In order to evaluate overconsolidation ratio (OCR) of soil, the necessity to restore them as much as possible to in situ conditions appears, because sometimes when it is not taken into account, mistakes could be made while interpreting mechanical – strength properties of the soil. According to the work purpose, overconsolidation ratio of the investigated soil was set by performing odometer test and the obtained values were compared with the OCR calculated from cone and seismic penetration data. When the tests were performed and data analysed, it was found that OCR values depends on soil occurance depth, strength characteristics and stress conditions. The OCR values decreases with the declination of the depth. As many authors noted in the literature – the upper part of the soil is consolidated abnormally, thereby we can see that in our work. When results are evaluate, we can conclude that all of the analysed soils was overconsolidation. That was demonstrated by calculations according static penetration, oedometer test and seismic waves results. OCR values differences between the laboratory and field tests can show low quality of soil sampling, also due to correlations which was applied.

This article presents results of the test conducted on the undrained shear strength of till clayey soils of Eastern Lithuania, which are characterized by rigid and very stiff consistency and low plasticity. According to the classification of soils presented in LST EN ISO 14688–2:2018 Geotechnical Investigation and Testing – Identification and Classification of Soil − Part 2: Principles for a Classification, the tested soils are classified as sandy low plasticity clays. The undrained shear strength was tested using the triaxial compression (unconsolidated undrained) method. The test results showed that peculiarities of the particle size distribution had a crucial impact on the undrained strength of these soils, i.e. on the correlation of clay and fine silt fractions with the rest of soil components.

The purpose of the investigation is to assess local clay soils of different composition, physical state and mechanical properties as a base and construction material for establishment of landfills for radioactive waste. The investigations have been carried out for three clay soil types of different age and origin in order to assess the potential of this clay to be used for the establishment of engineering barriers, as well as the base and slopes of landfills. The investigations have been performed by laboratory and field methods for both the natural as well as the disturbed and compacted soils. In order to assess the soil to be used for fill-ins (aggregate), field investigations have been performed at a special test site. Changes in geotechnical features of the soils were observed at the test site in autumn and spring. Seasonal investigations enabled to assess the compacted clay soils according to changes of their features over time.

The undrained soil strength is specific to fine soils or to sands with a lot of fines. It is very important characteristic and the evaluation of accurate value is significant step. The undrained soil shear strength can be estimated directly in laboratory and indirectly in field using in-situ methods. The values of undrained shear strength estimated with different methods usually are different, sometimes very much. In geotechnical practice a lot of empirical equations are used to calculate undrained shear strength (cu), however it corrects only in specific conditions and can’t be used universally. The empirical factor (Nk), which is used in mentioned equations, varies in wide range. It depends on many factors. The research of glacial genesis fine soils (various moraines) is complicated because it specific grain size distributions and genesis. In this article we will study relation between different laboratory and field methods to estimate of undrained shear strength (cu) of till soils. For these purposes we will used upper Pleistocene, upper Nemunas formation till fine soils.

Road and foundation deformations in modern Lithuanian construction are one of the most important problems. Constantly rising conflicts between customers and builders due to poor quality of foundations show that Lithuanian road builders do not ensure proper quality of work, do not perform the necessary road foundations and research, do not carry out continuous control of their work. One such example was the construction of the Pagegiai wind farm in 2014÷2015. Improperly installed road and crane installation foundations have forced the wind power plant to stop working, which resulted in enormous losses. Additional cluster engineering geological surveys that included a full range of field and laboratory work made it possible to identify the causes of poor quality work and to properly assess the properties of substrates and primers that are important for safe foundation operation.