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Unformatted text preview: Florida International University Department of Civil and Environmental Engineering CEG-5065C Soil Dynamics Laboratory Professor Luis A. Prieto-Portar PhD, PE, SE. Laboratory Report #1 The Unconfined Compression Test (ASTM D-2166) (AASHTO T-208) Performed on 29 October 2009 Team Members: Member Attendance Assignment Completed 1. 2. 3. 4. 5. 6. 7. 1) Introduction: The objective of this experiment is to inexpensively measure the approximate shear strength of a cohesive soils. This test is only possible upon samples that have been obtained in the field in an intact state, that is, they have no cracks or fissures. Otherwise, the samples should be tested via a triaxial cell. The tests are performed on tube-recovered clay samples. In essence, this is a simple experiment, that consists of trimming a sample to a proper L/d ratio, placing it into a compression device and measuring the load-to-deformations. The L/ d ratio should be 2< L/d < 3. The only load on the sample is the (vertical) major principal stress σ 1 since the (horizontal) minor principal stress σ 3 = 0. A Mohr circle reveals that the undrained shear strength s u which is also known as the “cohesion” c , 2 u u q s c = = where q u is the symbol for the unconfined compressive strength of the soil. The angle of internal friction φ = 0. These special conditions lead some engineers to call this test an “unconsolidated undrained” test, or UU for short. The “undrained” name is a way of dignifying the un-confined state ( σ 3 = 0), which although crude, is quick and economical....
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- Fall '09
- Compressive strength, Mohr Circle, unconfined compression test