Expansive soils are a worldwide problem that possesses various challenges for civil engineers. With increasing water content, they exhibit excessive volume changes, resulting in large horizontal and vertical stresses to the structures located or buried in these regions. The most common method to minimize this effect is to replace these types of clays around the proposed structure with nonexpansive soils. For the cases needing larger volume of replacement, either sidewalls or the foundations must be designed to cater for the anticipated pressures or a suitable improvement technique shall be applied in place.
In this experimental study, it is intended to investigate the possible positive effects of trenches backfilled with granular material such as crushed stone or rock on the improvement of swell parameters of expansive soils. Thin-wall oedometer tests, conventional oedometer tests and larger size tests with moulds were performed on artificially compacted untreated and granular fill treated samples for this purpose. The trenches were modeled by opening a hole with a diameter that satisfies the predicted percent trench content at the center of the soil samples, which was then backfilled with granular material. Modified thin-wall oedometer tests were performed to measure the lateral swell pressures of both untreated and treated samples, whereas the conventional oedometer tests and tests on samples placed in moulds were performed to measure the vertical swell parameters of soils. It was observed that both the vertical swell percentages as well as the lateral swell pressures reduced considerably as the volume of granular material filled trench was increased. The treatment was observed to be more remarkable under the surcharge effect of a light weight structure or a fill placed on top.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12614886/index.pdf |
| Date | 01 September 2012 |
| Creators | Hergul, Timucin |
| Contributors | Cokca, Erdal |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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