Performance-based design of joint waterproofing of segmental tunnel linings using hybrid computational/experimental procedures

摘要

Precast segmental linings of underwater tunnels, excavated by tunnel boring machine (TBM), are key components of infrastructure that is inevitably subjected to a relatively high-water table head. Many underwater tunnels experience various degrees of water leakage issues at the tunnel joints. A rigorous joint waterproofing design is indispensable to guarantee the normal operation of tunnels. However, to date, little attention has been devoted to gaining a better understanding of the water leakage behavior of joints and the associated design method. In this paper, a combined experimental- and computational-based design framework for joint waterproofing is presented, in compliance with the most recent guidelines. The proposed step-by-step design procedures incorporate the identification of design parameters and criteria, pre-test finite element (FE) analysis, experimental evaluation, and post-test FE analysis. The gasket assembly ability refers to the shear capacity check of the gasket groove during the construction stage, while the joint waterproof capacity consists of both the short-and long-term waterproof capacities of the joints in the most unfavorable deformation state during the service stage. A pre-test analysis is performed to evaluate the preliminary gasket profiles and is followed by experimental testing of the short-term waterproofing performance of the joint. A post-test FE analysis is performed to check the groove shear capacity and to predict the long-term waterproofing performance of the joint. A design case study of a recently built underwater tunnel in China is presented to illustrate the implementation of the proposed design procedures into practice. Finally, recommendations on the contribution of the governing variables on the waterproofing performance of the joint are provided, outlining crucial aspects that may be considered by engineers in the design of underwater tunnels.