Discrete particle simulation of particulate systems: A review of major applications and findings

Simple reliability analyses, involving neither complex theory nor unfamiliar terms, can be used in routine geotechnical engineering practice. These simple reliability analyses require little effort beyond that involved in conventional geotechnical analyses. They provide a means of evaluating the combined effects of uncertainties in the parameters involved in the calculations, and they offer a useful supplement to conventional analyses. The additional parameters needed for the reliability analyses—standard deviations of the parameters—can be evaluated using the same amount of data and types of correlations that are widely used in geotechnical engineering practice. Example applications to stability and settlement problems illustrate the simplicity and practical usefulness of the method.

Factors of safety and reliability in geotechnical engineering

Chemical and microbial remediation of hexavalent chromium from contaminated soil and mining/metallurgical solid waste: a review.

Remediation technologies for heavy metal contaminated groundwater.

Keywords: Mecanique des sols ; Drainage ; Ecoulement souterrain Reference Record created on 2004-09-07, modified on 2016-08-08

Applications of soil physics.

Specimens prepared from eight natural clayey soils used for clay liners and covers were subjected to cycles of wetting and drying. Volumetric shrinkage strains were recorded during drying. Specimens in which cracks formed during drying were subjected to hydraulic conductivity testing. Results of the study indicate that volumetric shrinkage strains are influenced by soil properties and compaction conditions. Volumetric shrinkage strain increased with increasing plasticity index and clay content, and as the compaction water content increased or decreased relative to optimum water content. Volumetric shrinkage strain decreased with increasing compactive effort. Specimens with the largest volumetric shrinkage strains typically contained the largest number of cracks. Hydraulic conductivity testing indicated that cracking of the specimens resulted in an increase in hydraulic conductivity, sometimes as large as three orders of magnitude.

Effect of Desiccation on Compacted Natural Clays

Evaluating the hydraulic conductivity of GCLs permeated with non-standard liquids

The influence of single-species salt solutions of various concentration, cation valence, and pH on swelling and hydraulic conductivity of nonprehydrated GCLs was examined. At similar concentration, swell was largest with NaCl, KCl, and LiCl solutions (monovalent cations Na+, K+, and Li+) and smallest with LaCl3 solutions (trivalent cation La3+). Intermediate swell volumes were obtained with divalent solutions (CaCl2, MgCl2, ZnCl2, and CuCl2). Analogous results were obtained from hydraulic conductivity tests. GCL specimens permeated with solutions containing divalent or trivalent cations had higher hydraulic conductivity than GCLs permeated with monovalent solutions or deionized water, unless the divalent or trivalent solutions were very dilute (≤0.01 M). Hydraulic conductivity increased as the concentration increased, and at high concentration (1 M) only small differences existed between hydraulic conductivities measured with all solutions. Swelling and hydraulic conductivity were related to size of the h...

Hydraulic conductivity and swelling of nonprehydrated gcls permeated with single-species salt solutions

The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce sand. Direct shear tests were conducted on mixtures of dry sand and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, sand matrix unit weight, shred content, shred length, and shred orientation. From results of the tests, three significant factors affecting shear strength were identified: normal stress, shred content, and sand matrix unit weight. A model for estimating the strength of reinforced soils was also evaluated to determine its applicability to mixtures of sand and tire shreds. When the model is calibrated using results from one shred content, it may be useful for estimating the friction angle for other shred contents. In all cases, adding shredded tires increased the shear strength of sand, with an apparent friction angle (ϕ′) as large as 67° being obtained. Shred content and sand matrix unit weight were the most significan...

Sand Reinforced with Shredded Waste Tires

Soil liners have traditionally been compacted in the field to a minimum dry unit weight over a specified range in water content. This approach evolved from the practice for structural fills for which strength and compressibility are of primary concern. With soil liners, hydraulic conductivity is usually of paramount importance. Hence, the approach used to ensure adequate strength and permissible compressibility is not necessarily applicable to the construction of soil liners. Data are presented to show that the water content-density criteria for compacted soil liners can be formulated in a manner that is different from the approach currently used by many engineers. The recommended approach is based on defining water content-density requirements for a broad, but representative, range of compactive energy, and relating those requirements to hydraulic conductivity and other relevant factors. A case history illustrates the recommended procedure and its implementation. Hydraulic conductivity measurements were performed on three soils to develop an “acceptable zone” on the compaction curve that was used for quality control during construction. As a result of implementing the recommended procedure, construction operations were significantly accelerated.

Craig H. Benson

Papers

Effect of Desiccation on Compacted Natural Clays

Evaluating the hydraulic conductivity of GCLs permeated with non-standard liquids

Hydraulic conductivity and swelling of nonprehydrated gcls permeated with single-species salt solutions

Sand Reinforced with Shredded Waste Tires

Water Content-Density Criteria for Compacted Soil Liners