User:Vibes369/Notes

The Oedometer Test is a Geotechnical Engineering test that measures a soil's consolidation properties.

Two types

1. Incremental Loading (IL) test
2. Constant Rate of Strain (CRS) test

Do a Pros/Cons section for IL vs CRS test

In confined layers of soil, vertical compression takes place only through a decrease in void ratio (link)(113). To replicate the lateral confinement in the lab, a rigid confining ring is used (113). Drainage is allowed by placing rigid porous stones on the top and bottom of the sample (113).

An Oedometer Test is a Geotechnical Engineering test that measures a soil's consolidation properties. Oedometer Tests are performed by applying different loads to a soil sample and measuring the deformation response. The results from these tests are used to predict how a soil in the field will deform in response to a change in effective stress.

Incremental Loading Test

The first loading frame that gained wide acceptance was used in the 1930s by Terzaghi and Casagrande (links). A more refined loading frame was developed by Casagrande at Harvard. An updated loading frame that is still used today was developed by Bishop at Imperial College, London.

Notes from Mesri's books

Taylor, Donald W. (1942). Research on Consolidation of Clays. Massachusetts Institute of Technology

Bjerrum, Laurits; Casagrande, Arthur; Peck, Ralph; Skempton, Alec. (1960). From Theory to Practice in Soil Mechanics. John Wiley & Sons, Inc.

(p44 theory to practice) "The first experimental work seems to have been that carried out by Frontard in 1910. A sample 2 in. thick and 14 in. in diameter was placed in a metal container with a perforated base and loaded through a piston; the test was made in a room at a very high humidity to prevent drying out of the clay. Each increment of pressure was left in position until equilibrium was attained, and the results were plotted as a graph relating water content and pressure." .. "in spite of the small thickness of the sample, five days was the minimum period for complete consolidation."

"This was the state of the subject when Terzaghi commenced his research in 1919 at Robert College, Istanbul. During the next six years he carried out a series of masterly experiments, both on consolidation and shear strength.." .. "In consolidation tests, starting with clay at the liquid limint, increments of pressure up to about 1 kg/sq. cm were applied in the odometer shown in Fig. 1(a). The apparatus was then dismantled and the 8cm diameter bronze ring with its contained clay was removed and set up in the manner shown in Fig. 1(b), under a pressure of 2 kg./sq. cm. After equilibrium had been attained, pressures up to about 20 kg/sq cm were applied, each increment remaining constant for two days to allow consolidation to be completed before the next load was added. The pressures were then progressively decreased to zero, when the clay (p45) was again loaded to a pressure rather greater than the first maximum. The data were expressed as a relationship between void ratio e and pressure p; the first set of curves were published in 1921."

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Consolidation experiments were first carried out in 1910 by Frontard. A thin sample (2in thick by 14in in diameter) was cut and placed in a metal container with a perforated base. This sample was then loaded through a piston incrementally, allowing equilibrium to be reached after each increment. To prevent drying of the clay, the test was done in a room with high humidity. (p44 theory to practice)

Terzaghi started his consolidation research in 1919 at Robert College in Istanbul. (p44 theory to practice) Through these experiments he started to develop his theory of consolidation (link) which was eventually published in 1923. During his time at M.I.T. (link) from 1925-29, Terzaghi's testing methods and apparatuses were improved. (p6-7 theory to practice)

Casagrande was at MIT from 1926-1932 and worked with Terzaghi on

Research at MIT was continued in the 1940s by Taylor. (taylor book)