scholarly journals Behaviors of rainfall infiltration and drainage characteristics of unsaturated soils under relatively high suction state

2021 ◽  
Vol 16 (1) ◽  
pp. 35-47
Author(s):  
Takafumi KITAOKA ◽  
Hiroyasu OHTSU ◽  
Satoshi NONAMI ◽  
Thirapong PIPATPONGSA ◽  
Atsushi MATSUMOTO
Keyword(s):  
Unsaturated Soils ◽  
Rainfall Infiltration ◽  
High Suction

scholarly journals Suction effects on the tensile strength and unconfined compression of unsaturated soils

2021 ◽  
Vol 337 ◽  
pp. 01016
Author(s):  
Pedro Roque ◽  
Mariana Motta ◽  
Tácio de Campos
Keyword(s):  
Tensile Strength ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Great Influence ◽  
Dew Point ◽  
Unconfined Compression ◽  
Residual Soils ◽  
Colluvial Soil ◽  
First Moment ◽  
High Suction

The soil-water characteristic curve is an important relation of unsaturated soils, that expresses the variation of the amount of water retained in the soil as a function of its suction. In these soils, drying or wetting can have a great influence on their resistance parameters. This work presents and discusses the effects of increased suction on the tensile strength and unconfined compression of unsaturated soils. Suction was evaluated using the filter paper and the dew point technique, while the resistance parameters were obtained through the “Brazilian Test” and uniaxial compression. Three different soils from Rio de Janeiro were studied: two young residual soils, in which the influence of the soil structure was also verified through tests on undisturbed and reconstituted samples, and a colluvial soil. The results allowed to conclude that the increase of suction, in a first moment, generates an increase in the resistance parameters of these soils. With the continuation of the drying process, the mechanical behaviour of the soils varied, being able to maintain the resistance or showing a drop related to high suction values.

scholarly journals Modelling Unsaturated Soil Response Beyond Residual Suction State via Vapor-Pressure Controlled Triaxial Testing

2020 ◽  
Vol 195 ◽  
pp. 03029
Author(s):  
Mathilde Morvan ◽  
Ujwalkumar D. Patil ◽  
Laureano R. Hoyos ◽  
Surya S. C. Congress ◽  
Anand J. Puppala
Keyword(s):  
Unsaturated Soils ◽  
Silty Sand ◽  
Flow Rule ◽  
Model Parameters ◽  
Peak Strain ◽  
Reasonable Accuracy ◽  
Soil Response ◽  
Proposed Model ◽  
High Suction ◽  
Volumetric Response

Most of the previous research has been focused on developing and validating constitutive models to predict response of unsaturated soils in low-medium suction range. However, there is a scarcity of efforts in developing soil models to simulate its mechanical response in high suction range, particularly above the residual suction. This article presents a new constitutive model introducing net stress and suction as two independent variables. Furthermore, non-associative flow rule incorporating modified stress-dilatancy relationship to take unsaturated state into account is introduced to improve the model results in low-medium to high suction range. The essential soil model parameters are calibrated using suction-controlled triaxial test results for predictions of compacted silty sand response at high values of total suction above residual suction. Preliminary simulations show that proposed model can reasonably simulate the post-peak strain softening response obtained from suction-controlled CTC tests above residual suction value with reasonable accuracy. Although, the proposed model captures initial compression followed by dilation volumetric response with reasonable accuracy, it needs some improvements to be able to capture volumetric response accurately over entire suction range.

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