Browsing by Subject "Dredged material"
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Item Analysis of dredge materials and crushed glass blends with uniaxial geogrids in pullout tests(2013-12) Lewis, Kemp Sloan; Zornberg, Jorge G.Being able to identify blended dredged material and crushed glass of different proportions as materials suitable for Mechanically Stabilized Earth walls could help the adoption of these materials in civil engineering thereby reducing the environmental impact of these waste materials. The objectives of this thesis include the following: Collect and organize data to facilitate material selection based on interaction properties with uniaxial geogrids; analyze the data for trends for varying percentages of crushed glass vs. dredged materials; compare the properties of different blends with those of a well-documented uniform sand; compare the pullout data with that of previous studies related to the presence of fines in the fill material; and compare the pullout data to that of previous studies on the effect of geogrid rib thickness. The main findings of this thesis study include the following: A blend of 80% crushed glass and 20% dredged material is a legitimate alternative backfill material for reinforced soil slopes. The use of 100% crushed glass as a fill material is not recommended due to glass particles embedding into the geogrid thereby reducing the tensile capacity of the geogrid. Blends with lower percentages of crushed glass and higher percentages of dredged material may be appropriate based on the requirements of individual designs. The increased thickness of the UX1700 geogrid over the UX1400 geogrid contributed to higher a pullout resistance for each combination of fill material and normal stress.Item Pullout evaluation of steel slag fines and dredged material blends with geogrids(2013-08) Somashekar Hanumasagar, Sangameshwar; Zornberg, Jorge G.Increasing quantities of dredged material (DM) from navigation waterways have led to a growing need to find alternative methods of disposal. Using this material in earthwork construction is a very attractive avenue, but poses concern of quality from a geotechnical standpoint. By blending DM with granular materials like industrial steel slag fines (SSF), studies have showed that the geotechnical properties of the mixture are greatly enhanced. If these materials can be proven to be competitive for use in earthwork construction, they would pose as an economically viable alternative, and would obviate the need for the relatively expensive conventional granular backfill. The scope of this project entailed the characterization of pullout interaction of SSF-DM blends in different proportions with Tensar uniaxial geogrids to determine an optimal combination for usage in earthwork construction. The media used for testing included the individual SSF and DM materials, and the 80/20, 50/50 and 20/80 blends mixed based on dry unit weights of the individual components. The SSF media comprised of particles smaller than 3/8 in. and classified as SW, while the DM was classified OH soil. Two Tensar uniaxial geogrids UX1400 and UX1700 were undertaken for the study. Pullout tests were conducted and performances of all the blends are compared with each geogrid at various normal pressures. Pullout loads and interaction coefficients give an idea of the quality of the interaction, and are studied in this thesis. Also, various variables that could potentially affect the pullout interaction are identified and investigated. Results show remarkably high pullout resistances for the 100% SSF and 80/20 SSF/DM media, and high interaction coefficients indicating excellent pullout interaction, even better than conventional sands. It was also clear that the dredged material exhibits very poor pullout interaction with geogrids. The 50/50 and the 20/80 SSF/DM media were significantly lower than the 80/20 SSF/DM blend in terms of quality of pullout interaction, but still higher than the 100% DM. The results observed with the 80/20 SSF/DM blend show that it is a suitable backfill material and also poses to be a very competitive and cost-effective alternative to be used in earthwork construction.Item Pullout evaluation of uniaxial geogrids embedded in dredged material(2013-05) Kondo, Jacob Robert; Zornberg, Jorge G.With the ever increasing need for MSE walls, the study of the interaction between soil and geosynthetics has become increasingly relevant. New concepts are constantly being researched, including the use of industrial byproducts as alternative backfill materials. The idea that byproduct material could somehow be a suitable fill for these MSE walls may spark new opportunities. One such byproduct being researched is dredged material. The suitability of dredged material as a backfill would not only contribute to lower construction costs, but would also benefit local confined disposal facilities looking to reduce their already overflowing dredged material accumulation. This thesis further considers the use of dredged material by evaluating its interface shear strength with uniaxial geogrids. A series of laboratory pullout tests were conducted using two types of uniaxial geogrids (UX1400 and UX1700) embedded in three different soil types (Monterey Sand and two different dredged materials). The laboratory results are used to examine the effect on the coefficient of interaction of the various parameters governing the pullout resistance. The results of this study show that: (1) the presence of adhesion to characterize the soil-reinforcement interface shear strength causes a decrease in the coefficient of interaction with increasing normal stress, (2) the reinforcement length of the geogrid was found not to affect the coefficient of interaction; provided that boundary effects are minimized, (3) the dredged material, tested wet of optimum, showed a response consistent with an undrained behavior, which produced pullout resistances significantly lower than that of the Monterey Sand, (4) the coefficient of interaction for the UX1700 was comparatively higher than that for the UX1400; however the differences obtained when testing Monterey Sand were similar to those obtained when testing the dredged materials.