Computation of passive earth pressure coefficients for a vertical retaining wall with inclined cohesionless backfill

Abstract

Background: Understanding the behaviour of retaining walls subjected to earth pressures is an interesting but a complex phenomenon. Though a vast amount of literature is available in this study area, a majority of the literature, either theoretical or experimental, address the problem of a vertical retaining wall with a horizontal backfill. Therefore, it is decided to develop a limit equilibrium based protocol for the evaluation of passive earth pressure coefficients, K pγ for a vertical retaining wall resting against the inclined cohesionless backfill. Methods: The complete log spiral failure mechanism is considered in the proposed analysis. Though the limit equilibrium method is employed in the present investigation, an attempt is made to minimise the number of assumptions involved in the analysis. Results: The passive earth pressure coefficients are evaluated and presented for the different combinations of soil frictional angle ϕ, wall frictional angle δ and sloping backfill angle i. The solutions obtained from the proposed research work are very close to the best upper bound solutions given in the literature by Soubra and Macuh (P I CIVIL ENG-GEOTEC 155:119-131, 2002) for the K pγ coefficients. A comparison of the proposed K pγ values is also made with the other available theoretical as well as experimental results and presented herein. Conclusion: As the method developed herein is capable of yielding the best possible upper bound solution and being simple to implement, it could be considered as one of the alternatives for the evaluation of passive earth pressure coefficients for a vertical retaining wall resting against the inclined cohesionless backfill.