Prediction of the Stress-Strain Curve of Sand Under the Effect of Pore Water Pressure


Awad Ali Al-Karni

Associate Professor, Department of Civil Eng
College of Engineering, King Saud University
Riyadh, Saudi Arabia


This paper presents a study on the prediction of the stress-strain curve for sandy soil under the effect of excess pore water pressure using hyperbolic mathematical model. Since the model was calibrated and verified in previous study at zero pore water pressure, a testing program was conducted in this study to evaluate the characteristics of the stress-strain curve under the effect of excess pore water pressure which include the initial slope of the stress-strain curve, the final slope, the reference stress, the peak deviator stress, and the vertical strain at peak deviator stress. These characteristics are parameters that are needed to run the model and will be determined as a function of the confining pressure, the pore water pressure, and the relative density using the best fitting curve technique. The testing program includes drained triaxial tests that were carried out at different levels of confining pressure using saturated samples. Each of these tests was repeated at different levels of applied back pore water pressure where the initial applied back pore water pressure was kept constant during the tests to keep the effective confining pressure constant during the tests. The model prediction were compared with the experimental results and showed good agreements for all levels of applied confining pressure and pore water pressure.

Keywords: modeling, stress, strain, pore water, sand, triaxial.

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