Tunnel Waterproofing: Available Technologies and Evaluation Through Risk Analysis

摘要

The interaction of underground structures with groundwater is an essential issue for all the phases of the construction and life of an underground work. This issue is essential for its potential effects on the environment, on the excavation technique and on the preservation of the hydraulic resource. A complete analysis of all the problems related to this interaction from the very beginning of the design is of crucial importance for the good execution of the construction and for the minimization of the maintenance cost during the life of the structure. A wrong waterproofing approach or an incorrect installation of the waterproofing system may lead to severe damage to the structure, and to high maintenance and refurbishment costs. In the technical literature, water inflow in tunnels has been recognized as one of the most important sources both of damage to the structures and of claims. Several case histories have highlighted the importance of water preservation and the potential danger of underground excavation for the environment if insufficient controls of underground water are applied. In the paper, a global overview of the techniques used is presented, some relevant case histories are discussed, and a risk analysis procedure is proposed.