Comparative Study of Backfill Retaining Systems for Onshore RCC Pile Berth Under Different Site Conditions

Abstract

The study is focused on analyzing and designing backfill retaining systems for a berth with respect to permissible deflection and overall consumption of concrete and steel. It includes analyzing and designing of RCC piled jetty with three types of earth retaining systems, namely slope fill (Type 1), diaphragm wall separate from the jetty (Type 2), cantilever wall attached to the jetty (Type 3), and with two different vessels of 5000 DWT (V₁) and 3000 DWT (V₂) under different site conditions. The different conditions consist of different water depth, different soil conditions (loose, medium, and hard), different seismic zone (II, III, IV, and V), and earth pressure for different backfill soil parameters and slope fill. The Axial force, Moments (M_y and M_z), and Concrete and Steel consumption are compared with respect to different water depths for all the zones and type of soils. The three systems are then compared against one another to find the most economical section. Also, the material consumption factor is found. It was observed that the slope fill (Type 1) and 9 m system are most suitable in terms of economy as a backfill retaining system for onshore RCC pile berth. With the change in soil from hard to loose, the pile diameter increases. Also as the width of jetty increases, in case of Type 1 system, the structure becomes less economical due to increased forces.