Requirements for Annular Gap Mortar for TBM Driven Tunnels With Single Segmental Lining

The complete backfilling of the annular gap between the excavation contour and the outer contour of the segmental ring with a suitable material is an essential element for supporting the rock mass, for ensuring the load-bearing capacity of the segmental ring and thus also the stability of the tunnel, as well as for avoiding water flow in longitudinal direction along the tunnel. In this article, essential aspects of annular gap grouting are explained on the basis of exemplary projects. For the selection of the material as well as the method of backfilling, the various influencing factors such as subsoil, TBM, segment lining, construction aspects, durability of the material as well as any special conditions must be considered in a realistic manner. Three-dimensional stability and seepage flow analyses are suitable for this purpose, if they take into account the areas of the temporary face, the shield and the segmental ring as well as the surrounding rock mass. Due to the complexity as well as the importance of this issue, investigations and selection of a suitable annular gap filling material should already be carried out in the planning phase.

1 Introduction

In TBM driven tunnels, the segmental lining is installed inside the shield. With the aid of the jacks, the finalized segmental ring is pressed against the already installed rings and held in place via vertical frictional forces. In this state, driving continues, the segmental ring leaves the shield, and an annular gap in the order of one to three decimeters is created between the excavation contour and the outer contour of the segmental ring. This annular gap must be backfilled with a suitable material to ensure an adequate support of the rock mass, the load-bearing capacity of...

Related articles:

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 2020-04

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

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...

more
Issue 2019-05

Red Line Tel Aviv: Planning and Constructing the TBM Tunnels of the Eastern Section (Part 2)

6 Annular Gap Grout A cement-based mortar was used for grouting the annular gap for tunnelling the eastern section of the Tel Aviv Red Line [2]. The mixes applied are presented in Table 1. The grout...

more
Austrian Tunnel Day 2018

STUVA Research awarded Innovation Prize

Water-permeable Annular Gap Material for Single-Shell Drained Segment Linings

On 10 October 2018, the Austrian national committee of the International Tunnelling and Underground Space Association (ITA) awarded their innovation prize to the STUVA for the “development of a...

more
Issue 2014-06 Bolting Technology

Mineral Dry Mortar

Sika Deutschland GmbH offers SikaRock Anchor Mortar 1 and SikaRock Anchor Mortar HS – two hydraulically hardened and pure mineral dry mortars – for anchoring rock nails and filling anchor drill...

more