The selection of the optimum trenchless pipe laying technology with the use of fuzzy logic

Abstract

Presently, several trenchless pipe laying technologies are used. Those are applied under different conditions and show different, specific values of technical parameters. With a great variety of technologies available, key challenges are the selection of appropriate technology for a given project and the choice of the criteria that should be taken into consideration. The use of inappropriate technology can cause major problems in the maintenance of laid pipelines, or can even result in the failure of pipe laying. For that reason, the mathematical model which allows the choice of the optimal trenchless pipe laying technology was developed. In the model, fuzzy logic was used. Assumptions and input quantities were determined and presented. Limiting conditions in the form of linguistic variables were given. Those include the following: the possibility of pipe laying in a given soil type using a given trenchless technology; the possibility of laying the pipeline of a given diameter using a given trenchless technology; the lengths of pipelines laid in one drive, characteristic of each technology; the possibility of laying the pipeline of a given material for a given technology and the deviation of an installed pipeline slope from the designed slope, characteristic of each technology. For those variables, linguistic term-sets and universes of discourse were determined and presented. Membership functions, grades of membership attributed to them, and also fuzzy sets qualified for particular linguistic variables were introduced. The algorithm of the mathematical model was constructed. Finally, the verification of the model for real trenchless pipe laying projects, was presented.