## 6 Conclusions  
In conclusion, variables like cement and lime contents significantly influenced material properties. PCA captured significant variance, enabling visualization of relationships. At the same time, PCR leveraged dimension reduction for accurate prediction, sensitivity and causal insight offering a powerful approach for optimizing sustainable, high-performance cementitious mixtures. Based on the results of this research, it can be concluded that;  
1. The combination of 6% cement and 15% lime (by dry soil weight) yielded maximum improvements: UCS increased by 222.5% to 2670 kPa at 28 days, void ratio decreased by 58% to 0.25, porosity decreased by 49.5% to 0.19, pre-consolidation stress increased by 206% to 1088.92 kPa, and the compression index decreased by 58% to 0.20, and the compressibility modulus increased by 16% to 10,474.28 kPa compared to untreated soil (779 kPa UCS, 0.60 void ratio, 0.38 porosity, 355.63 kPa reconsolidation stress, 0.48 compression index, and 7048 kPa compressibility modulus). 2. A single principal component (PC1) explained the vast majority of variance in key consolidation parameters: 90.33% for void ratio, 98.32% for porosity, 99.32% for pre-consolidation stress, 99.75% for compression index, and 99.89% for compressibility modulus. This overwhelmingly indicates that the combined lime and cement stabilizer content is the primary driver of microstructural modification and densification, with secondary factors contributing minimally. 3. The PCR model achieved an R\({}^{2}\) of 0.700 and an RMSE of 103.4 kPa for UCS prediction. The PCR causality model showed marked improvement in predictive accuracy with curing time, with R\({}^{2}\) increasing from 0.687 at 7 days to 0.830 at 28 days, while RMSE decreased from 11.2 kPa to 7.8 kPa. Sensitivity analysis identified soil compressibility characteristics (PC1: void ratio, porosity, compression index) as the dominant influence on UCS (46% variance explained, \(\beta=-170.70\) at 28 days), with its negative effect intensifying progressively from \(\beta=-76.84\) at 7 days to \(\beta=-170.70\) at 28 days, confirming that reduced compressibility is the primary causal mechanism for strength gain. 4. The most significant UCS gain occurred between 7 and 14 days under optimal stabilization (15% lime, 6% cement), increasing by 40.4% (1584.62 kPa to 2250.42 kPa), compared to only an 18.5% increase from 14 to 28 days (2250.42 kPa to 2670 kPa). Concurrently, the PCR model's explanatory power (R\({}^{2}\)) improved from 68.7% at 7 days to 83.0% at 28 days, indicating that soil-stabilizer interactions become more deterministic and predictable with extended curing. 5. Resistance to strength loss, evaluated after 7 days of soaking following 7 days of curing compared to 14-day cured strength, increased substantially from only 9% for untreated soil to 76% for soil stabilized with the optimal combination (15% lime, 6% cement). This demonstrates the effectiveness of the formed cementitious bonds(C-S-H, C-A-H gels) in creating a water-resistant soil matrix with enhanced long-term performance under adverse environmental conditions. Methodology, H.L., R.C., and A.B.B. ; laboratory experiments, Z.A.T., and J.I.H. ; validation, I.H.U., R.C., and H.L. ; formal analysis, R.C., A.B.B., and Z.A.T. ; writing--original draft, J.I.H., Z.A.T., and I.H.U. ; writing--review and editing, I.H.U., A.B.B., R.C., and H.L. All authors have read and agreed to the published version of the manuscript. This paper receives its funding from Projects (5247042340, 42277175) supported by National Natural Science Foundation of China; Project (2023J)J0657, 2023J)J0666) supported by Hunan Provincial Natural Science Foundation of China; Guizhou Provincial Major Scientific and Technological Program (2023-425). The authors wish to acknowledge this support. Some or all data, models, or codes that support the findings of this study are available from the corresponding author upon reasonable request.