## 3 Results and Discussion
### Calcite Percentage Results  
The effects of SA and SA + MICP combinations on the amount of calcite precipitation in S1, S2, and S3 soil specimens treated by the injection method, depending on various SA ratios, are shown in comparison in Figure 11. In general, variations in calcite precipitation were observed with changing SA content. In the S1 soil, the highest calcite content was obtained at 1% SA, while in the S2 and S3 soils, more balanced and higher precipitation values were recorded between 1.5% and 2.5% SA ratios. These results indicate that, in addition to the amount of SA, the type of soil also plays a significant role in calcite precipitation. In the literature, soil improvement studies using the injection method have primarily reported data for specimens containing only the SA + MICP additive combination. While this combination successfully promoted calcite formation across all soil types, the amount of calcite produced varied depending on the type of soil. In the S1 soil, the calcite content ranged between 1.30% and 2.72%, representing the highest values among all soil types. This suggests that the S1 soil has a structure more conducive to biological precipitation and that microbial calcite accumulation via the injection method was more effective in this soil. In the S2 soil, the calcite content ranged from 1.36% to 1.58%, indicating that the method was still effective, although the level of mineralization was more limited compared to S1. For the S3 soil, the calcite content varied between 0.31% and 1.73%, showing that the effectiveness of the injection method in promoting calcite formation was lower in this case. Differencesin the pore structure, grain size distribution, and hydraulic conductivity characteristics of the soils are considered the main factors explaining the variation in calcite content. Figure 10: _Cont._  
Figure 10: UCS results of soil specimens improved by the mixing method. The results of SA + MICP combinations, applied with varying SA ratios and pellet amounts, on calcite precipitation in S1, S2, and S3 soil specimens enhanced by the mixing method are compared in Figure 12. Higher calcite contents were obtained at 0.5% and 1% SA ratios, particularly with 10% and 15% pellet contents. However, increasing SA and pellet ratios did not always result in higher precipitation; in some combinations, a decrease was observed. This indicates that achieving maximum calcite precipitation depends critically on selecting appropriate ratios of SA and pellet content. In the S1 soil, the calcite content ranged from 1.39% to 5.12%. This relatively wide range indicates that both low and high levels of mineralization are possible, suggesting that both the biopolymer and microbial activity functioned efficiently in this soil type. In the S2 soil, the calcite content was measured between 0.91% and 4.51%, indicating that although the maximum values were lower compared to S1, a significant amount of calcite accumulation still occurred. The S3 soil exhibited the lowest range of calcite content, varying from 0.90% to 3.84%. This finding suggests that while the mixing method was also effective in S3, the soil may present more limiting conditions, particularly in terms of porosity or the available surface area for bonding. SA + MICP combinations applied via the injection method have been observed to result in higher calcite accumulation, particularly in fine-grained soils. This suggests that the S1 soil offers favorable porosity and a binding surface area conducive to microbial precipitation. In a related study, it was reported that Ca-alginate polymeric gel effectively filled the voids in sandy soils containing limestone, thereby narrowing water flow paths and significantly enhancing low hydraulic conductivity [28]. This condition also increases the efficiency of biological precipitation. Nevertheless, the mixing method allows for a more homogeneous distribution of additives within the soil, and when supported by a high pellet content, it can lead to a wide range of calcite precipitation.