Prediction of the modulus of elasticity of compacted unsaturated expansive soils

Abstract

A semi-empirical model was proposed by Vanapalli and Oh (2010) for predicting the variation of the modulus of elasticity with respect to matric suction for soils with plasticity index I p values lower than 16%. This model has been extended in this paper to predict the modulus of elasticity of unsaturated expansive soils. The information required for using the model include the soil-water characteristic curve (SWCC) and the modulus of elasticity of soil under saturated condition along with two fitting parameters. Experimental data of triaxial tests for three different expansive soils from the literature were used to examine the validity of the model. The results of the study suggest that the model can reasonably predict the modulus of elasticity of unsaturated expansive soils. The study results are encouraging in reliably using the modulus of elasticity based method proposed by Adem and Vanapalli (2013) for estimation of the volume change behavior of expansive soils.

Hydro-mechanical coupling effect on surficial layer stability of unsaturated expansive soil slopes

“…The fitting parameter a that provides a reasonable estimation of E usnat under low net confining stress was found to fall within the range from 0.05 to 0.15. These results were consistent from the comprehensive modeling studies on heave of expansive soils for several in-situ cases [2,3].…”

Review of methods for predicting in situ volume change movement of expansive soil over time

“…Recently, Adem and Vanapalli (2015a) have extended this model for estimating the modulus for unsaturated expansive soils. The strength of this semi-empirical model lies in its use of conventional soil properties that include the SWCC and the soil modulus of elasticity under saturated condition Esat:…”

“…It was suggested that α =0.05−0.15 and β=2 provide reasonable modeling of the volume change behavior of expansive soils (Adem and Vanapalli, 2015a). Once the matric suction variations within the active zone depth and the corresponding modulus of elasticity are determined, the soil movements can be estimated with respect to time using Eq.…”

Soil Elastic Modulus Determined by Ultrasound Tests

“…The elastic moduli were higher in unpacked test bodies due to partial loss of moisture, causing the suction effect. According to literature, the modulus of elasticity in clay soils is influenced directly by the degree of saturation and suction, being this parameter higher in soils with lower moisture content (Adem & Vanapalli, 2015;Vanapalli & Adem, 2014).…”

“…The factors that may interfere in the ultrasonic pulse on soil and must be considered are both those already determined for other materials and those considered during the determination of the elastic constants of the soil by destructive methods. Vanapalli & Adem, 2014(Adem & Vanapalli, 2015and Oh & Vanapalli, 2016 describe void ratio, compaction energy and soil structure as interfering factors to determine the elastic modulus, therefore, they should also be considered for ultrasonic tests. The porosity, a parameter related to the void ratio, directly interferes in velocity (Chen et al, 2016;Luong et al, 2014) and must be considered in ultrasonic testing, because of the absorption and scattering of the ultrasonic pulse (Bauer, 2000;Cultrone et al, 2001;Lombillo et al, 2014;Qasrawi, 2000;Sarro et al, 2015).…”