Abstract

The traditional method of installing underground utilities, which is based on burying them under the roads, has been used for many decades. Repeated excavations related to this method cause many problems, which can significantly increase the actual costs as well as social costs. Multi-purpose Utility Tunnels (MUT) are a good alternative for buried utilities. Although MUTs are more expensive than the traditional method, social cost savings can make them more practical. Different factors should be investigated to determine if MUTs can be an economical and practical alternative. The construction method is one of the most important factors that should be carefully assessed to have a successful MUT project and reduce its impact on the surrounding area. Simulation can be used for investigating the different construction methods of MUTs. In this research, two stochastic discrete event simulation models depicting two MUT construction methods (i.e., microtunneling and cut-and-cover) are developed. The purpose of these models is to analyze the duration and cost of the MUT projects. Also, 4D simulation models of these methods are developed for constructability assessment of these projects. The conclusions of this research are as follows: (1) the duration of C&C method is more sensitive than microtunneling to the changes in tunnel diameter; (2) the cost of microtunneling method is more sensitive than C&C to changes in tunnel diameter; (3) in average, microtunneling is 52% more expensive and 66% faster than C&C; (4) the impact of the microtunneling on the surrounding area is less than the C&C.