The study of shear and longitudinal velocity measurements of sands and cohesive soils
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2012
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| Online Access: | http://hdl.handle.net/1721.1/74496 |
| _version_ | 1811091993090064384 |
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| author | Marjanovic, Jana |
| author2 | John T. Germaine. |
| author_facet | John T. Germaine. Marjanovic, Jana |
| author_sort | Marjanovic, Jana |
| collection | MIT |
| description | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012. |
| first_indexed | 2024-09-23T15:11:12Z |
| format | Thesis |
| id | mit-1721.1/74496 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T15:11:12Z |
| publishDate | 2012 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/744962019-04-12T14:33:29Z The study of shear and longitudinal velocity measurements of sands and cohesive soils Marjanovic, Jana John T. Germaine. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Civil and Environmental Engineering. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012. Cataloged from PDF version of thesis. Includes bibliographical references (p. 185-189). This thesis evaluates some methods for the measurement of stiffness parameters of soils, with an emphasis on the use of bender element technology in obtaining the shear modulus. The experimental program consisted two primary stages. The beginning part of the experimentation was concerned with evaluating the behavior of bender elements, both free-standing and when applied to soil. For this case, experiments were performed on dry Ticino sand. It was concluded that the bender element tip geometry has a much greater impact than previously perceived, in particular with long, slender geometries sometimes creating directly-propagating compressional waves that interfere with the shear wave arrival detection. To reduce the uncertainty in signal interpretation, a specimen aspect ratio of 1 was adopted, with a minimum wavelength ratio of 2. The second part of the experimentation consisted of using bender elements on Boston Blue Clay, both intact samples as well as Resedimented Boston Blue Clay, created in the laboratory from processed powder. The results obtained from loading normally consolidated specimens were generally consistent and in good agreement with the literature. The unloading portion was observed to behaves differently as a function of maximum consolidation stress, with the shear modulus decreasing less during unloading as higher stress ranges are reached. In addition to the testing performed on soils, a parametric study was conducted on common materials including steel, aluminum, acrylic, and rubber in order to evaluate the results for stiffness parameters measured using extensometers, accelerometers, and ultrasonic P-wave transducers. With the conclusion of these experiments, the accelerometers were shown to have highly variable results, especially for shear wave velocity, while the other methods yielded relatively consistent, reliable results as compared to published values. Finally, a new design for a triaxial setup that enables integrated measurements of compressional and shear velocities in soil over a wide stress range is presented as groundwork for the characterization of the complete stiffness matrix of BBC. by Jana Marjanovic. S.M. 2012-10-26T19:01:54Z 2012-10-26T19:01:54Z 2012 2012 Thesis http://hdl.handle.net/1721.1/74496 813829933 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 189 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Civil and Environmental Engineering. Marjanovic, Jana The study of shear and longitudinal velocity measurements of sands and cohesive soils |
| title | The study of shear and longitudinal velocity measurements of sands and cohesive soils |
| title_full | The study of shear and longitudinal velocity measurements of sands and cohesive soils |
| title_fullStr | The study of shear and longitudinal velocity measurements of sands and cohesive soils |
| title_full_unstemmed | The study of shear and longitudinal velocity measurements of sands and cohesive soils |
| title_short | The study of shear and longitudinal velocity measurements of sands and cohesive soils |
| title_sort | study of shear and longitudinal velocity measurements of sands and cohesive soils |
| topic | Civil and Environmental Engineering. |
| url | http://hdl.handle.net/1721.1/74496 |
| work_keys_str_mv | AT marjanovicjana thestudyofshearandlongitudinalvelocitymeasurementsofsandsandcohesivesoils AT marjanovicjana studyofshearandlongitudinalvelocitymeasurementsofsandsandcohesivesoils |