## 2 Methodology and Interpretation of Dilatometer Tests
#### Geotechnical Conditions of Test Sites  
This paper presents the test results of mineral and organic subsoil obtained from Antoniny and Koszyce sites located in the Notec river valley in the Wielkopolska province, Nielisz site located in the Wieprz river valley in Lublin province, the SGGW Campus with the Department of Geotechnical Engineering SGGW, and the Stegny site located in Warsaw, where a laboratory and field testing programme has been carried out under and outside of the main dam embankment [26; 27; 28]. The location of all analyzed objects is shown in Figure 5. The grain size distribution curve obtained from laboratory tests for mineral soil from the described sites is presented in Figure 6.  
Figure 5: Location of test sites in the region of Poland. Figure 6: Grain size distribution curve obtained from laboratory tests for the mineral soils from the described sites. The Antoniny test embankment was designed and performed in the frame of cooperation between the Department of Geotechnical Engineering SGGW and the Swedish Geotechnical Institute (SGI). The physical properties of the soil at the Antoniny site were determined during previous WULS-SGGW tests. The peat and gyttja layers have a thickness of 7.5 m; the ground is preconsolidated with the overconsolidated ratio \(OCR\) at 3-5 for peat, and 1.5-2.5 for gyttja [29; 30; 31]. The embankment was located in the Notec river valley on organic sediments, which contain two layers: peat with a thickness of 4.1 m and gyttja with a thickness of 3.7 m. Generally, the organic subsoil is composed of amorphous peat with varying carbonate gyttja, and variable content of organic matter and calcium carbonate. In the amorphous peat, the content of organic parts \(I_{om}\) ranges from 65% to 75%, the content of calcium carbonate CaCO\({}_{3}\) is equal to 10 \(\div\) 15% at moisture \(w_{n}\) between 310 and 340%, and the determined liquidity limit \(W_{L}\) is 305 \(\div\) 450%. The unit density \(\rho\) is 1.05 \(\div\) 1.10 g/cm\({}^{3}\), when the specific density is \(\rho_{\rm s}\) = 1.45 \(\div\) 1.50 g/cm\({}^{3}\). In the calcareous gyttja, the content of organic parts \(I_{om}\) ranges from 5% to 20%, the content of calcium carbonate CaCO\({}_{3}\) is equal to 65 \(\div\) 90% at moisture \(w_{n}\) between 105 and 140%, and the determined liquidity limit \(W_{L}\) is 80 \(\div\) 110%. The unit density \(\rho\) is 1.25 \(\div\) 1.40 g/cm\({}^{3}\), whereas the specific density \(\rho_{\rm s}\) = 2.2 \(\div\) 2.30 g/cm\({}^{3}\)[26; 27; 28] (Table 3). The Koszyce test dam was located in the Ruda river valley. A subsoil layer of soft organic soils was discovered in the central part of the dam. The organic soils are Quaternary deposits of an oxbow lake. The thickness of organic soils in this region generally exceeds 10 m and locally even 20 m. Dense sand occurs under the organic soils. The upper organic soils in the test area consist of a 2.5 m thick peat layer on the top of a 10.5 m thick gyttja layer underlain by a sand layer. In the amorphous peat, the content of organic parts \(I_{om}\) ranges from 70% to 85% and the content of calcium carbonate CaCO\({}_{3}\) is equal to 5 \(\div\) 15% at moisture \(w_{n}\) between 400% and 550%, and the determined liquidity limit \(W_{L}\) is 450%. The unit density \(\rho\) is 1.05 \(\div\) 1.10 g/cm\({}^{3}\), at the specific density \(\rho_{\rm s}\) = 1.45 \(\div\) 1.50 g/cm\({}^{3}\). Based on the index properties, the gyttja layer was sub-divided into three layers, the first one with a thickness of 2.5 to 6.3 m. In the calcareous gyttja (\(G_{y}\)), the content of organic parts \(I_{om}\) ranges from 10% to 20% and the content of calcium carbonate CaCO\({}_{3}\) is equal to 65 \(\div\) 80% at moisture \(w_{n}\) in the range of 120% and 160% and the determined liquidity limit \(W_{L}\) is 80 \(\div\) 110%. The unit density \(\rho\) is 1.20 \(\div\) 1.35 g/cm\({}^{3}\), at the specific density \(\rho_{\rm s}\) = 2.1 \(\div\) 2.25 g/cm\({}^{3}\).