# Laboratory Testing and Analysis of Clay Soil Stabilization Using Waste Marble Powder
## 4 Conclusions  
This study conducted an extensive experimental and modeling investigation on the stabilization of clay soils using marble powder waste. Various tests were conducted to analyze the effects on geotechnical properties such as strength (UCS and UPV). Advanced modeling techniques were also implemented to validate further and optimize the soil stabilization process. The major conclusions arising from this comprehensive study are:  
1. The incorporation of increasing amounts of WMP into clay soil increases specific gravity from 2.73 to 2.83, primarily due to increased soil density, void filling, and reduced air content. Additionally, marble dust waste stabilizer improves clay engineering properties by reducing the liquid limit from 62.2% to 31.8%. It also reduces the plastic limit from 29.6 to 15.5% with increasing WMP content. Marble powder particles occupy spaces between clay particles, reducing the plasticity index from 32.6% to 22.6%.
2. Marble powder stabilizes clay, increasing maximum dry density (MDD) values from 1.65 to 2.31 Mg/m\({}^{3}\), over 40% at 60% WMP content. WMP also reduces OMC values from 22.5% at 0% marble powder to 11% at 60 and 75% marble powder, making it useful for soil stabilization and engineering applications due to its high specific surface area and pozzolanic activity.
3. After 28 days of curing, the clay showed an increase in UCS as the maximum UCS of the specimens is attained at X5 (60%), with DMC, OMC, and WMC paths of 472 kN/m\({}^{2}\), 661 kN/m\({}^{2}\), and 540 kN/m\({}^{2}\), respectively. The best strength (661 kN/m\({}^{2}\)) is achieved at 22.5 percent OMC, 60 percent WMP, and 28 days of curing. The strength enhancement depends on factors such as WMP quality, clay mineralogy, and curing time. Unconfined compressive strength testing successfully evaluated stabilization effectiveness, whereas, after a 28-day curing test, maximum UPV values were seen in clay soil stabilized with marble powder, with X5 powder providing the maximum boost. We found the UPV to be 412 m/s at DMC, 849 m/s at OMC, and 561 m/s at WMC. This further verified the improved structural integrity of stabilized and unstabilized clay soils. UPV values increased with WMP addition, correlating well with UCS trends. Combined UCS and UPV testing provides comprehensive strength characterization.
4. This study analyzed the Pearson correlation matrix to determine the relationship between the input parameters and the ANN model's predicted UCS and UPV values. The results showed a positive correlation, indicating the model's effectiveness in predicting the strength of stabilized and unstabilized soil samples. Validation confirmed the model's accuracy in predicting strength, as the correlation coefficients are close to 1. Finally, the long-term performance of soil stabilized with WMP and the consequence of environmental elements, e.g., rainfall and temperature in applications such as foundations and road subgrades, could be the subject of future research.  
Funding: This paper received its funding from the Hunan Provincial Key Research and Development Program (2022 SK2082); Guizhou Provincial Major Scientific and Technological Program (2023-425). Data Availability Statement: Some or all data, models, or codes that support the findings of this study are available from the corresponding author upon reasonable request.  
This paper received its funding from the Hunan Provincial Key Research and Development Program (2022 SK2082); Guizhou Provincial Major Scientific and Technological Program (2023-425). The authors wish to acknowledge this support.  
On behalf of all the authors, the corresponding author states that there is no conflict of interest. This article does not contain any studies with human participants or animals performed by any of the authors.