Civil: Geoflex BB Trial

Geoflex BB Silicate 2-c Resin For Consolidation or Strengthening of Loose Surface

Location: Sudoměřice u Tábora, Tábor

IV. railway corridor is one of the main railway lines intersecting Czech Republic from north to south and as in the case of I., II. and III. railway corridor is currently under its gradual modernization. The main objectives of modernization of transit corridors in the Czech Republic is to increase the speed to 160 km/h and an increase of the traffic capacity or railroads (eg. double-track lines).

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Problem Definition

IV. railway corridor is one of the main railway lines intersecting Czech Republic from north to south and as in the case of I., II. and III. railway corridor is currently under its gradual modernization. The main objectives of modernization of transit corridors in the Czech Republic is to increase the speed to 160 km/h and an increase of the traffic capacity or railroads (eg. double-track lines).

In the framework of corridor section Sudoměřice u Tábora - Tábor was recently put into operation the first railway tunnel in the region - Sudoměřice tunnel with a length of 430 m, realized by conventional excavation method (NATM).

With regard to the total length of the tunnel, its position to existing roads and putting under occupied farmland tunnel is only accessible from both tunnel portals. The requirement of general investor (SŽDC a.s.) was to ensure stable access road for service / emergency vehicles and vehicles of the integrated rescue system to the northern portal of the tunnel. At a length of about 100 meters (the distance between the earliest possible entrance to the tunnel portal) would, if necessary, the vehicle moved along the tracks on the loose ballast surface. To increase its stability and strength designer proposed consolidation method of loose surface, called ballast-bonding, for which the silicate resin Geoflex BB was used.

Ballast-bonding

The method involves spraying of the surface of the track ballast using of a special two-component resin with optimized curing time.

Thanks to optimal viscosity of Geoflex BB remains only his proportionate part on the surface of ballast and the remaining volume flows by gravity deeper into the ballast. The resin is concentrated in the contact points between aggregates (bridge connections), forming a strong bond. Ballast structure is even after the application of Geoflex BB completely permeable for the surface water.

Thanks ballast-bonding technology surface /ballast is less compressible and keeps its compactness under all conditions. At the same time is increased its cohesion and strength, which is an advantage especially in the case of tracks laid on embankments or in curves, where under normal conditions significant deformation of ballast occures.

Due to the technical parameters of silicate resin Geoflex BB is increase of deformational characteristics of ballast material significant, but it is still possible, if necessary, to disconnect it in mechanical way and compact it again.

Geoflex BB has been developed for applications with the required lifetime exceeding 20 years and for work in the open field without risk of environmental contamination or groundwater contamination.

Ballast bonding with Geoflex BB resin

For application of the material Geoflex BB the pneumatic pumps for two-component resins are used, with typical output capacity of 10-20 liters / min. Lightweight spraying gun with articulated nozzle allows the comfortable application and guarantees an excellent final effect.

Required 300 m2 was treated by spraying in 14 hours and the surface could be practically immediately loaded. For consolidation of layer about 20-25 cm (Project Requirement) was tested and subsequently applied resin consumption 12 kg/m2 of Geoflex BB resin.