The mechanical behavior of normally consolidated soils as a function of pore fluid salinity
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | eng |
| Published: |
Massachusetts Institute of Technology
2012
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/1721.1/73793 |
| _version_ | 1811091284854571008 |
|---|---|
| author | Horan, Aiden James |
| author2 | John T. Germaine. |
| author_facet | John T. Germaine. Horan, Aiden James |
| author_sort | Horan, Aiden James |
| collection | MIT |
| description | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012. |
| first_indexed | 2024-09-23T15:00:03Z |
| format | Thesis |
| id | mit-1721.1/73793 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T15:00:03Z |
| publishDate | 2012 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/737932019-04-12T14:33:21Z The mechanical behavior of normally consolidated soils as a function of pore fluid salinity Horan, Aiden James 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. 339-344). Pore fluid salinities in the Gulf of Mexico area can reach levels of 250 grams of salt per liter of pore fluid (g/1). It is now necessary to determine the effect that this salinity level can play on the mechanical behaviors of marine sediments. An extensive laboratory testing program involving Constant Rate of Strain (CRS) and Ko consolidated undrained shear in compression triaxial testing (CKoUC) was undertaken. Soil specimens reached axial effective stresses of 10 MPa with a select few reaching 40 MPa in a modified CRS device. All triaxial tests were performed in a low pressure triaxial apparatus. The shear behavior of all soils was obtained in the normally consolidated region. Several reverse leaching tests were performed in the CRS cell whereby high salinity pore water was flushed through a low salinity soil while consolidation was halted. The majority of testing was performed on resedimented specimens using several different soils from around the world. These include Boston Blue Clay (BBC), London Clay, Gulf of Mexico soil and sodium montmorillonite. Several derivatives of BBC were resedimented including BBC which had some of its natural salt removed via leaching, and also BBC which had its fabric completely dispersed using sodium hexametaphosphate. Pore fluid salinities ranging from 0 (distilled water) to 256 g/l were used when resedimenting these soils. The resedimented BBC test results were compared to intact BBC soil which was recovered from below the MIT campus. The results show that BBC and London Clay are relatively insensitive to increases in pore fluid salinities up to 256 g/l. This sensitivity can be increased by leaching some of the natural salt from the soil and then resedimenting to different pore fluid salinities. The strength characteristics of BBC over this large salinity range also remain fairly constant with the only differences being observed in leached BBC. It was also seen that the strain to failure for resedimented BBC is half that which is required for intact soil with all other measured parameters being similar. Interesting observations were seen in relation to how the fabric of BBC evolves with an increase in stress level and a theory of how floc breakage occurs at a given stress level is proposed. A potential crude method of quantifying the contribution of electro-chemical forces to a soils strength is also suggested by Aiden James Horan. S.M. 2012-10-10T15:45:50Z 2012-10-10T15:45:50Z 2012 2012 Thesis http://hdl.handle.net/1721.1/73793 810458408 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 354 p. application/pdf nm----- Massachusetts Institute of Technology |
| spellingShingle | Civil and Environmental Engineering. Horan, Aiden James The mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| title | The mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| title_full | The mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| title_fullStr | The mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| title_full_unstemmed | The mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| title_short | The mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| title_sort | mechanical behavior of normally consolidated soils as a function of pore fluid salinity |
| topic | Civil and Environmental Engineering. |
| url | http://hdl.handle.net/1721.1/73793 |
| work_keys_str_mv | AT horanaidenjames themechanicalbehaviorofnormallyconsolidatedsoilsasafunctionofporefluidsalinity AT horanaidenjames mechanicalbehaviorofnormallyconsolidatedsoilsasafunctionofporefluidsalinity |