Behavior of cantilever and counterfort retaining walls subjected to lateral earth pressure K. Senthil*, M. A. Iqbal and Amit Kumar Three-dimensional (3D) finite element simulations have been performed in order to study the response of cantilever and counterfort retaining walls subjected to lateral earth pressure using ABAQUS/Standard. Four retaining walls with different geometrical configurations were analyzed including three cantilever and one counterfort wall. The results thus obtained were compared, and the mechanics involved in the behavior of the retaining wall was discussed. The lateral displacement, vertical settlement, and stresses developed in each component of the retaining wall were studied and compared with the other walls. The choice of the retaining wall based on the economic analysis was also discussed and compared. Keywords: Retaining wall, Reduced height counterfort, Lateral earth pressure, Economic analysis Introduction The retaining walls are generally used to retain, either earth or water in a vertical position at locations where an abrupt change in ground level either exists or arises because of transportation facilities, underground struc- tures, and storage tanks. In general, the failure of the retaining walls occurs because of sliding, overturning, and loss of bearing capacity. There are some important factors responsible for the failure of retaining walls such as excessive earth pressure, reduced resistance against sliding, and unbalanced inertial force. As such there is no methodology to identify the progressive effect of these factors on the retaining wall. However, the finite element technique has emerged as an important tool to predict such problems. Clough and Duncan (1971) computed the response of 6?0-m high gravity retaining wall placed on 6?0-m deep sand foundation experimented earlier by Terzaghi (1934). The analysis was performed using one-dimensional elements to simulate the interface between the wall and the backfill. The minimum active and maximum passive pressures were found to be in good agreement with the results of the classical earth pressure theory, whereas the amount of movement required to reach the full active and full passive conditions was found to be in good agreement with the results of Terzaghi (1934). Matsuo et al. (1978) conducted experiments on 10-m high concrete wall retaining the silty sand and slag. The earth pressure on the wall was continuously measured up to 4 months. The measured static earth pressure was compared with the results of finite element analysis. The computed results were found to be insensitive to density and young’s modulus, however were very sensitive to the Poisson’s ratio. Bhatia and Bakeer (1989) reproduced numerically the experimental results of Matsuo et al. (1978) and found that the predicted earth pressure is significantly affected by the size of the element as well as the boundary conditions employed. Green et al. (2008) and Green and Ebeling (2003) con- ducted two-dimensional (2D) non-linear explicit dynamic analysis to determine the response of 6?1-m high cantilever concrete wall against earthquake motion. At very low accelerations, the induced pressures obtained by fast Lagrangian analysis of continua (FLAC) were found to be in agreement with those predicted by the Mononobe– Okabe approach. However, as the accelerations increased to those expected in the region, the induced pressures were found to be larger. The reason for the same was attributed to the relative flexibility of the structural block and non- monolithic motion of the driving soil wedge. The perma- nent relative displacement of the wall was in accord with those predicted using the Newmark sliding block approach. Chugh (2005) conducted finite element analysis for a model of cantilever wall and prototype counterfort wall using FLAC 2D and 3D. The discretization of the wall into finite-difference grid affected the natural frequency of free vibrations; the grid size effects were more pronounced for vibratory response in the transverse direction than in the axial direction. The numerical results of natural frequency were found to be in agreement with those of the known analytical solutions. Liu et al. (2006) conducted two-dimensional finite element analysis on 5-m high reinforced concrete wall in order to obtain the relationship between displacement and Department of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India *Corresponding author, email urssenthil85@yahoo.co.in; abuovdce@iitr.ernet.in ß 2014 W. S. Maney & Son Ltd Received 13 April 2013; accepted 21 June 2013 DOI 10.1179/1938636213Z.00000000075 International Journal of Geotechnical Engineering 2014 VOL 8 NO 2 167