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Stress-strain behavior and liquefaction strength characteristics of Ottawa F65 sand
Abstract The stress-strain-strength response of soils is of significant interest to development and calibration of realistic constitutive models that can be used in numerical simulation of geotechnical engineering problems. An extensive characterization of Ottawa F65 sand along with various monotonic and cyclic tests conducted during the course of the Liquefaction Experiments and Analysis Projects (LEAP) are presented here. The specimens in these tests were prepared using a meticulous sample preparation technique to facilitate their consistency and repeatability. Monotonic drained and undrained triaxial tests shed light on the steady-state (critical state) of Ottawa sand, while stress-controlled and strain-controlled cyclic triaxial and direct simple shear tests provide key information on the cyclic stress-strain behavior and liquefaction strength of this soil. The triaxial tests identify the liquefaction strength of the soil at different densities, while the direct simple shear tests evaluate the effect of overburden pressure on the cyclic response. The results of these experiments are also compared to the experimental results available in the literature. The data obtained from the cyclic triaxial and direct simple shear tests were further analyzed by plotting the computed shear modulus degradation and damping curves. The results show how the soil stiffness degrades as cyclic shear stress is applied for soil at different densities and confining stresses. It can be seen that the rate of shear modulus degradation increases with the increase of confining stress and decreases with the increase of soil density. The damping curves consistently show an increasing in damping ratio until a shear strain of about 0.05%, followed by a plateau at about 20–25% damping ratio for shear strain between 0.05 and 0.5%, and ending with a decrease in damping until reaching a final damping ratio of about 10%.
Highlights An experimental study was presented on the stress-strain response and liquefaction strength of Ottawa F65 sand. 23 stress-controlled cyclic triaxial tests were performed on samples of different relative densities (71.5, 87.5 and 97.5%). 37 strain-controlled cyclic triaxial tests were performed on samples of different relative densities (40, 63.8 and 75.6%). 11 cyclic direct shear tests were conducted on samples under 100 and 40 kPa overburden stress. Results showed consistency and repeatability, and shear modulus degradation and damping curves were computed for each test.
Stress-strain behavior and liquefaction strength characteristics of Ottawa F65 sand
Abstract The stress-strain-strength response of soils is of significant interest to development and calibration of realistic constitutive models that can be used in numerical simulation of geotechnical engineering problems. An extensive characterization of Ottawa F65 sand along with various monotonic and cyclic tests conducted during the course of the Liquefaction Experiments and Analysis Projects (LEAP) are presented here. The specimens in these tests were prepared using a meticulous sample preparation technique to facilitate their consistency and repeatability. Monotonic drained and undrained triaxial tests shed light on the steady-state (critical state) of Ottawa sand, while stress-controlled and strain-controlled cyclic triaxial and direct simple shear tests provide key information on the cyclic stress-strain behavior and liquefaction strength of this soil. The triaxial tests identify the liquefaction strength of the soil at different densities, while the direct simple shear tests evaluate the effect of overburden pressure on the cyclic response. The results of these experiments are also compared to the experimental results available in the literature. The data obtained from the cyclic triaxial and direct simple shear tests were further analyzed by plotting the computed shear modulus degradation and damping curves. The results show how the soil stiffness degrades as cyclic shear stress is applied for soil at different densities and confining stresses. It can be seen that the rate of shear modulus degradation increases with the increase of confining stress and decreases with the increase of soil density. The damping curves consistently show an increasing in damping ratio until a shear strain of about 0.05%, followed by a plateau at about 20–25% damping ratio for shear strain between 0.05 and 0.5%, and ending with a decrease in damping until reaching a final damping ratio of about 10%.
Highlights An experimental study was presented on the stress-strain response and liquefaction strength of Ottawa F65 sand. 23 stress-controlled cyclic triaxial tests were performed on samples of different relative densities (71.5, 87.5 and 97.5%). 37 strain-controlled cyclic triaxial tests were performed on samples of different relative densities (40, 63.8 and 75.6%). 11 cyclic direct shear tests were conducted on samples under 100 and 40 kPa overburden stress. Results showed consistency and repeatability, and shear modulus degradation and damping curves were computed for each test.
Stress-strain behavior and liquefaction strength characteristics of Ottawa F65 sand
ElGhoraiby, Mohamed A. (author) / Park, Hanna (author) / Manzari, Majid T. (author)
2020-06-22
Article (Journal)
Electronic Resource
English
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