Laser-Induced Breakdown Spectroscopy-Based Assessment of Unconfined Compressive Strength of Normal and Chemically Stabilized Soils

Laser-induced breakdown spectroscopy is a remarkable elemental detection and quantification technique employed in various sectors such as science, engineering, medicine, and construction. This work investigates the physical and mechanical properties of normal and chemically stabilized soils using LIBS and single linear regression analysis. In addition, the work proposes an alternative approach to soil assessment using electromagnetic waves instead of conventional laboratory measurements. Initially, the dominant chemical elements of different soils were investigated using LIBS. The resulting intensities of the elements were then correlated with the results of a standardized soil unconfined compressive strength measurement. Based on the obtained results through one-element linear regression, it was found that the performance of universal correlations varies greatly for the individual soil specimens. This can be attributed to the fact that there is a large variation from one soil to another in terms of chemical composition. The peak analysis indicated that the dominant peaks of 251.92, 279.8, 383.83, 396.15, and 422.67 nm are common for the investigated soil samples. Our investigations revealed that the accuracy of the correlations is not controlled by the stabilizing agent, dosage, or curing age but rather by the chemical composition of the soil.