Optimization of Inclined Base Cantilever Retaining Walls with The Harmony Search Algorithm

Cantilever retaining walls have been commonly utilized to ensure stability of two different soil levels in geotechnical engineering. In design of cantilever retaining wall, there have been many soil parameters and wall dimensions affecting stability of retaining wall like angle of internal friction, cohesion, wall height, length of base, thickness of base and so on. By using traditional methods, making safety and economic cantilever retaining wall design as soon as possible is time-consuming and trying. Because of these reasons, some effective and easy to apply optimization methods have come into prominence in this kind of design. In this study, optimization of inclined base cantilever retaining wall which is one of the cantilever retaining wall has been investigated with the harmony search algorithm. In the optimum design of the wall, statistically derived mathematical formulas with reasonable absolute relative error have been employed. Safety factors of sliding, overturning and slope stability of the wall have been determined by using these mathematical formulas. These formulas of safety factors are taken as objective function and constraints in process of optimum design. To obtain safety and economic wall design, values of lower and upper limit have been selected for constraints. The length of base, the toe extension, the thickness of base, the slope of base and the angle of internal friction have been taken as design variables with four levels. National and international pre-design guidelines have been used in determination of the lower and upper limits of design variables. For mathematical formulas of all safety factors, 16 inclined base cantilever retaining wall design have been performed by using Taguchi L16 design table which is revised according to five parameters with four level each of them. Obtained results show that harmony search algorithm and mathematical formulas can be used effectively in optimum design of inclined base retaining wall.