Solution methods for the design and construction of contract KAT3 of the Koralm Tunnel /

Abstract

The very variable geological conditions require two completely independent machine concepts for contract KAT3 of the Koralm Tunnel, which have been taken into account with the planned use of a shield machine capable of being rebuilt. This article discusses the essential constructional requirements for machinery and construction methods based on the current state of design and knowledge. Koralm Tunnel overviewThe most important structure along the new high-speed railway line between Graz and Klagenfurt is the Koralm Tunnel. The tunnel length of 32.9 km is divided into three contracts, which will mostly be driven in a continuous process (contract KAT2 in Styria, contract KAT3 in Carinthia), with an excavated cross-section of about 82 m 2 . In accordance with the European safety standard (TSI), the two parallel single-track running tunnels will be linked every 500 m with crosscuts, with an additional emergency halt approximately in the middle of the tunnel.In order to obtain detailed geotechnical knowledge for the planning of mechanical tunnelling, extensive investigation measures were undertaken in the location of the top heading of the later southern bore. In order to achieve representative cover of the geological conditions, a shaft was sunk at Paierdorf ( Fig. 1) in the section of contract KAT3 with deep overburden in addition to the starting points with shallow overburden (West portal, intermediate starting point at Mitterpichling). The Paierdorf investigation tunnel was excavated in both directions from this shaft. The top heading, with a clear excavation area of approx. 40-50 m 2 , was excavated in the neogenic and through the fault zones with a temporary top heading invert.The transition from the neogenic to the crystalline, which is marked by a pronounced fault tectonic, the Lavanttal main fault zone, is the main focus of investigation for contract KAT 3. The tunnelling work undertaken during the investigation programme is mostly complete. At the moment, the eastward drive of the investigation tunnel towards the contract boundary is still underway, but has already passed through the Lavanttal main fault zone and is now in the crystalline section of the Koralpe. Koralmtunnel ÜberblickDas Hauptbauwerk der neuen Eisenbahn-Hochleistungsstrecke zwischen Graz und Klagenfurt bildet der Koralmtunnel. Die Tunnellänge von 32,9 km ist unterteilt in drei Baulose, die überwiegend im kontinuierlichen Vortriebsverfahren (Baulos KAT2 Steiermark, Baulos KAT3 Kärn-ten), mit einem Ausbruchquerschnitt von rund 82 m 2 aufgefahren werden. Dem europäischen Sicherheitsstandard (TSI) entsprechend werden die beiden parallel verlaufenden Einspurtunnel alle 500 m durch Querschläge verbunden; etwa in Tunnelmitte wird eine Nothaltestelle eingerichtet.Um detaillierte geotechnische Erkenntnisse für die Planung der Maschinenvortriebe zu erlangen, wurden umfangreiche Erkundungsmaßnahmen im Kalottenbereich der späteren Südröhre ausgeführt. Zur repräsentativen Abdeckung der geologischen Verhältnisse wurde zusätzlich zu den Angriffstellen mit...

Criteria for the selection of tunnelling method through the example of the Koralm Tunnel / Kriterien zur Wahl der Vortriebsarten am Beispiel des Koralmtunnels

“…Therefore, a shield machine with earth pressure components was favoured as a solution (SM-V5). In the area of the tertiary sediments, this machine offers the possibility of working -depending on the geological and geotechnical conditions -in different operating modes ("open", "transition" and "closed" modes) to ensure safe face conditions at all times [3]. The machine is to be converted to a TBM with shield for the crystalline bedrock section.…”

“…Als Vorzugslösung wurde daher eine Schildmaschine mit Erddruckkomponenten favorisiert (SM-V5). Diese Maschine bietet im Bereich der tertiären Sedimente die Möglichkeit, je nach geologisch-geotechnischen Randbedingungen in unterschiedlichen Betriebsmodi ("open"-, "transition"-und "closed mode") zu agieren, um zu jedem Zeitpunkt sichere Ortsbrustverhältnisse gewährleisten zu können [3]. Für den kristallinen Festgesteinsabschnitt erfolgt ein Umbau zur TBM-S.…”