The construction of the city-tunnel Leipzig, which opened in Dezember 2013, was one of the largest inner-city infrastructure projects in Germany. It is the centerpiece of the central German suburban railway network and connects the two historically grown terminus stations Leipzig Central Station and Bavarian Station. For this, two tunnel tubes with a diameter of approx. 9 m were drilled on a distance of 3,5 km in shield tunneling.
The tunnel drive started at the central train station and ended in the Leipzig Market station, where an open excavation pit was built for this, in which the tunnel drilling machine could enter via the sealing block south. Subsequently, the tunnel drilling machine was converted to extend over the sealing block north in the direction of Wilhelm-Leuschner Platz.
During the tunneling process, the compensation grouting method (CGV) was used to continuously balance the resulting settlements and, as a result, to protect the existing status of the listed buildings of Leipzig city center guaranteed.
For the construction of a 60 m long tunnel under existing buildings, a foundation ground freezing was also carried out. For this purpose, a total of 114 horizontal boreholes were built for the installation of the icing lances. Subsequently a volume of about 4.800 m3 was iced up with the aid of liquid nitrogen.
- creation of quality assurance plan
- concept design of sample column manufacturing
- surveying and evaluation of the sample columns
- construction supervision of the jet grouting works
- supervision of the buildings to be underpinned
- project-supporting subsoil approach
- follow-up management
- device-specific adaptation of the jet grouting rig to the project-specific boundary conditions
- planning of approx. 22.000 m of horizontal drilling to secure an area of 22.000 m2 with the compensation grouting method (CGV)
- planning of building protection measures with specifications for the injections
- on-site control of active building protection on 30 building complexes by the CGV
- preliminary design, design and performance planning for lifting injections, underpinnings and icing
- static calculation of frost volume
- thermal engineering calculations of ground freezing for plant dimensioning and frost volume development
- planning and supervision of 180 temperature sensors
- expert support including specifications for plant operation during the entire execution time (drilling, icing, onset)
- vibration measurements and vibration supervision at several buildings at the sheet pile wall installation in the area at the Bavarian railway station