Swell and shrinkage characterizations of unsaturated expansive clays from Texas

Abstract

Expansive soils have long been recognized as problematic because they cause failure to civil structures constructed above them. The main problem of these soils can be attributed to poor understanding of the volume changes caused by moisture fluctuations. Current swell and shrinkage characterization models are limited by both the lack of standardized tests and tests that employ volume changes in uniaxial direction. In the present research, a comprehensive laboratory investigation was undertaken to study the volume change related swell-shrinkage behaviors of five different types of expansive clayey soils sampled from various regions in Texas, USA. Extensive experimental programs consisting of basic, chemical and mineralogical soil properties were first determined. Three-dimensional free swell and shrinkage tests were performed on all soils at various compaction moisture content conditions. Soil water characteristic curves (SWCCs) of all test soils were determined by studying the suction potentials of these soils over a wide range of moisture contents. Volume change measurements of soils showed a good correlation with soil properties, including plasticity and soil compaction properties. SWCC results also showed a clear variation in SWCC profiles of soils with respect to soil plasticity. Overall, a large database of soil properties was developed and is presented here. It includes physical and mineralogical properties, and engineering test results including swell, shrinkage and SWCCs. This is an author-produced, peer-reviewed version of this article. The final, definitive version of this document can be found online at Engineering Geology, published by Elsevier. Copyright restrictions may apply.

Clays of Different Plasticity as Materials for Landfill Liners in Rural Systems of Sustainable Waste Management

“…Hence, the long-term performance of a landfill liner, limiting possible streams of pollution, is, in our opinion, strongly reliant on three interrelated characteristics of the applied compacted earthen material, related directly to its particle composition, mineralogy, Atterberg limits, plasticity and compaction initial water content: hydraulic conductivity under natural conditions and after compaction, swell-shrinkage characteristics and, finally, the ability of soil/substrate to sustain its hydraulic conductivity after cyclic changes of saturation, resulting in repeated shrinkage and swelling, commonly leading to serious cracking [24,34,35,38,40,41,[45][46][47]. In our opinion, it is also important that the above-mentioned characteristics are easy to determine and measure, without the sophisticated laboratory and field equipment and may be easily understood.…”

Innovative ground improvement techniques for expansive soils

“…Lime/cement additive stabilization technique is considered to be very effective for reducing swell/shrink potential, plasticity, strength and increasing workability of expansive soils [4,22,33]. The most substantial improvements in these properties are seen in moderately to highly plastic clays [10,16,32], Puppala et al [28].…”

Swell and shrinkage strain prediction models for expansive clays

“…In addition, comprehensive laboratory physical and engineering properties of the four test site soils were already available, as reported by Puppala et al (2013), and these results were used in both the analytical and numerical models for the predictions of vertical swell strains.…”

“…Both models used basic soil properties, including soil matric suction parameters, from Puppala et al (2013) for the prediction analysis. Field moisture contents measured by TDT probes were then used to estimate moisture movements during seasonal changes, and this data was used in the present correlation for swell strain predictions.…”

“…The first paper by Puppala et al (2013) describes a comprehensive summary of testing programs and test results determined from five soil types sampled from various parts of Texas. All five soils, containing different amounts of expansive clay minerals, were subjected to swell, shrinkage and suction-based characterization tests.…”