Effect of Pore Water Pressure on Stress- Strain Characteristics of Dense Sand

This study evaluates the effect of pore water pressure on the strength characteristics of uniform white dense sand using consolidated drained triaxial test. The stress-strain behavior of the samples was measured at different confining pressures. A series of tests were performed at different values of pore water pressure in the range of 0 to 100 kPa with an increment of 25 kPa under different confining stresses. The pore water pressure is applied before starting the test and kept constant during the test for the purpose of comparing the results at the same effective confining pressure. At the same confining pressure, the results show that the maximum deviator stress decreases as the pore water pressure increases. A single linear relationship was developed for showing the variation of the maximum deviator stress with the increase of the effective confining pressure. However, such a relationship depends on the pore water pressure value for the condition of total confining pressure. Where a reduction in the total angle of friction was noticed as the pore water pressure increases, insignificant change in the values of effective angle of friction was noticed. A linear relationship was developed showing the variation of the modulus of elasticity with the effective confining pressure.