Development of a High Early-Strength Anchor Mortar for Tunnel Construction

This article describes the development of a high early strength anchor mortar that is to be used in tunnel construction to secure the outer lining of the tunnel. Anchor mortars currently available on the market have a curing time of one to several days, while the anchor may not yet be loaded. Accelerating the curing process could significantly speed up the load-bearing capacity and improve the utilisation of the anchors. In this context, the early creation of a load bearing vault plays an important role, as it would allow to reduce the thickness of the outer lining. The construction progress could be accelerated by an anchor mortar with high early strength, thus contributing to cost savings.

1 Introduction

In tunnel construction, a reduced construction time leads to significant cost savings. Therefore, the demand for faster construction processes is high. Any curing time that exceeds the required working time is an economic and technical disadvantage. Also, due to construction constraints, anchoring may be scheduled for specific time windows (e.g. night shift). This procedure requires a high early-strength anchor mortar. Furthermore, in areas where it is necessary to ensure the full load-bearing capacity of the anchor within a short period of time (e.g. fault zones), so far...

Related articles:

Issue 06/2014 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...

Issue 03/2018

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...

Issue 03/2013 Anchoring

„Semmering Base Tunnel New” – Securing the Precut with ­Self‑Drilling Anchors

In April 2012, work started on one of the most ambitious construction projects of Austria’s ÖBB-Infrastruktur AG: the New Semmering Base Tunnel. Scheduled for completion in 2024, the 27.3 km long...

Issue 05/2015 Hagerbach Test Gallery

Shotcrete: Early Strength and Strength Development

Shotcrete has developed from an auxiliary building agent to an efficient construction material. This is due to intensive development of the starting materials and processing equipment as well training...

Issue 02/2023

Test Methods for the Acquisition of Additional Material Properties of Two-Component Mortars

The tunnel boring technique poses significant demands on the stability of the tunnel tube, which depends on various factors including the time-dependent strength and stiffness development of the...