A simplified swelling pressure models for expansive soils based on a nonlinear fitting function

2016 ◽  
pp. 881-885
Author(s):  
C Yan ◽  
Z Huang ◽  
X Huang
Keyword(s):  
Expansive Soils ◽  
Swelling Pressure ◽  
Nonlinear Fitting

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 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

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.

scholarly journals Swelling Pressure of Double-Expansive Material and Its Active Support Effect for Coal Seam Gas Drainage Borehole

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhiming Wang ◽  
Yuning Sun
Keyword(s):  
Coal Seam ◽  
Field Tests ◽  
Swelling Pressure ◽  
Support Effect ◽  
Coal Seam Gas ◽  
Borehole Stability ◽  
Gas Drainage ◽  
Nonlinear Fitting ◽  
Improved Stability ◽  
Drainage Borehole

To improve coal seam gas drainage performance, we developed a double-expansive (DE) material to seal the borehole. The swelling process of this material includes an initial swelling stage and a secondary swelling stage. We studied the swelling pressure properties of the DE material under four constraint conditions using a self-made swelling test device. Further, the active support effect of the DE material on the borehole was analyzed by simulating borehole stability with COMSOL Multiphysics software. The results exhibit the following: (1) The swelling pressure of the DE material exhibits time-dependent behavior, and the mathematical relationship between the swelling pressure and time can be obtained by nonlinear fitting. (2) The radial swelling potential is principally formed during the secondary swelling stage, providing the main active support on the radial constraint. (3) The active support imposed on the hole wall can prevent the extension of plastic and damage regions around the borehole, for improved stability of the gas drainage borehole. Finally, field tests demonstrate improved gas drainage performance of the borehole sealed by the DE material compared to a conventional sealing material.

Measurement of swelling pressure: direct method versus indirect methods

2011 ◽  
Vol 48 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Kamil Kayabali ◽  
Saniye Demir
Keyword(s):  
Expansive Soils ◽  
Direct Method ◽  
Swelling Pressure ◽  
Expansive Clay ◽  
Swelling Properties ◽  
Indirect Methods ◽  
Natural Soils ◽  
Considerable Research ◽  
Free Swell ◽  
Swell Pressure

Light structures including highways and railroads built over potentially expansive clay soils may suffer damage from swelling. Considerable research has been done in an attempt to characterize swelling properties of expansive soils. Although direct measurement of swelling pressure is relatively straightforward, it has not drawn much interest. The present study attempts to measure swelling pressure directly. We call experimental techniques for swelling pressure other than this direct method the indirect methods. Some indirect methods require more than one soil sample and that all samples be identical. However, natural soils may not always provide identical samples. Therefore, reconstructed identical soil samples produced from natural soils were used in the present study. For comparison, the restricted swell, swell-consolidation, double oedometer, and zero swell tests were employed as indirect methods. While the restricted swell test slightly underestimated swell pressure, swell-consolidation and zero swell tests overestimated it. The double oedometer test did not provide swell pressures correlatable with those found using the direct method. Free swell data correlated reasonably well with swell pressure data from the direct method, so an empirical form was established from which swell pressure can be easily estimated.

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