Soil stabilization

About: Soil stabilization is a research topic. Over the lifetime, 3161 publications have been published within this topic receiving 48437 citations.

Effects of pulverization on the strength and durability of highly active clay soils stabilized with lime and portland cement

Abstract: This paper presents the results of a laboratory investigation exploring the effects of varying degrees of pulverization, from laboratory-quality gradations to field gradations, on the strength and durability of highly plastic clay soils stabilized with lime and portland cement. Background information is presented on the mechanisms of stabilization and on previously reported studies of other materials. A 6-cu yd sample was used to provide 198 large specimens, which were tested in unconfined compression and wet-dry tests. Considerable differences were found in the strength of a highly active clay soil, depending on the gradations used to make specimens. Significant differences were found in the durabilities of specimens, depending on the stabilizer and the gradations used. Lime appears to be a more effective stabilizer for durability and portland cement more effective for strength, provided the gradation is fine enough. Recommendations, subject to further research, include longer curing times and the use of field gradations for all mix designs.

Centrifuge Modeling of Rocking Foundations on Improved Soil

Abstract: The nonlinear response of shallow foundations when subjected to combined loading has attracted the attention of the research engineering community over the last few decades, providing promising evidence for incorporation of such response in design provisions. Failure in the form of soil yielding or foundation uplifting may accommodate high ductility demand and increase the safety margins of the whole structure. However, increased permanent displacement and rotation may occur. This paper explores the concept of shallow soil improvement as a means to locally increase soil strength and thus limit rocking-induced settlement. Bearing in mind that the rocking mechanism is relatively shallow, failure may be contained in a soil layer of known properties that extends to a shallow depth beneath the foundation. The performance of a system in poor soil conditions, on an ideal soil profile, and on improved soil profiles was explored through a series of centrifuge tests at the Center for Earthquake Engineering ...

Improvement of loess characteristics using sodium alginate

Abstract: Loess often has poor engineering properties due to its loose accumulation and strong collapsibility. Therefore, improvement of the soil is necessary to meet the needs of engineering. In the current work, the improvement effect of sodium alginate added in different proportions to loess was studied. Limited water content test and particle size grading test were conducted to study the effect of sodium alginate on the basic physical parameters of soil. In addition, unconfined compressive strength test (UCS) and consolidated undrained test (CU) were used to analyze the changes in the mechanical properties of the soil after improvement. Additionally, permeation and disintegration tests were used to study the change in the soil’s water stability. What’s more, the microscopic mechanism of sodium alginate improved loess was also proposed based on the results of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that sodium alginate not only can change the liquid-plastic limit and particle size gradation of loess but also improve the strength, shear parameters, and water stability of loess. SEM and XRD studies revealed that sodium alginate changed the microstructure of the loess, formed a colloidal material to encapsulate the soil particles, filled the pores between soil particles, and caused aggregation of the clay material in the soil to form larger particle size via flocculation. These results show that sodium alginate can be used as a more environmental friendly and sustainable additive to replace the traditional soil stabilization additives, such as cement or lime to stabilize loess.

Geosynthetic subgrade stabilization – Field testing and design method calibration

Abstract: Geogrids and geotextiles are used routinely to stabilize weak subgrade soils during road construction. Typical subgrade stabilization applications are temporary haul roads or unpaved low-volume roads, but can also include paved roads built on poorer foundation materials. Full-scale test sections were constructed, trafficked and monitored to compare the relative operational performance of geosynthetics used as subgrade stabilization, as well as determine which material properties were most related to performance. Unpaved test sections were constructed using twelve geosynthetics consisting of a variety of geogrids and geotextiles. Multiple control test sections were also built to evaluate the effect that subgrade strength, base course thickness, and/or presence of the geosynthetic had on performance. Even though the geotextile materials used during this study showed good performance as subgrade stabilization, material properties associated with their performance was difficult to establish due to the limited number of test sections and lack of relevant tests to properly characterize these types of materials for this application. Using longitudinal rut as the primary indicator of performance, it was determined through a linear regression analysis that the stiffness of the geogrid junctions in the cross-machine direction correlated best with performance in this application and under these conditions. Using this knowledge, the design equation associated with the Giroud–Han method was calibrated to make geogrid junction stiffness in the cross-machine direction the primary property of the geosynthetic, thereby replacing geogrid aperture stability modulus. The calibration and verification of this method is described herein.