Kramer tunnel

Kramer tunnel
	Construction site at the north portal
use	Road tunnel (under construction)
traffic connection	B 23 Garmisch-Partenkirchen bypass
place	Garmisch-Partenkirchen
length	3,609 m
Number of tubes	1
cross-section	92 m²
Largest coverage	300 m
construction
Client	Federal Republic of Germany
building-costs	€ 264 million
start of building	February 7, 2020 (exploratory tunnel April 29, 2011)
completion	End of 2024
planner	State Building Authority Weilheim, ILF Consulting Engineers ZT
location
Coordinates
South portal	47 ° 29 '20 " N , 11 ° 3' 38" E
North portal	47 ° 30 ′ 40 " N , 11 ° 5 ′ 27" E

Map with all coordinates: OSM | WikiMap

The Kramer tunnel is part of the new route under construction on the B 23 , the western bypass of Garmisch, which is intended to reduce the volume of traffic in the Garmisch-Partenkirchen district of Garmisch. The single-tube tunnel with two lanes is planned with a length of 3,609 meters. Once completed, it will be the third longest road tunnel in Germany . The ski racer Maria Höfl-Riesch has taken on the sponsorship of the tunnel.

history

The first plans for a bypass go back to 1978. Various variants were examined in a regional planning procedure in 1982, with only one variant being assessed positively, in which, however, part of the bypass road would have crossed an area used by the US armed forces. In 1990, after lengthy negotiations, the Americans agreed in principle to such a route under certain conditions. After the terrorist attacks of September 11, 2001, however, the Americans tightened their requirements for averting any terrorist threats, which would have made a route in this area massively more expensive. As a result, a variant of the route to the south portal of the tunnel, which had previously been rejected in the regional planning procedure of 1982, was included in the planning again. After the construction project had been pushed forward by the government of Upper Bavaria up to the planning approval decision , the Federal Nature Conservation Federation in Bavaria filed a complaint against it in November 2007. The reason for this was the planned structural interventions in the area of the Loisach and the landscape on the southern slope of the Kramerspitz . However, this action was dismissed by the Bavarian Administrative Court on June 23, 2009 .

geology

The tunnel is located on the northern edge of the Northern Limestone Alps . The mountains are defined by three different solid rock units. These are primarily the 210 million year old and shiny black main dolomite , as well as plate limestone and the so-called Kössen formation with chains of limestone and clay - and marlstone . The main dolomite formation represents the largest part of the mountain range, with a thickness or thickness of up to 1,000 m. In the course of the formation of the northern limestone Alps, this was pushed over the geologically more recent sequences of the plate limestone formations and Kössen formations.

In the Quaternary period, loose rock of the Kramer Plateau was deposited on the solid rock . These consist of glacial sediments and deposits in the form of talus and Mur deposits. Numerous channels enter the subsoil in the transition area from solid rock to loose rock and seep away there. Surface water flows directly into the Loisach .

In relation to the so-called aquifer , approx. 85% of the tunnel runs within a fissured aquifer as part of the solid rock mentioned above, i.e. exactly where mountain water is available. The remaining 15% of the tunnel runs through a pore aquifer, a mixture of solid rock and loose rock. The intersection of a tunnel with such water-bearing zones, especially to this extent, is a challenge for the tunnel builder and is considered an additional obstacle. In addition, there is the fact that the tunnel in the area of the loose rock zone, a particularly unstable area, has a groundwater level of approx. 45 meters above the tunnel floor. The water pressure here is up to 4.5 bar .

Artificial irrigation of hillside spring moors

As a preliminary work for the tunnel construction, a 2.8 kilometer long irrigation pipe was built in 2018. This runs from the Lahn Wiesbaden trench to the slope Mooren source in the region of Schmölzersees. This allowed the groundwater to be lowered, which means that the natural springs dry out during the construction period. However, the vegetation in the area of the moors is specially artificially irrigated during the construction period so that it is not damaged. All work is environmentally controlled. The artificial irrigation of the hillside spring moors is specially monitored and, if necessary, improved during the construction period.

Technical parameters

The tunnel has 13 crosscuts between the rescue tunnel and the tunnel itself. Seven of them are accessible and six are drivable (for emergency vehicles). Like the road tunnel itself, the rescue tunnel can be used by (emergency) vehicles due to its dimensions of 3.5 × 3.5 meters over its entire length. The maximum speed in the road tunnel is 80 km / h. The transit time is therefore 2 minutes 45 seconds. The tunnel is illuminated by 174 LED adaptation lights, ie lights at the ends of the tunnel and 479 day and night drive-through lights. The tunnel system is equipped with radio for rescue workers and is monitored around the clock.

The system has so-called longitudinal ventilation , i.e. fans above the driving area that move the air lengthways. 16 of them with 45 kW power each . There are two exhaust fans for smoke extraction, both with 400 kW power each. The rescue tunnel has positive pressure ventilation so that smoke cannot enter the rescue area. This consists of 2 axial fans with 15 kW each. There are also two operating buildings at the tunnel portals and a cavern center inside the mountain. The tunnel's power requirement is an average of 480 kW and a maximum of 1.6 megawatts. The energy is fed in redundantly, i.e. from several sources. This can cause one network to fail and another to continue operating.

The tunnel has an excavated cross-section of 92 m² (115 m² with base vault). The rescue tunnel is 29 m² (36 m² with base vault). The excavated volume of the road tunnel is approx. 375,000 m³ and that of the rescue tunnel approx. 130,000 m³.

Construction phase

Overview

The construction of the tunnel system can be divided into two phases.

On the one hand, in the first construction of an exploratory tunnel . This started on April 29, 2011 and was originally supposed to be completed in 2013. The majority of this tunnel, which will later serve as an escape route, was actually completed in this time frame. Due to problems with the mountains, however, 350 meters are currently missing in the middle of the tunnel. Details on this below.

On the other hand, the construction of the actual road tunnel. This was ceremoniously posted on February 7, 2020 . The road tunnel is Template: future / in 4 yearsexpected to be completed by the end of 2024 . It will be the longest road tunnel in the Free State of Bavaria and as of 2020 it will be number 3 on the list of the longest tunnels in Germany .

Road tunnel

The road tunnel is being built under the direction and supervision of the state building authority Weilheim and a working group consisting of the engineering offices Müller + Hereth, EDR and BUNG. In addition to the Kramertunnel consortium, the execution planning and the construction itself are carried out by two construction companies, namely the Austrian BeMo Tunneling GmbH and the Czech Subterra AS. The total costs are EUR 264 million. The building owner is the Federal Republic of Germany itself. The total length of the tunnel structure is around 3,609 meters with two lanes each 3.5 meters wide. There are also two safety strips, each 0.25 meters wide, and two emergency walkways, each 1.00 meter wide. 3,523 meters of the tunnel will be built using the mining method (blasting and excavator propulsion), as well as 75 meters using the open construction method on the south portal and a further 10 meters using the open construction method on the north portal. The road tunnel will be drilled from both sides, just like the rescue tunnel. The teams are divided into the north and south portal. There are currently eight teams consisting of 3 - 5 workers involved in the tunneling. In addition, two groups in the workshops and two groups of subcontractors who work in water protection. Blasting takes place three times a day at a depth of 1.5 meters. Work is carried out around the clock, seven days a week. At peak times, up to 200 people work on the tunnel. 1.2 million tons of rock are blasted from the mountain. 173 tons of explosives are scheduled for this. Once the tube ready ascended , the tunnel with 104,000 tons of concrete is boarded inside.

Exploration tunnel / rescue tunnel

In the course of a public tender, Marti GmbH Austria, as part of the Swiss Marti Tunnelbau AG, was awarded the contract to build a 3,703 meter long exploratory tunnel from 2011 to 2013, which was later to serve as a rescue tunnel at a distance of 45 meters from the road tunnel. The legally prescribed construction of rescue tunnels or two tunnels next to each other was decided in 2004 in a directive of the European Parliament .

The construction of the tunnel was carried out by the EKS Kramertunnel consortium under the authority of the Weilheim State Building Authority. The project was written by the Munich engineering office EDR and the Innsbruck-based ILF Consulting Engineers ZT. The construction cost was 21 million euros. The tunnel was from both sides of the mountain ascended . This involved blasting with a cross-section of 28 to 42 m². Geological fault zones such as the so-called thrust Kramer were using an excavator propulsion ascended . Cross-passage connections for the road tunnel that followed later were made with varying cross-sections of 45 - 71 m². Cavities were secured with reinforcement , shotcrete , anchors, spikes and steel arches. At the south portal, a tubular umbrella was made in loose rock. An extensive exploration program was part of the construction. This included subsoil exploration drillings, borehole tests, geophysical borehole measurements, laboratory tests, etc.

Interruption of work

In November 2011, problems with the breakthrough of the exploratory tunnel through water and loose rock became known. The construction work was therefore interrupted in March 2013. Until then, the exploratory tunnel had been driven 2763 meters in the south and 576 meters in the north. To complete the exploratory tunnel, only 348 meters were missing, where the problems with the loose rock existed.

In April 2013 it became known that the tunnel builders wanted to lower the water table, which is higher than the exploratory tunnel, in order to be able to dig the tunnel through the layer of loose rock. However, a new supplementary plan approval procedure was necessary for this, which opened up the possibility of new lawsuits being filed. The Bund Naturschutz announced such a lawsuit in 2014. This would have delayed the project further.

Even when the US armed forces announced in early 2015 that they would give up their premises in the Breitenau area by 2018, no changes to the plan were made. The military area was included in the plans from the 1990s as part of the bypass route for Garmisch, so that by reviving these plans, the Kramer tunnel could have been created in a shortened and cheaper variant.

The supplementary plan approval procedure was initiated on July 20, 2017. The planning approval decision was issued on July 27, 2017. After no complaints were received by September 18, 2017, it became legally binding. The funds were released on September 19, 2017.