Evaluating the Ability of Swell Prediction Models to Predict the Swell Behavior of Excessively High Plastic Soils

Abstract

Lightly loaded structures underneath expansive soils encounter severe damage due to the swell/shrink nature of expansive soils resulting from moisture variations. Billions of dollars are spent every year to repair the damages caused by these soils in the United States and worldwide. Designing structures to accommodate the swelling strains is a major challenge as predicting the swelling potential of these soils accurately is not easy. A wide variety of swell prediction models have been introduced by various researchers to predict the behavior of these often-problematic expansive soils. These models include various properties of soils such as, plasticity characteristics, compaction conditions, consolidation characteristics, moisture content variations, matric suction and clay mineralogical characteristics. However, these models are generally developed with typical moderate to high plastic soils in mind whose plasticity indices range from 25 to 45. Their applicability to soils that have liquid limits in the order of 200% is not well understood. In this paper, the ability of these models to predict the behavior of excessively high plastic soils with plasticity indices ranging from 45 to 85 were evaluated. For this purpose, four existing analytical prediction models that use combinations of abovementioned properties were selected and used to predict the one-dimensional and threedimensional swelling strains on three high swelling soils. These predictions were verified by conducting one-dimensional and three-dimensional swell tests on the three soil types. The swell tests were conducted at three different initial moisture contents to observe how well the models could predict different levels of moisture absorption. The ability of each of the four selected methods in predicting both 1-D and 3-D swell strains was discussed and their relative merits and demerits are highlighted. In addition, finite element modeling was performed to simulate onedimensional and three-dimensional swell tests by using material models that use volumetric and suction changes with moisture contents to simulate expansive soil behavior within the finite element model. The results indicated that while the analytical prediction models gave reasonable results the finite element analysis predicted results were closest to the laboratory measure soils in case both 1-D and 3-D analyses. Among other analytical models the ones that incorporated mineralogical and suction data exhibited better results.

Inverse Analysis Method on the Performance Evaluation of Geosynthetic Reinforcements in Highway Pavement on Expansive Soils

“…However, these methods sometimes miss the mark because of the unpredictability of the issue and the excessive expense of implementation. Traditional chemical stabilization is financially reasonable up to a certain depth, while Ca-based stabilizers can lead to the formation of swelling minerals like ettringite within sight of sulfates (Chittoori et al 2017;Puppala et al 2018). As a solution to fix this segment of the highway, the authors proposed an adaptable mechanical system using geosynthetics that can moderate the uplift pressures from the expansive soils subgrade and protect the pavement surface.…”

Assessing Dispersivity and Expansivity of Clay Soils in the South-East of Yazd with Aim of Investigating Correlation between Them

“…Due to the importance of the subject of swelling soils, many researchers have studied expansivity of soils using direct and indirect methods (e.g. [18][19][20][21][22][23][24]).…”

Evaluating the Effectiveness of Hybrid Geosynthetic Reinforcement System to Mitigate Swelling Distresses on Flexible Pavement Due to Expansive Subgrades

“…Several researchers tried to predict the volumetric movement of expansive soils analytically (Alonso et al 1999;Briaud et al 2003;Vu and Fredlund 2004;Wray et al 2005;Overton et al 2006;Adem and Vanapalli 2013) and numerically (Vu and Fredlund 2006;Rajeev and Kodikara 2011;Puppala et al 2013;Chittoori et al 2017). Analytical methods of swell prediction are based on moisture/suction variation and constitutive laws that link the soil state variables (Briaud et al 2003).…”

“…Several researchers successfully modeled expansive soil and predicted the swelling behavior of the soils (Vu and Fredlund 2006;Abed 2007;Rajeev and Kodikara 2011;Puppala et al 2013;Chittoori et al 2017). …”

“…2013, Chittoori et al 2017. These prediction models that use combinations of above-mentioned properties were selected and used to predict the one-dimensional and three-dimensional swelling strains on three high swelling soils.…”