Sustainable Engineering of Fiber-Reinforced Coal Gangue Linking Geomechanics and Microstructure through Support Vector Machines

Abstract The periodic variations (heave/shrink) in soft soil can lead to extensive damage to lightweight structures, resulting in an annual loss of several billion dollars. Although well-known traditional stabilizers can effectively regulate soil volumetric stability and compressibility, their production can have a massive environmental impact. This paper investigates the geomechanical efficiency of soft soil reinforced with chemically treated banana fiber (CTBF) and EnviroSafe alkaline-activated materials (AAM), which are composed of alkaline solutions and industrial waste materials. The proportions of coal gangue ash (CGA) replacement with silica fume (SF : 0–20%) were varied in the alkaline solution by maintaining a 0.4 water-to-solid ratio. A series of consolidation compressive shear, and penetration resistance tests were performed to determine the geomechanical properties, including resilient modulus (MR), shear strength ratio, Stereoscopic, Fourier-transform infrared (FTIR) spectroscopy, and Thermogravimetry analysis (TGA) tests at varying CTBF-SF mixture dosages. The study proposed an optimal dosage of CGA-SF in AAM-stabilized soft soil. It demonstrated a substantial improvement in California Bearing Ratio (CBR) penetration and Unconfined Compressive Strength (UCS) tests. The results of silicafume (> 10%) in CGA-based AAM stabilizer soil attained the lowest equilibrium void ratio over the unreinforced soil. Furthermore, a support vector machine (SVM) algorithm model was proposed to predict the geomechanical strength of fiber-reinforced alkaline soil, and the results showed an excellent predictor of geomechanical strength performance.