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Problematic soils
Published in Alan J. Lutenegger, Soils and Geotechnology in Construction, 2019
The severity of swell in expansive clays is related to amount of expansive clay within the soil, which is approximately related to the clay content and the plasticity. It can be expected that soils with high clay-content and very high plasticity will likely be expansive.
The development of expansive potential in a clay soil of residual origin
Published in C. Di Maio, T. Hueckel, B. Loret, Chemo-Mechanical Coupling in Clays, 2018
Volume changes in unsaturated expansive clay produce ground movements which are capable of causing severe damage to lightly loaded structures. Although expansive soils are recognised as an important geotechnical problem in many parts of the world, research into expansive soils phenomena has only become widespread since the 1960s. Whilst much is known about clay mineralogy and clay particle behaviour, an understanding of expansive clays in a geotechnical context is still evolving. Constitutive frameworks to model expansive soil phenomena, and laboratory tests to characterise expansive soil behaviour are still being developed. There are relatively few published articles which discuss and describe the fundamental behaviour of expansive clay soils and how this behaviour is manifested in a specific geotechnical context.
Measuring stiffness of soils in situ
Published in Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto, Computer Methods and Recent Advances in Geomechanics, 2014
Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto
Expansive clays contain a significant amount of smectite clay minerals such as montmorillonite that swell in the presence of water. The resulting swelling and swelling pressure can cause enormous damage to the infrastructure. On the other hand, this swelling behavior plays a critical role in making swelling clays excellent barrier materials. In this paper, we describe innovative molecular dynamics simulations of Namontmorillonite swelling clay interlayer in a solvation box conducted over a large time of 100 ns to expound the key mechanisms that initiate swelling in these clays.
Engineering properties of fine-grained red mud
Published in International Journal of Mining, Reclamation and Environment, 2023
Hua Tian, David J. Williams, Keith Mandisodza, Chenming Zhang, Sebastian Quintero Olaya, Wenqiang Zhang, Chongyi Tang
Many geotechnical soil properties depend on their constituent mineralogy. Significant quantities of iron minerals were found in both red mud and sand, present as haematite (Fe2O3) and goethite (FeO(OH)), respectively, whereas the main mineral composition of bentonite was smectite, followed by quartz. Smectite often referred to as a ‘swelling’ or ‘expansive’ clay mineral contains interlayer spaces and exhibits a high expansion (swelling) capability in the presence of water [50]. Thus, the absence of smectite and other claylike minerals indicates that red mud is similar to ‘sand’ sample, yet it undergoes essentially infinite swelling as the limited expansion of composition occurs with hydration, which has been proven in related literature [10]. Apart from iron minerals, the red mud featured significant quantities of nosean (Na8Al6Si6O24(SO4)), distinguishing it from the ‘sand’ sample wherein large quantities of gibbsite (Al(OH)3) were present.
Effects of miscellaneous plasticity on behavior of lime-treated kaolinites
Published in International Journal of Geotechnical Engineering, 2021
Mahmood Reza Abdi, Amir Chehregosha, Roohollah Farzalizadeh
Soil improvement can be fulfiled by various techniques all of which are categorized into two main groups as mechanical or chemical stabilizations (Kustov et al. 2004). Mechanical stabilization is primarily accomplished via physical processes by modifying the physical characteristics of soils through vibration or compaction, or by embedding other elements such as drainage columns, piles or geosynthetics (Bahadori et al. 2018; Bahadori and Farzalizadeh 2018; Liu and Vanapalli 2019). Chemical stabilization depends on chemical reactions between the soil particles and the stabilizer (cementitious materials) to attain a desirable impact (Bahadori et al. 2018; Onyelowe and Duc 2018). During the last few decades, various mitigation techniques have been adopted to control the potentially deleterious effects of expansive clays on infrastructures including clay soil replacement, adjustment of water content and compaction, addition of fibrous materials (Abdi and Mirzaeifar 2016; Soltani, Deng, and Taheri 2018), stabilization via chemical substances (Maaitah 2012; Correia, Venda Oliveira, and Lemos 2018) and long-established chemical remediation by means of lime, cement and fly ash addition (Kampala et al. 2013; Jahandari et al. 2019).
Silica fume stabilization of an expansive clay subgrade and the effect of silica fume-stabilised soil cushion on its CBR
Published in Geomechanics and Geoengineering, 2020
B. R. Phanikumar, Jagapathi Raju m, Ramanjaneya Raju e
Silica fume is a fine non-crystalline silica produced in electric arc furnaces as a by-product of alloys containing silica. It is in powder form looking like an ash (Negi et al. 2013). It is a pozzolanic material containing a high amount of amorphous silicon dioxide (Fattah et al. 2015a). As silica fume is hazardous in nature, it is being used in various civil engineering applications such as modification of concretes, alteration of clay behaviour and strengthening of pavement subgrades. Soft clays blended with silica fume and lime showed reduced plasticity and increased workability and strength. Moreover, the clay-silica fume blends were found to be more granular with increased particle size (Fattah et al. 2015b). Kaoline clay mixed with lime and 4% silica fume exhibited improved strength (Alrubaye et al. 2016, 2018). The bearing capacity of a square footing founded in a soft clay improved when the soft clay was grouted with lime-silica fume mix (Fattah et al. 2015a, 2015b). Expansive clay treated with silica fume showed reduced plasticity, free swell index (FSI) and swelling pressure of expansive soils (Negi et al. 2013, Al-Soudany 2017). The degree of stabilization of expansive clays was enhanced when they were treated with cement and silica fume (Goodarzi et al. 2016). Silica fume also effectively reduced desiccation cracks of expansive clays (Kalkan 2009). Further, silica fume was also proved to be effective in controlling progressive swelling and shrinkage of expansive clays subjected to wetting-drying cycles (Kalkan 2011).