The mechanical characteristics of Yellow River crossing tunnel composite linings in the south-north water diversion project

摘要

In the middle of the South-North Water Diversion Project lies the Yellow River Crossing Tunnel Project, which is a long-distance, deep-buried, pressured water-conveyance tunnel that crosses the river bed of the Yellow River. This project is the key controlling project of the middle route scheme. The project contains a bilayer composite lining structure: the external lining is reinforced concrete, and the internal lining is a 45 cm-thick anchor ring prestressed concrete. This structure has thin concrete lining thickness, high ring anchor curvature, and high tensile stress. In this study, the composite lining structure of the Yellow River crossing tunnel was evaluated using the 3D finite element method to examine the mechanical characteristics of this new structure type. The analysis examines the construction period, the water-filling operation period, and the complete water head operation period to evaluate the deformation and force transfer mechanism of the external lining segment and the prestressed internal lining ring anchor. The results showed that the bilayer composite lining possessed individual load-carrying characteristics. The tunnel exhibited excellent deformation under internal and external water pressure. The study also found that this approach satisfied safety standards.