Chemicals injection secure Węgierska Górka tunnel
The S1 expressway on the section of the Węgierska Górka bypass is one of the key projects covered by the governmental National Road Construction Program for 2014-2023, will provide a fast connection on the route Bielsko-Biała - Polish-Slovak border.
As part of this project, theTD-1.1 and TD-1.2 tunnels will be excavated on the slope of the Barania Góra massif, in the area of the eastern slope of the Glinne hill, while the tunnels TD-2.1 and TD-2.2 will be excavated in the slope of the Barania Góra massif, in the south-eastern slope of the Żarek hill.
The tunnels are excavated using the NATM,the new Austrian method of tunnel construction, where the rock mass is an element of the supporting structure of the tunnel itself, and its pressure after the breach is to be reduced by making a preliminary tunnel lining, which is only a temporary protective lining that still allows for rock mass deformations and shifts. The primary lining is made of steel ribs (lattice), reinforced shotcrete, and anchors.
Right from the start, the TD-2 tunnel was excavated in very difficult geological conditions which, along with an unrecognized landslide, led in May 2021 to the collapse of the cap rock and the destruction of the lining of a 10-meter section of the TD-2.1 tunnel.
As part of the repair program to eliminate the effects of the caving, an injection was made from the ground through the rock by DN 32mm screws using DSI FIXORAPID to consolidate the caving roof above the tunnel.
A total of 16,200 kilograms of chemical adhesive were introduced to 72 holes. The injection fulfilled its task, safely eliminating the cave-in’s effects.
The chemical resin injection was carried out in the face of the TD-2 tunnel, with the holes arranged according to the current geological and hydrogeological situation. DSI PUR W was used for the injection, carried out in 2–4 m deep holes with injection pipes and standard DN 42mm packers.
The use of chemical injections in mining enhances safety, while the excavation under the lowered backfill without collapsing the roof layers, will result in better technical maintenance of the tunnel.
The proper selection of technology in combination with the appropriately selected chemicals produced by DSI Underground allowed for the safe excavation of the TD-2.1 and TD-2.2 tunnels in critical sections.
DSI supplied Hollow Bars R32 and R51, as well as OMEGA BOLT®.