Shear and volumetric straining response of çine sand

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2021-1-19
Korkusuz, Ahmet Can
The response of sandy soils under monotonic loading depends on size, shape and mineralogy of particles, fabric, stress and density states of mixtures. Researchers around the world have studied their local sands and calibrated their responses (e.g., Toyoura sand-Japan, Ottawa sand-Canada, Sacramento sand-US, Sydney sand-Australia, etc.). However, there are not many studies that have focused on regional sands from Turkey. This research study aims to introduce a local sand, Çine sand, to literature as a "standard sand" from Turkey. For this purpose, shear and volumetric straining responses of Çine sand samples were investigated by a series of consolidated undrained monotonic triaxial and oedometer tests. Specimens with relative densities of 25-47-60-70 and 85 %, were prepared by tapped funnel deposition and wet tamping methods and consolidated under 50 kPa, 100 kPa, 200 kPa ve 400 kPa cell pressures, followed by undrained shearing. Test results were presented by four-way plots, which enable the individual variations of axial load, cell pressure, pore water pressure, and axial deformation along with the progress of the stress paths relative to failure envelopes. On the basis of test results, linear and nonlinear elastic-perfectly plastic constitutive modelling parameters, including but not limited to stress and relative-density dependent modulus and effective stress based angles of shearing resistance, were estimated.Çine sands’ angles of shearing resistance values of 24.2˚-39.5° were observed. Triaxial modulus values fall in the range of ~10 and ~60 MPa. Similarly, samples with varying relative densities, prepared tapped funnel deposition method, were tested in a conventional oedometer device under stresses starting from ~23 kPa increasing up to ~29 MPa. During tests, unloading and reloading cycles were performed. Based on these test results, particle crushing-induced yield stresses of Çine sands along with their Cc, C values were estimated as ~1.3-3.1 MPa, ~1×10-2-25×10-2, and ~1×10-5–1×10-3, respectively. It was concluded that Çine sand exhibited Type B volumetric compression response as defined by Mesri and Vardhanabhuti (2009).
Citation Formats
A. C. Korkusuz, “Shear and volumetric straining response of çine sand,” M.S. - Master of Science, Middle East Technical University, 2021.