Geological and geotechnical surveys in the karst region of Northern Lithuania

Geological and geotechnical surveys in the karst region of Northern Lithuania

This region covers most of the territory of the Biržai and Pasvalys municipalities, slightly covering the territory of the Panevėžys district north of the city and is fragmented on the eastern edge of Radviliškis municipality. Construction here is risky, not only due to unexpected sinkholes, but also due to other karstic phenomena. However, the harmful effects are obviously notable after a few or several decades. It is  common to see eruptions in the area due to melting rocks or the weakening of the subsoil due to the formation of soil-forming particles or even soils into deeper heated rocks. Such processes cause  deformations of the structures standing on these soils, which can make the structure unusable.

Although geological and geotechnical surveys in this area are complex and expensive, no rationally minded person will invest in construction or expensive repairs without knowing what awaits underground. Geological and geotechnical surveys in the karst district of Northern Lithuania are regulated by STR 1.04.03: 2012 “Geological and geotechnical surveys in the karst district of Northern Lithuania”. According to this document:

• Summary of previous IGG research data • Karstological inspection using remote sensing data;
• Estimation of type, age, distribution patterns and intensity of karstic (karstic suffosive) phenomena • Geophysical surveys • Drilling of boreholes over the entire column of collapsed rocks, determination of geometry of engineering geological layers • Determination of height of detected karstic voids • Geotechnical testing of base soils • Laboratory tests to determine physical and mechanical properties of soils.

During the preparation for the survey, the company's specialists compile a survey work program, which is coordinated with the client and the Lithuanian Geological Survey, and the prepared geological survey report is submitted to the Lithuanian Geological Survey for assessment before submission to the client. The report presents the engineering geological conditions of the site, the prevalence of heated rocks and processes at the site and their forecast, providing an assessment, risks, and recommendations for construction works.