Cover Story

Combined Cement-Polyurethane Grouting Operations in Tunnel and Shaft Construction

Cement-based or chemical grouting materials are the foremost choice to seal water-bearing areas in subsoil or rock efficiently. Anti-wash out resistant cement-based grout mixes and water-reactive grouting materials based on polyurethane are the preferred material for pre-excavation grouting. However, adequate equipment and material technology nowadays enable controlled processing of combined cement-polyurethane grout mixes, which withholds the benefits of both materials types.

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Forschung & Entwicklung | Research & Development tunnel Series: Interaction Modeling in Mechanized Tunnelling, Part 4

Deformation-Tolerant Tunnel Linings in Swelling Soils

Mechanized tunneling in difficult geological conditions, such as soils with significant swelling potential due to water uptake by the clay minerals, depends not only on the calibration of the tunnel boring machine to the ground characteristics, but also on the ability of the tunnel lining to tolerate localized swelling pressures. In order to avoid the risk of damage to the tunnel lining, additional radial layers such as a compressible tunnel lining segment and a compressible annular gap grout can be included. However, the deformability of a tunnel support after reaching a certain yielding load affects the distribution of the stresses and deformations around the tunnel and as a consequence determines the magnitude and buildup of the swelling pressure. Thus, the goal is to develop a lining system i.e. material design and structural design that ensures an optimal soil-structure interaction through a synergy of computational and experimental techniques.

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TUNNEL - Ressort

Design and Construction of Tunnels in Jointed Rock According to the AJRM Method – Part 2

The first part of this article was published in the 3/2021 issue of tunnel [15]. There, the authors present the AJRM method. The rock mechanical model is explained. With the aid of case studies, the advantages of a realistic simulation of the behavior of jointed rock as well as of the interaction of rock mass and structure are illustrated. As announced, part 2 of the article deals with the rock hydraulic model and related case studies as well as with the determination of the required parameters. Thus, an overall method for a safe and economic design of structures as well as for groundwater modeling in jointed rock is available.

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Nachrichten | News Austria

14–16 October 2021: 70th Geomechanics Colloquium in Salzburg

The annual geomechanics colloquium has developed as an important meeting point for experts in Central Europe. The event with the associated exhibition annually attracts over 800 participants, making it one of the largest events in the field of geomechanics worldwide. Due to the pandemic, the 69th Geomechanics Colloquium in 2020 was held in a virtual format. The board of the Austrian Society for Geomechanics has decided to hold the colloquium again this year at the Salzburg Congress Centre as a physical event

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Nachrichten | News Italy

Advance Record at the Brenner Base Tunnel

The miners in the Brenner Base Tunnel are pushing ahead rapidly with the major rail project. On March 31, 2021, they achieved a new record while excavating the main tubes in South Tyrol: 860 m of tunnel bored and lined in one month.

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STUVA-Nachrichten | STUVA News

STUVA Conference 2021 Planned as a Face-to-Face Event

The decision has been made: Thanks to the far advanced vaccination campaign against the coronavirus, the „family reunion of the tunnel industry“, the STUVA conference with accompanying trade exhibition STUVA-Expo, is to take place as a face-to-face event in the familiar manner from 24 to 26 November 2021 at Messe Karlsruhe.

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Digitale Bauprozesse | Digital Construction Processes Eguana

Management and Analysis of the Surge of Digital Data for Injection Measures

If one considers an injection campaign for sealing fault zones in tunnelling with regard to the quantity of data obtained, one has to reckon with up to 500 injection points daily, or with, for example, three injection passes per metre and not infrequently 50 advance injection boreholes per round. Assuming a drilling depth of only 20 m, this already results in 3000 injections. For drilling and injection, equipment is used that records numerous measured values and parameters, such as different pressures and flow rates as well as rotation speed. Calculated briefly, this means that for an average 30-minute injection alone, more than 5000 measured values are recorded and processed. That adds up to an incredible 1 000 000 readings for a comparatively conservative 200 injections. Every day. And this flood of data only concerns the logged series of readings from the injection operations. In addition, drilling data or, for example, construction process data, signs of wear and reactions of the rock also contribute to the accumulation of data.

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Nachrichten | News Denmark/Germany

Green Energy for the Fehmarnbelt Tunnel

A new transformer station for the Fehmarnbelt Tunnel has been put out for tender. Electric trains through the Fehmarnbelt Tunnel between Denmark and Germany will run on green energy supplied directly from a new transformer station. The contract for the new plant has just been put out for tender. The transformer station will also have sufficient capacity for a largescale charging station for electric vehicles near the tunnel.

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