Geotechnical surveys of roads and railway lines

GeoStudio Bulgaria Ltd. has extensive experience in geological surveys of roads and railway lines, not only in the Republic of Bulgaria, but also abroad. For this type of construction, the beneficiaries under the Transport operational program are the National Railway Infrastructure Company and the Road Infrastructure Agency, with whom we have successfully completed projects. By their nature, these projects are of the “linear type” – on a predetermined route, new or existing, geological surveys are carried out at certain points along the route, through which the geological structure and the bearing capacity of the ground base are clarified.

Penetration tests along the Harmalni - Svilengrad railway line

We have dynamic penetrometers and software products that allow us to field determine the Californian bearing ratio – CBR.

Plate load test of fighter jet apron at the Graf Ignatieovo airbase

We use plate loading equipment when accurate information about the deformation modules of the ground base is required. In case the results do not meet the regulatory requirements, we design stabilized soil mixtures.

Measuring the thickness of the layers of the road structure and determining the suitability of the ground base on site

In projects for the rehabilitation of road sections, it is required to determine on site the thickness of the layers of the road structure, the CBR index and the modulus of elasticity of the contact between the road surface and the natural terrain.

Inspection of cracks and leaks in the Echemishka tunnel and measurement of the dip and strike of the layers of the southern tunnel portal on the Provadia - Aytos road

Our team conducted thorough inspections of the Hemus and Echemishka tunnels. At the request of the designers, the cracks and leaks for each reinforced concrete section were photographed and described. Based on the results of the study, the projects for the rehabilitation of the two tunnel pipes in the direction of the city of Varna were drawn up.

 

In the project for the rehabilitation of the Provadia – Aytos pass, one of the most problematic sections was a rock tunnel without lining in a pre-accident condition. Thanks to the detailed measurements of the slope and direction of the cracks and strata, as well as the study of rock samples for compressive strength, we determined the geotechnical condition of the massif using the RMR (Rock mass rating) methodology, and the designers took measures to reinforce the dangerous facility.

Falling head filtration test in piezometer borehole along the Sofia-Pernik-Radomir railway line

The determination of the hydrogeological parameters is no less important than that of the geological layers. This is especially true when it comes to the construction of important transport facilities such as new railway bridges. When we know these indicators, we are able to determine the expected inflow of water into the excavations and take measures to drain them even before the excavation works begin.