Test Methods for Simulating the Solidification Process of Annular Gap Backfilling Materials

If a tunnel is driven by a TBM, the so-called annular gap remains between the ground and the tunnel lining, which must be filled during the tunnel drive. The essential process for the grouting procedure differs according to the annular gap backfilling material used, depending on the given (hydro-)geological and project-specific boundary conditions. In the case of one-component grouts a dewatering of the grout takes place into the surrounding soil corresponding to its permeability during the pressure-related grouting process. This leads to a consolidation of the grout. In non-permeable or insufficiently permeable soils a solidification process through interaction with the surrounding soil is not possible. In such cases, two-component grouts are used that harden through a chemical reaction between the activator and the cement. In this publication, methods for simulating the solidification process of different annular gap backfilling materials are presented.

1 Introduction
1.1 Necessity of the Annular Gap Backfilling

In mechanized tunnelling a gap remains between the segmental lining and the excavated ground – the annular gap – that must be completely filled with a suitable annular gap backfilling material immediately after installation of the segments. The annular gap backfilling serves for the immediate positive- and force-locking bedding of the installed segment ring. This prevents the tunnel lining from floating as well as from sinking under the load of the TBM’s backup. In addition, the primary stress state of the soil can be largely...

Related articles:

Issue 2019-04 MC-Bauchemie/Porr Bau GmbH

New Cementless TBM Backfill Grout

In mechanised tunneling, concrete segments can be positioned to create the inner lining of the tunnel. The action of the tunnel boring machine is toleranced to create a clearance between the...

more
Issue 2019-05

Rehabilitation of a Deteriorated Metro Line with Injection Technology

1 Compartment Barriers and Curtain Injections 1.1 Resins and Equipment ? Foam Seal is a dual component, quick reacting, slightly flexible silicate-based injection foam. It is used mostly for safe...

more
Issue 2016-07 Research and Development

New Test Stand for annular Gap Mortars

A qualitatively high-grade tunnel lining requires the tunnel segment annular gaps to be properly grouted. At the same time, this provides a decisive contribution to a high rate of advance during...

more
Issue 2018-03

Strength Development of Two-Component Grouts for Annular Gap Grouting

1 Introduction and Motivation In mechanized tunnelling with segmental lining a cavity emerges during the production of the tunnel between the surrounding soil and the exterior wall of the tunnel with...

more
Issue 2018-03

New Joint Sealing Process for Segment Tunnels

Targeted Sealing of Leaks in Segment Linings In targeted sealing of leaks, the direct route through the joints between segment linings is used in order to drill through the gasket and inject grout on...

more