# Stabilization of Road Embarkments on Peat Soils Using Oil Shale Ash and Pozzolanic Additives
## Results and Discussion
### Mechanical Testing of the Specimens  
All the results of mechanical tests are summarized in Table 12 (see below). During the compression tests, the water content and density of the test body were determined. The density of the soil is characterized by the compression index C\({}_{\rm c}\). The water \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & ** Bag 1** & ** Bag 1** & ** Bag 1** & ** Bag 1** & ** Bag 2** \\  & **0–20 cm** & **21–40 cm** & **41–60 cm** & **>60 cm** & **0–20 cm** \\ \hline O & 37.1 & 48.2 & 47.8 & 47.3 & 28.5 \\ C & 30.2 & 6.28 & 9.29 & 6.88 & 12.8 \\ Ca & 12.7 & 29.2 & 31.0 & 28.5 & 5.75 \\ Si & 9.78 & 0.814 & 0.891 & 2.50 & 29.3 \\ K & 3.54 & 3.47 & 0.905 & 1.46 & 1.91 \\ Al & 1.24 & 0.244 & 0.239 & 3.37 & 3.88 \\ Mg & 1.11 & 2.08 & 2.19 & 1.94 & 0.687 \\ P & 0.987 & 0.941 & 0.992 & 0.856 & 0.379 \\ Fe & 0.984 & 0.205 & 0.208 & 0.430 & 2.91 \\ Mn & 0.702 & 0.766 & 0.764 & 0.781 & 0.137 \\ S & 0.646 & 0.415 & 0.184 & 0.375 & 0.240 \\ Cl & 0.401 & 0.141 & 0.0513 & 0.0770 & 0.0287 \\ Ba & 0.188 & 0.765 & 0.563 & 0.575 & 0.101 \\ Na & 0.173 & 6.18 & 4.55 & 4.61 & 1.08 \\ Zn & 0.0777 & 0.147 & 0.0896 & 0.243 & 0.0354 \\ Ti & 0.0764 & 0.0720 & 0.168 & 0.0758 & 0.182 \\ Zr & 0.0355 & 0.0619 & 0.0616 & 0.0654 & 0.0182 \\ Cr & 0.0197 & BDL & BDL & BDL & BDL \\ Zr & 0.0129 & BDL & BDL & BDL & 0.0228 \\ Rb & 0.0127 & 0.0089 & TR & TR & 0.0067 \\ Cu & 0.0062 & 0.0108 & 0.0107 & 0.0108 & TR \\ Ni & 0.0044 & 0.0072 & TR & TR & 0.0078 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Elemental compositions of the mineral part of samples presented in Table 10 in percent by weight. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **w 1** & \(\rho\) 2 & **\(\rho\)d 3** & **q 4** & **c\({}_{\rm u}\) 5** & **q\({}_{\rm u,\,res}\) 6** & **c\({}_{\rm u,\,res}\) 7** & **q 8** \\  & **\%** & **g/cm3** & **g/cm3** & **kPa** & **kPa** & **kPa** & **kPa** & **kPa** & **kPa** \\ \hline Soil-1 & 181.4 & 0.8 & 0.29 & 14 & 7 & 14 & 7 & 22 \\ Soil-2 & 181.6 & 0.75 & 0.27 & 12 & 6 & 12 & 6 & 19 \\ Soil-3 & 168.5 & 0.84 & 0.31 & 30 & 15 & 30 & 15 & 47 \\ AT-1 & 109.9 & 1.09 & 0.52 & 17 & 8 & 16 & 8 & 25 \\ AT-2 & 80 & 1.11 & 0.61 & 60 & 30 & 42 & 21 & 94 \\ AT-3 & 108 & 1.02 & 0.49 & 38 & 19 & 24 & 12 & 60 \\ T41-1 & 138.9 & 1.18 & 0.5 & 17 & 8 & 16 & 8 & 25 \\ T41-2 & 139.5 & 1.08 & 0.45 & 11 & 5 & 8 & 4 & 16 \\ T41-3 & 109.2 & 1.25 & 0.6 & 43 & 21 & 34 & 17 & 66 \\ T42-1 & 171.6 & 1.07 & 0.39 & 45 & 22 & 45 & 22 & 69 \\ T42-2 & 175.7 & 1.08 & 0.39 & 34 & 17 & 34 & 17 & 53 \\ T42-3 & 164.4 & 1.03 & 0.39 & 42 & 21 & 42 & 21 & 66 \\ T44-1 & 166.4 & 1.04 & 0.39 & 40 & 20 & 38 & 19 & 63 \\ T44-2 & 131.8 & 1.14 & 0.49 & 66 & 33 & 50 & 25 & 104 \\ T44-3 & 130.5 & 1.1 & 0.48 & 42 & 21 & 34 & 17 & 66 \\ \hline \hline \end{tabular} \({}^{1}\)—water content (of dry mass). \({}^{2}\)—density, \({}^{3}\)—dry density. \({}^{4}\)—undrained bearing capacity. \({}^{5}\)—undrained shear strength. \({}^{6}\)—residual undrained bearing capacity. \({}^{7}\)—residual undrained bearing capacity. \({}^{8}\)—bearing capacity.  
\end{table} 
Table 12: Undrained shear strength cu, undrained residual shear strength cu, and residual and bearing capacity q obtained as a result of uniaxial compression tests of 50 \(\times\) 50 \(\times\) 50 mm specimens. content and density were determined before and after compression, and the parameter \(\mathrm{C_{C}}\) was calculated. Based on the graph, \(\Delta\mathrm{h/h}=\mathrm{f}(\varepsilon)\), the overconsolidation ratio \(\varepsilon_{\mathrm{p}}\) was determined. During the tests, the water content was changed, reducing it from 400% to 250%. The calculated deformation modules were in the range of 0.3-0.7 MPa (see Figure 9); therefore, they indicate that the behavior of the material was at a compression exceeding the creep limit. The value of \(\varepsilon_{\mathrm{p}}\) was 90 kPa, slightly higher than that obtained from the plate load test (see below).