CONTACT ELEMENT ANALYSIS OF A BARRAGE RAFT FOUNDATION

Abstract

The importance of barrages as an attractive alternative to large river valley projects is being more and more appreciated at the present stage in time. Ecological concerns, apart from others, have been a major reason for the social acceptance of large projects. However, attractive as it may seem, there has been an unintended apathy towards the smaller hydraulic structures from a research viewpoint resulting in an acute shortage of literature on which to base effective design rationales. An effort has been made in this dissertation to examine the effect of employing "contact" analysis to improve the FEM representation of the barrage raft for more realistic assessment of response to loads to which it may be subjected. The results of an experimental test on a typical barrage raft were used as benchmarks to evaluate the performance of three models i.e based on solid elements and two different plate models. The foundation media was considered as homogenous and non-homogenous and the contact was simulated using three coefficients of friction i.e. 0.1, 0.3 and 0.5. The results of analysis conducted indicate that contact does modify the response of the raft but the models considered and the parametric variation adopted lacked the inherent flexibility in the raft-foundation media of the experimental setup. The modeling of contact in a typical barrage structure between the components of the foundation media ie. Soil and rock interface also indicated that contact influences the response though to a limited extent, for the configuration adopted.