# Influence of Xanthan Gum-Based Soil Conditioners on the Geotechnical Properties of Soils
## 5 Conclusions  
Research confirmed that the addition of XG-based soil conditioners (SCs) affects the index properties, water absorption capacity, compressibility, drained shear strength, and hydraulic conductivity of the soil. The main function of the developed SCs is to increase soil water retention for plant growth. Therefore, the compressibility, drained shear strength, and hydraulic conductivity were determined on the saturated specimens of the untreated soils \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Soil**} & \multirow{2}{*}{\(\sigma_{\text{p}}^{\prime}\)**(**kPa**)} & \multicolumn{5}{c}{**k (m/s)**} \\  & & **S*** & **S***+SC\_R L** & **S***+SC\_R H** & **S***+SC\_CG H** & **S***+SC\_ZZC H** \\ \hline \multirow{3}{*}{S1} & 25 & \(9.9\times 10^{-7}\pm 3.9\times 10^{-7}\pm 3.9\times 10^{-7}\pm 2.6\times 10^{-8}\) & \(2.7\times 10^{-10}\pm 3.9\times 10^{-11}\) & \(4.7\times 10^{-10}\) & \(1.3\times 10^{-11}\) \\  & 50 & \(4.4\times 10^{-7}\pm 3.9\times 10^{-8}\) & \(3.1\times 10^{-7}\pm 3.9\times 10^{-8}\) & \(4.0\times 10^{-11}\pm 3.9\times 10^{-11}\) & \(1.1\times 10^{-10}\pm 3.9\times 10^{-11}\) \\  & 50 & \(3.9\times 10^{-8}\) & \(1.2\times 10^{-8}\) & \(6.8\times 10^{-13}\) & \(6.3\times 10^{-12}\) & \(1.8\times 10^{-12}\) \\ \hline \multirow{3}{*}{S2} & 25 & \(4.3\times 10^{-7}\pm 2.6\times 10^{-7}\pm 1.7\times 10^{-9}\) & \(2.6\times 10^{-10}\pm 3.9\times 10^{-10}\pm 1.0\times 10^{-9}\) & \(2.9\times 10^{-10}\pm 3.9\times 10^{-12}\) & \(2.9\times 10^{-10}\pm 3.9\times 10^{-12}\) \\  & 50 & \(1.7\times 10^{-8}\pm 3.9\times 10^{-8}\pm 1.7\times 10^{-9}\) & / & \(7.6\times 10^{-10}\pm 3.9\times 10^{-11}\) & \(6.2\times 10^{-10}\pm 3.9\times 10^{-11}\) \\ \hline \multirow{3}{*}{S3} & 25 & \(4.1\times 10^{-7}\pm 2.7\times 10^{-9}\) & \(7.9\times 10^{-10}\pm 1.4\times 10^{-11}\) & \(1.3\times 10^{-10}\pm 1.0\times 10^{-9}\pm 3.9\times 10^{-11}\) & \(2.6\times 10^{-10}\pm 3.9\times 10^{-11}\) \\  & 50 & \(1.7\times 10^{-8}\pm 3.6\times 10^{-10}\pm 3.7\times 10^{-12}\) & / & \(8.0\times 10^{-11}\) & \(1.6\times 10^{-11}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Saturated hydraulic conductivity of untreated soils and mixtures at effective vertical stresses of 25 kPa and 50 kPa (mean values with standard errors) (* represents the identification number of the untreated soil). and mixtures. Despite the presence of oxide ash and cellulose fibers in the soil conditioners, the strength and stiffness of the saturated treated soils are generally lower than those of the saturated untreated soils. This suggests that in wet environments, the water sensitivity of the XG dominates over the effect of the fillers. For the investigated untreated soils from various locations in Europe and the mixtures of the soils and the SCs, the following conclusions can be drawn:  
1. The addition of the SCs increased the liquid limit only for soils S2 and S3 with relatively low initial liquid limits, while for soil S1 with the highest initial liquid limit, the values remained approximately unchanged. 2. The increase in water absorption capacity due to the SCs was notable for all types of soils. The type of SC does not have a considerable impact on water absorption, but the dosage of the SCs and the soil type do. 3. The addition of the SCs leads to the swelling of the mixtures under low effective vertical stress, inherently affecting their compressibility. The analysis of the results highlights the importance of the dosage of the SCs, while the type of SC was not recognized as influential. This suggests that the compressibility of the mixtures is more influenced by the XG than by the fillers in the soil conditioners (SCs). 4. The presence of XG in SCs reduces the drained shear strength of treated soils in comparison with untreated soils. The reduction in the friction angle was observed to be dependent on the dosage of the soil conditioner (SC).