By rosebell
In order to constructing the tunnel on Poland’s S19 highway, the TBM has been commissioned.
Being located between Rzeszów Południe and Babica, a two-lane 2.2km tunnel is due to be dug by TBM Karpatka, While building of 15 cross-passages and an emergency passage,as well as two technical buildings and a tunnel management centre, will be up to Acciona and Mostostal Warszawa consortium.
As part of a new 10.3km section of road, for constructing this tunnel TBM, which weighs 4,000 tons, 112m long and has a diameter of more than 15m, will work at a maximum depth of 100m beneath the Grochowiczna hill.
Considering that for facing challenges of what is one of the most technologically advanced infrastructure projects in the country, this machine has been refurbished, the upgrade includes a geological prediction tool that allows data to be collected from the tunnel face without the need for drilling.
According to Jorge Calabuig Ferre, vice-president of Mostostal Warszawa: “I am pleased to confirm that after adapting the TBM machine for potential methane conditions, the tunnelling process has started and is safe.”
In July last year, gas was detected during test pumping to lower the water table for tunneling. Methane appeared in two of the 44 well holes.
In order to working on addressing the issue, a team of specialists from the contractor and client, along with experts from the AGH University of Science and Technology in Krakow, the Higher Mining Authority in Katowice, and the District Mining Office in Krosno,were gathered.
As methane emission was important issue during the excavation, TBM had to be prepared and mining experts required the installation of methane detection sensors and a modified, high-efficiency ventilation system to prevent gas accumulation. Parts of the machine were also replaced with equipment suitable for methane conditions.
The location of manufacturing tunnel segments were the construction site in Lutoryż, wheras the production facility houses four cranes, the largest with a 60-ton capacity, and a concrete plant. More than 2,230 rings will be used for the tunnel lining.
The scheduled date for completing first bore by TBM is almost nine months, and it is slated to take around three months to turn the machine for it to begin drilling the second lane of the tunnel.
