Czech D3 motorway: exploratory tunnel drilling starts near Benešov

In Czechia, near the town of Benešov, crews have begun drilling the third exploratory tunnel needed for one of seven tunnels planned for the future D3 motorway. According to the Road and Motorway Directorate (ŘSD), the geological survey work, costing CZK 248 million, will run until October 2027, while construction of the motorway itself is due to start in 2028.

Why the survey is needed

Transport Minister Ivan Bednárik (SPD) commented on the project, saying the Central Bohemian section of the D3 is needed to complete the motorway link between Prague and South Bohemia and relieve the region's overloaded roads.

“We are now starting to drive the third exploratory tunnel for the future tunnels — there will be seven of them in total on the Central Bohemian section of the D3,” the minister said. According to him, inadequate geological surveying is often the “Achilles' heel” of transport construction projects. “That's why it matters that here we're really going in depth,” Bednárik noted, adding that this will give ŘSD more detailed data on construction conditions and help it avoid complications and extra costs.

What the tunnel will reveal

The exploratory tunnel will be 838 metres long, with drilling reaching a depth of up to 42 metres. Available data suggest builders may encounter heavily and unevenly weathered rock, as the rock mass in this spot is badly fractured. According to ŘSD director Radek Mátl, the exploratory tunnel will help identify unstable zones where rock blocks could collapse.

The geotechnical data gathered will form the basis for decisions on how to shore up the tunnel, as well as the drilling technology and lining design for the future tunnel. Two similar exploratory tunnels are already under construction in the Posázaví area, near the town of Jílové.

Scale of the future route

Once complete, the missing Central Bohemian section of the D3 will run 58.5 kilometres. It will start near the town of Jesenice, where it will connect to the Prague ring road, then run south past Jílové, Hostěradice, Václavice, Voračice and Nová Hospoda. A six-kilometre Václavice connector road will link it to the town of Benešov and the existing road I/3.

The project includes, among other things, 51 bridges, 14 overpasses, seven tunnels and noise barriers totalling 17.1 kilometres in length. The estimated cost already exceeds CZK 71 billion. ŘSD expects traffic on the new route to open four years after construction begins — that is, in 2032. So far only half of the land plots needed for the project have been purchased.

Around Prague, based on reporting by novinky.cz