Behaviour of Cohesive Soil-Flyash Layered Matrix Under Cyclic Loading

Abstract

The present study investigates the effect of cyclic loading conditions on the performance of soil-flyash layered matrix under different intensities of failure load (I = 25, 50 and 75%) with varying number of cycles (N = 100, 200 and 300). The number of cycles, confining pressures and the intensity of failure loads were varied using triaxial compression testing machine on layered soil-flyash samples. It is observed from the study that nature of stress–strain relationship is initially linear for low stress levels and then turns nonlinear for high stress levels. The experimental results show that the effect of confining pressures of 50, 100 and 150 kPa on deviator stress at failure is significant at higher intensity, I, of the load at which loading–unloading is performed for cohesive soil-flyash layered matrix. The study shows that the deviator stress at failure and cohesion continuously increases with increase in the number of cycles N at lower values of intensity of load, I (I = 25%) in soil-flyash matrix under cyclic loading conditions which signifies good performance of this combination under lower percentages of failure stress levels. The experimental investigation demonstrates the use of flyash in layered combination with cohesive soils under lower number of cycles with high intensity of load I, and for higher number of cycles with lower value of intensity of load I.