scholarly journals Influence of effective stress on swelling pressure of expansive soils

2016 ◽  
Vol 9 ◽  
pp. 14016
Author(s):  
Wiebke Baille ◽  
Linzhi Lang ◽  
Snehasis Tripathy ◽  
Tom Schanz
Keyword(s):  
Effective Stress ◽  
Expansive Soils ◽  
Swelling Pressure

scholarly journals Combined effect of mineralogical and chemical parameters on swelling behaviour of expansive soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bendadi Hanumantha Rao ◽  
Peddireddy Sreekanth Reddy ◽  
Bijayananda Mohanty ◽  
Krishna R. Reddy
Keyword(s):  
Expansive Soils ◽  
Research Work ◽  
Swelling Pressure ◽  
Combined Effect ◽  
Practical Significance ◽  
Chemical Compositions ◽  
Chemical Parameters ◽  
Swelling Behaviour ◽  
Mineral Contents ◽  
Swelling Properties

AbstractMicrolevel properties such as mineralogical and chemical compositions greatly control the macro behaviour of expansive soils. In this paper, the combined effect of mineral (i.e. montmorillonite, MMC) and chemical contents (i.e. Ca and Na in their total (T), leachable (L) and exchangeable form (CEC)) on swelling behaviour is investigated in a comprehensive way. Several 3-dimensional (3D) graphs correlating MMC and Ca/Na ratio, together, with swelling property (swelling potential, Sa, and swelling pressure, Sp) are developed. 3D plots, in general, portrayed a non-linear relationship of Sa and Sp with MMC and Ca/Na ratio, together. It is hypothesized that swelling initially is triggered by chemical parameters due to their quick and rapid ionization capability, but the overall swelling phenomenon is largely controlled by MMC. It is importantly found that expansive soils are dominant with divalent Ca++ ions up to MMC of 67% and beyond this percentage, monovalent Na+ ions are prevalent. From the interpretation of results, the maximum Sa of 18% and Sp of 93 kPa is measured at MMC of 43%, (Ca/Na)T of 10–14 and (Ca/Na)L of 2–7. It is concluded from study that total CEC + MMC for determining Sa and (Ca/Na)T + MMC for determining Sp are superior parameters to be considered. The findings of the study also excellently endorsed the results of Foster32, who stated that ionization of Na or Ca depends on the constituent mineral contents. The findings presented herein are unique, interesting and bear very practical significance, as no earlier research work reported such findings by accounting for chemical and mineralogical parameters impact, in tandem, on swelling properties.

Comparison of three inclusions in reducing lateral swelling pressure of expansive soils

2018 ◽  
Vol 25 (5) ◽  
pp. 481-493 ◽  
Author(s):  
L.-L. Wan ◽  
W.-L. Zou ◽  
X.-Q. Wang ◽  
Z. Han
Keyword(s):  
Expansive Soils ◽  
Swelling Pressure

scholarly journals Swelling phenomena and effective stress in compacted expansive clays

2016 ◽  
Vol 53 (1) ◽  
pp. 134-147 ◽  
Author(s):  
David Mašín ◽  
Nasser Khalili
Keyword(s):  
Pore Water ◽  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Swelling Pressure ◽  
Constitutive Modelling ◽  
Dry Density ◽  
Expansive Clay ◽  
Experimental Database ◽  
Clay Aggregates

The central aim of this paper is to discuss the applicability of the effective stress principle as defined by Terzaghi (total stress minus pore-water pressure) to predict the behaviour of expansive clay aggregates. Phenomena occurring between individual clay minerals are reviewed first at the molecular level obtained in the colloid science research. In particular, it is noted that, for interparticle distances higher than approximately 1.5 nm, the pore-water pressure in the bulk equilibrium solution forms an additive component of the interparticle disjoining pressure. It is concluded that for these distances Terzaghi’s effective stress principle should be adequate to describe the clay behaviour. To support these developments, an extensive experimental database of nine different sodium and calcium bentonites available in the published literature was analysed. With the aid of double structure constitutive modelling, procedures were developed to extract information about the behaviour of clay aggregates from the experimental measurements. It was then shown that unconfined water retention curves, swelling pressure tests, swelling under constant load tests, and mechanical unloading tests are all uniquely related in terms of the dependency of dry density (or void ratio) of clay aggregate versus mean effective stress. By considering reversibility of aggregate behaviour and full saturation of aggregates, this implies that the effective stress principle is a valid way of predicting expansive clay aggregate volumetric deformation.

Increasing pull-out capacity of granular pile anchors in expansive soils using base geosynthetics

2000 ◽  
Vol 37 (4) ◽  
pp. 870-881 ◽  
Author(s):  
B R. Phani Kumar ◽  
N Ramachandra Rao
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Ground Movement ◽  
Anchor Plate ◽  
Pull Out ◽  
Swelling Soil ◽  
Granular Pile ◽  
Load Rate ◽  
Uplift Load

Granular pile anchors are innovative and effective in resisting the uplift pressure exerted on the foundation by a swelling expansive soil. In a granular pile anchor, the foundation is anchored at the bottom of the granular pile to an anchor plate with the help of a mild steel rod. This renders the granular pile tension-resistant and enables it to offer resistance to the uplift force exerted on the foundation by the swelling soil. This resistance to uplift or pull-out load depends mainly upon the shear parameters of the pile-soil interface and the lateral swelling pressure of the soil, which confines the pile radially and prevents it from being uplifted. The resistance to uplift can be increased by placing a base geosynthetic above the anchor plate so that it forms an integral part of the granular pile anchor. The increase in resistance is due to the friction mobilized between the geosynthetic and the confining media when the uplift load acts on the pile and the geosynthetic moves along with the pile. Hence it depends on the friction between the geosynthetic and the confining media and the area and stiffness of the geosynthetic. This paper discusses the effects of these parameters on pull-out load, rate of heave, and relative ground movement near the pile surface.Key words: expansive soil, granular pile anchor, base geosynthetic, ground movement, rate of heave, pull-out load.

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