Deterministic Cost Optimization of Soil Nailing Walls for Highway Applications

Resumo

In the modern days, retaining structures are becoming even more important, especially in the context of infrastructure development. They are used to retain slopes and can be applied in highways, railways, building’s underground levels, among others. Therefore, in order to solve the need for a retaining wall in a real highway section, the solution chosen to be constructed is the soil nailing. Moreover, to evaluate the stability of this type of structure, it is often used the S Factor of Safety (FoS). This factor is used to measure the structure’s load-bearing capacity over the stress it will be subjected to. However, as it is common in geotechnics to have numerous agents involved in the bearing capabilities of a structure, it is common practice to use a single Global Safety Factor, which considers different variables and their interrelationships. On this topic, many software programs can be used to help determine the global safety factor by analyzing a structure’s stability. In the present study, the software Plaxis 2D will be utilized, which uses the Finite Element Method (FEM) to analyze the numerous variables of a geotechnical project and help determine the FoS. When viewing this context, one might think that adopting a greater safety factor will result in a safer structure, however, an oversized structure equals a greater cost of construction for the contractor. Thus, to help the construction of safe and cheap structures, it is crucial to optimize its design.But this process consumes a great amount of time, when done manually, and because of that, in this work the Deterministic Design Optimization (DDO) method will be applied. This method consists in using a coding language to interact with Plaxis, which is able to modify the wall’s parameters and help to determine the optimal design. For example, the coding language that will be used in this project is Python, in Pycharm, an Integrated Development Environment (IDE).Hence, the main objective of this project is to optimize a soil nailing wall of a highway section using deterministic methods. By doing this, parameters of cost will also be implemented in order to find a design that will meet the safety requirements, but one in which its cost of construction will also be minimum, resulting in a safe and relatively cheap soil nailing wall.