San Francisco, CA, USA (pp. 87-100).
- Paniagua, P., Bache, B.K., Karlsrud, K. and Lund, A.K., 2020. Strength and stiffness of laboratory-mixed specimens of stabilised Norwegian clays. Proceedings of the institution of civil engineers-ground improvement, pp.1-14.
- Soga, K. and Schooling, J., 2016. Infrastructure sensing. Interface Focus, 6(4), pp.20160023-20160023.
- Åhnberg, H., 2006. Strength of Stabilised Soil-A Laboratory Study on Clays and Organic Soils Stabilised with different Types of Binder, PhD dissertation. Lund University.
- Lau, J., Biscontin, G. and Berti, D., 2020. Effects of biochar on cement-stabilised peat soil. Proceedings of the Institution of Civil Engineers-Ground Improvement, pp.1-12.
- Yong-Feng, D., Tong-Wei, Z., Yu, Z., Qian-Wen, L. and Qiong, W., 2017. Mechanical behaviour and microstructure of steel slag-based composite and its application for soft clay stabilisation. European Journal of Environmental and Civil Engineering, pp.1-16.
- Jegandan, S., Liska, M., Osman, A.A. and Al-Tabbaa, A., 2010. Sustainable binders for soil stabilisation. Proceedings of the Institution of Civil Engineers-Ground Improvement, 163(1), pp.53-61.
- Fasihnikoutalab, M.H., Pourakbar, S., Ball, R.J., Unluer, C. and Cristelo, N., 2020. Sustainable soil stabilisation with ground granulated blast-furnace slag activated by olivine and sodium hydroxide. Acta Geotechnica, 15(7), pp.1981-1991.
- Pardo, G.S., Sarmah, A.K. and Orense, R.P., 2019. Mechanism of improvement of biochar on shear strength and liquefaction resistance of sand. Géotechnique, 69(6), pp.471-480.