Study on River Bed Material and Numerical Analysis of Stabilized Road Embankment on Soft Soil

Abstract

The experimental study has been carried out to evaluate the effectiveness of stabilization of the river Brahmaputra bed materials with varying percentages of Portland cement. Numerical modeling has been done to study the suitability of the stabilized river bed material with respect to strength and settlement. The Brahmaputra River Bed materials were stabilized with Portland cement with varying percentages (2, 4, and 6%) cured for 7, 14, 28, 45, and 90 days. The samples were cured in a humidity control chamber at temperature 30 ± 1 °C and humidity 95 ± 1%. The mechanical behavior of this potential new material was assessed by a series of tests, including unconsolidated undrained triaxial tests on samples with different percentages of cement. It is revealed from the results that the stabilized bed materials are suitable for use in subgrade of the embankment of the low volume roads as per relevant standards. To investigate the performance of an embankment constructed using the proposed material, a numerical analysis was undertaken using the software Plaxis with the properties obtained for an embankment fill material (i.e., cement stabilized and unstabilized soil). The highway embankment has been consisting of four layers, the bottom two layers represent natural soft subgrade and the top two layers represent the embankment fill with stabilized river bed materials. In the present paper filling material has been considered as an elasto-plastic material. Plastic behavior of the filling material has been defined by Mohr–Coulomb plasticity model and the input parameter for numerical analysis has been obtained from laboratory experiments.