Selecting efficient support methods for tunnels

TL;DR: In this paper, the authors present a model that helps decision maker in selecting tunnel support methods in the conceptual phase of the project and calculates efficiency percentages of support methods based on project conditions.

Abstract: Construction of a tunnel consists of many activities during the construction phase of the project, supporting is one of these activities. Immediate support elements are provided to control ground movement caused by stress redistribution during tunnel drive. Certain support elements are assembled in the excavated areas of crown, side wall and additionally on the tunnel face if necessary. Typical support elements are rock bolts, reinforced sprayed concrete, girders, etc. Loose ground and weak rock within the following rounds can also be supported using methods such as pipe umbrella, forepoling, earth wedge, etc. The Selection of efficient support methods for tunnelling is very important to reduce problems during construction and maintain project cost and time within the project budget and the planned schedule. This paper introduces a model that helps decision maker in selecting tunnel support methods in the conceptual phase of the project. The model calculates efficiency percentages of support methods based on project conditions. The model provides the user with a report including support methods and their efficiency percentages ranked in descending order.