Dynamic Analysis of Hunchback Concrete Block Quay Wall and Recommendation for Optimum Geometrical Parameters

Concrete block quay wall, is consisted of solid or hollow concrete blocks sitting on each other to form the wall section. In this type of wall geotechnical condition, design calculation and ability of contractor determine the blocks dimensions. In these walls resistance against applied loads is provided by wall weight. To reduce active soil pressure and to increase wall stability in seismic regions, hunchback section is formed by placing a protruding knapsack to landside. In this formation according to backward tendency of blocks, wall stability will be increased. For knapsack section, special considerations such as trimming the blocks, more accurate setting blocks and consequently increasing construction costs should be considered. “Inclination angle” and “ratio of inclination height to entire wall height” play an important role in geometrical design of hunchback section. Selecting proper amount of these two helps decreasing soil dynamic pressure behind the wall and consequently reduces the concrete volume required construction. In this article, in order to evaluate the proper amount of “inclination angle” and “ratio of inclination height to entire wall height”, applying numerical modeling, FLAC 2D is used for modeling different hunchback block quay walls. Comparing the results, the proper amounts of the aforementioned parameters have been recommended. The results of modeling are categorized in below sections. - Soil dynamic pressure behind the wall, - Displacement of upper block - Concrete volume required for construction of unit berth length. The results show that a negative inclination angle of 50-55 degree which starts from middle of the wall height is the optimum formation to reduce the soil pressure and the concrete volume per berth length unit.