Shaft Design for the Rijnlandroute Bored Tunnel

Abstract

This article elucidates how the launching and arrival shafts of the Rijnlandroute bored tunnel, near Leiden in the Netherlands, are designed and executed. Special attention is given to the behavior of the diaphragm walls during excavation of the shaft and when the tunnel boring machine enters the surrounding soil mass. The global stability of the shafts, subjected to high asymmetric horizontal loads, and an execution methodology ensuring watertight mining through the diaphragm walls are the main points of interest. The adoption of a permanent bell as an alternative to the more commonly used starting plug will be described, as well as the design details of the “soft eye” to ensure a good concreting process of these diaphragm walls.

Keywords:

• GFRP reinforcement
• launching shaft
• arrival shaft
• diaphragm wall
• global stability

Disclosure statement

No potential conflict of interest was reported by the authors.