Optimization of weight type mortar rubble stone retaining walls under the influence of static loads

In this study; an optimization problem was developed to find the optimum cross-sections of grouted rubble masonry gravity walls of 3-10 m height, under the influence of active earth pressure and this problem was solved with a program written in the MATLAB compiler. The study was started with the determination of the design variables that define the cross-section geometry of masonry gravity walls manufactured in the market and used by public institutions. The wall cross-section area was chosen as the objective function and the design variables were selected as the outline lengths of the cross-section. Constraint functions were derived from external stability verifications (overturning, sliding and bearing capacity),constructive and mathematical rules. Internal friction angles of soil were selected as 20°, 30° and 40° to examine the effect of different soil types on the optimum cross-section; and the active earth thrusts were determined by Coulomb Theory. The effects of height and internal friction angle on the optimum section were investigated by keeping constant the other soil and wall, and the values of the design variables, objective function and constraints were found using the 'active-set' algorithm. Thus, optimum wall cross-sections were determined and optimum cross-section areas were calculated. For the same wall height and soil properties, the commonly used classical cross-section was compared with the optimum cross-section obtained in this study, and it was seen that the area of the optimum cross-section was lower than the area of the classical cross-section. As a result, minimization of the objective function was achieved and it was determined that more economical walls could be manufactured.