BEHAVIOUR OF REINFORCED EARTH EMBANKMENTS

Abstract

The technique of using reinforcement layers in the construction of embankments is finding a wide use, where land space is restricted and steeper slopes are required. A design approach for assessing the stability of reinforced embankments by limit equilibrium method is presented. Adopting the circular wedge failure mechanism using Swedish Circle method assesses the stability. The integrals involved in Swedish Circle method have been evaluated analytically and the failure wedge is considered as single body mechanism. The charts given by Jewell (1990) did not discuss the design of embankment considering the surcharge load and Cohesive - frictional soil. Hence a need was 'felt to provide solution for the case when the embankment is of cohesive-frictional soil and acted upon by surcharge. - The -focus of attention for steep embankments has been the distribution of maximum required stress in the slope and the provision of reinforcement with a sufficient length so that the stress generated from the reinforcement layers exceeds the maximum required stress at every depth to keep the embankment stable. The design described in the present work is the stability analysis, orstrength limit state, which seeks to ensure an adequate margin of safety against collapse. The major objective of the thesis is to see whether reinforced slopes might be designed with less reinforcement material, but to the same level of safety. The increase in slope as well as the increase in load that can be provided after reinforcing the embankment for a factor of safety of 1.3 to attain a factor of safety of minimum 1.0 has been obtained from the stability charts.