Civil and Environmental Engineering Commons^™

Effect Of Particle Swelling On Hydraulic Performance And Meso-Mechanism Of Geosynthetic Clay Liners, Juan Hou, Jin-Bang Zhang, Yin-Yu Sun, Rui Sun, Fei-Yu Liu

Rock and Soil Mechanics

The hydraulic performance of geosynthetic clay liners (GCL) is closely related to the swelling characteristics of the bentonite particles and the resulting porous medium. However, there currently needs to be more analysis at the mesoscopic level to understand the permeating mechanisms. A numerical model using COMSOL was developed to study the effects of particle swelling on the effective porosity, tortuosity, and hydraulic conductivity of GCL under deionized water actions. The results demonstrate that the swelling of bentonite particles is a crucial factor influencing the effective porosity, tortuosity, and hydraulic conductivity of GCL. Particle swelling significantly affects the width and number …

A Rapid Determination Method Of Hydraulic Conductivity In Full Suction Range, A-Qiang Liu, Xu Li, Yan Liu, Zhi-Yuan Zhang

Rock and Soil Mechanics

The hydraulic conductivity function of unsaturated soil spans several orders of magnitude. Traditional measurement methods often take several months, and it is difficult to measure the hydraulic conductivity in the full suction range. In order to realize the rapid measurement of hydraulic conductivity in the full suction range, the wetting front advancing method is combined with the instantaneous profile method (here referred to as the combined determination method) in this study. A self-developed soil column infiltration device was used to measure the hydraulic conductivity of Qinghai silty clay in the full suction range under different dry densities. The test results …

Thermo-Hydro-Mechanical Characterization Of Ottawa Sand And Kaolin Clay Through Experimental Models., Mohammad Joshaghani

Electronic Theses and Dissertations

Recent advances in energy geotechnics and increased utilization of ground source heat pump systems (e.g., geothermal boreholes and energy y piles) and energy geo-structures require improving the understanding of the thermo-hydro-mechanical behavior of soil. Energy geo-structures consist of above-ground facilities, buried structures, and the soil surrounding the buried structure. A buried structure transfers the energy between the ground and above-ground facilities. Energy transfer between above-ground facilities and the soil will cause temperature changes in soil and this will affect soil hydro-mechanical properties. The changes in soil temperature can also significantly alter the soil-structure interaction and its mechanical strength. Soil temperature …

Permeability Evolution Of Compacted Clay During Triaxial Compression, Gang Wang, Lin-Yi Wei, Xing Wei, Jian-Min Zhang

Rock and Soil Mechanics

Triaxial seepage tests were conducted on the core-wall clay of a high rock-fill dam to investigate the change of hydraulic conductivity with axial strain. It was found that the compaction density and confining pressure were the two main factors influencing the change of hydraulic conductivity during triaxial compression. When the current confining pressure was greater than the pre-consolidation pressure of a compacted specimen, the specimen kept being compressed and became denser during the compression process, resulting in a decreasing trend in its hydraulic conductivity until it eventually reached a stable state. On the other hand, if the current confining pressure …

Physical Modeling Of Flow Nets In Groundwater And Determination Of Hydraulic Conductivity, Hannah Nicholas, Moses Karakouzian

AANAPISI Poster Presentations

The goal of this study is to physically model the paths that water particles take through soil, and estimate hydraulic conductivity for several soil configurations. Water paths, or flow lines, are shown by injecting dye into sand contained in a rectangular acrylic glass tank with a vertical barrier in the center; water is poured on one side of the tank and a pump is used to maintain constant head loss. If flow lines are formed, a flow net is to be drawn using photos of the tank and hydraulic conductivity is to be calculated.

This project consists of four phases: …

A Study On Chemical Grouting Of Quartz Sand, Bingfeng Xue

Electronic Thesis and Dissertation Repository

Chemical grouting has been used in engineering projects for decades. The primary objectives of chemical grouting in geotechnical engineering projects are to increase the soil strength, to decrease the soil permeability, and to control deformations of in-situ soil. In the design and applications of chemical grouting, laboratory testing of chemical grouted samples is an important step for the feasibility assessment.

The advantages of sodium silicate grout include high penetrability, flexible set times, and environmentally friendly, which makes it one of the most employed grouts in applications. Recently, an innovative sodium silicate, which has the silica to alkali ratio of 4.5 …

Development Of A Hydraulic Conductivity Placement Window Using Centrifuge Techniques, Greg Thomas

Civil Engineering Undergraduate Honors Theses

A centrifuge soil testing device, currently operated by researchers at the University of Arkansas, was used to develop a technique to determine a hydraulic conductivity placement window. The purpose of this research was to develop a placement window by means of a centrifuge instead of by means of a panel board. Soil specimens were created at standard PRcotor energy and at 50 percent of Standard Proctor energy at -3 percent of optimum, -1.5 percent of optimum, two specimens at optimum, +1.5 percent of optimum, and +3 percent of optimum water content. Values of hydraulic conductivity for the respective specimens were …

Experimental Study Of Hydraulic Conductivity Of A Soil-Bentonite Cutoff Wall, Landon Crawford Barlow

Master’s Theses

Soil-bentonite (SB) cutoff walls are commonly employed in the US to control groundwater flow and subsurface contaminant migration. In these applications, both the short-term (as built) integrity of the barrier and the potential for degradation in the integrity of the barrier over time are of critical importance. Although many laboratory studies have been conducted to investigate the performance of SB cutoff walls as hydraulic barriers and the various factors affecting this performance, field investigations are scarce. With support from the National Science Foundation, a 200 m long, 7 m deep, and 0.9 m wide SB cutoff wall has been designed, …

Assessment Of Backfill Hydraulic Conductivity In An Instrumented Soil-Bentonite Cutoff Wall, Landon Barlow, Michael A. Malusis

Faculty Conference Papers and Presentations

The objective of this paper is to present a comparison of measured hydraulic conductivities (k) for soil-bentonite (SB) backfill within a 60-m-long section of a 200-m-long, 7-m-deep cutoff wall constructed and instrumented for studying SB backfill properties and variability at the field scale. Backfill k was measured using flexible-wall tests (70-mm diameter) on remolded specimens prepared from surface grab samples collected during construction; flexible-wall tests on undisturbed specimens collected from the wall; larger-scale rigid-wall tests (150-mm diameter) on remolded specimens prepared from grab samples; and slug tests conducted within the wall. Applied effective stresses in the laboratory tests …

Electromagnetically Induced Alteration Of Hydraulic Conductivity Of Coarse-Grained Soils For Geotechnical Applications, Rakesh Acharya

Boise State University Theses and Dissertations

Electromagnetic (EM) waves of various power levels and frequencies can be used to alter the hydraulic conductivity of soil with minimal heat generation. The result can lead to a number of potential applications such as contamination remediation and liquefaction mitigation. In this research, the possibility of radio-frequency (RF) waves’ effect on the excess pore-water pressure (EPWP) generation and hydraulic conductivity of coarse-grained soils has been investigated.

Impact tests were performed on glass beads to examine the effect on the generation of EPWP due to RF waves. These tests were performed on a rigid box made of Plexiglas. The impacts were …

Time-Dependent Behaviour Of Micro-Tunneling Construction In Queenston Shale, Hayder Mohammed Salim Al-Maamori

Electronic Thesis and Dissertation Repository

The Queenston shale among other shales from southern Ontario exhibits time-dependent deformation behaviour. This behaviour is manifested in the form of volume increase which can cause damages to the hosted underground structures. The time-dependent deformation of rocks can cause cracks in the springline of tunnels, wall inward movement, roof spalling and floor heave, which requires costly remedial measures. The expansion of the existing infrastructures in southern Ontario requires construction techniques, such as micro-tunneling to build new tunnels and pipelines under the existing structures with minimal impact to these structures and to the environment. However, adopting this technique in swelling rocks, …

Chemical Compatibility Of Model Soil-Bentonite Backfill Containing Multiswellable Bentonite, Michael A. Malusis, Matthew D. Mckeehan

Faculty Journal Articles

The objective of this study was to evaluate the chemical compatibility of model soil-bentonite backfills containing multiswellable bentonite (MSB) relative to that of similar backfills containing untreated sodium (Na) bentonite or a commercially available, contaminant resistant bentonite (SW101). Flexible-wall tests were conducted on consolidated backfill specimens (effective stress =34.5 kPa) containing clean sand and 4.5–5.7% bentonite (by dry weight) using tap water and calcium chloride (CaCl2) solutions (10–1,000 mM) as the permeant liquids. Final values of hydraulic conductivity (k) and intrinsic permeability (K) to the CaCl2 solutions were determined after achieving both short-term termination criteria as …

Compressibility And Hydraulic Conductivity Of Zeolite-Amended Soil-Bentonite Backfills, Catherine Hong, Charles D. Shackelford, Michael A. Malusis

Faculty Journal Articles

The effect of zeolite amendment for enhanced sorption capacity on the consolidation behavior and hydraulic conductivity, k, of a typical soil-bentonite (SB) backfill for vertical cutoff walls was evaluated via laboratory testing. The consolidation behavior and k of test specimens containing fine sand, 5.8 % (dry wt.) sodium bentonite, and 0, 2, 5, or 10 % (dry wt.) of one of three types of zeolite (clinoptilolite, chabazite-lower bed, or chabazite-upper bed) were measured using fixed-ring oedometers, and k also was measured on separate specimens using a flexible-wall permeameter. The results indicated that addition of a zeolite had little impact …

Hydraulic Conductivity Of Model Soil-Bentonite Backfills Subjected To Wet-Dry Cycling, Michael A. Malusis, Jeffrey C. Evans, Seungchoel Yeom

Faculty Journal Articles

The potential for changes in hydraulic conductivity, k, of two model soil-bentonite (SB) backfills subjected to wet-dry cycling was investigated. The backfills were prepared with the same base soil (clean, fine sand) but different bentonite contents (2.7 and 5.6 dry wt %). Saturation (S), volume change, and k of consolidated backfill specimens (effective stress = 24 kPa) were evaluated over three to seven cycles in which the matric suction, Y_m, in the drying stage ranged from 50 to 700 kPa. Both backfills exhibited susceptibility to degradation in k caused by wet-dry cycling. Mean values of …

Investigation Of The Geotechnical Properties Of Municipal Solid Waste As A Function Of Placement Conditions, Wilson W. Wong

Master's Theses

An investigation of the variability of engineering properties of municipal solid waste as a function of placement conditions was conducted. Limited data have been reported for the engineering properties of municipal solid waste (MSW) as a function of placement conditions. Wastes have high variability of engineering properties due to heterogeneity in composition and component size; influence from time based effects; and presence of compressible solids. Control of moisture content of MSW at the time of waste placement provides opportunity for increased capacity at a given landfill site due to higher compacted unit weight as well as for control of other …