Investigation of Compressibility and Shear Strength Behavior of Soft Soil Stabilized by Bottom Ash and Waste Fishing Net

The aim of this study is to investigate the characteristics of a composite geomaterial (CGM) consisting of dredged clayey soil, bottom ash (BA), and waste fishing net (WFN). Laboratory experimental programs were conducted, encompassing physical tests, oedometer tests, and direct shear tests. The CGM specimens were prepared with varying BA contents (0%, 5%, 10%, 20%, and 40%) and WFN contents (0%, 0.5%, and 1%). The experimental results showed that the engineering characteristics of CGM were significantly improved by BA and WFN stabilization. Specifically, the compressibility index, derived from consolidation tests, decreased significantly with increasing BA content. The tangent compression modulus, evaluated from oedometer tests, depended not only on the stress levels but also on the BA content, with the tangent modulus being less dependent on BA amounts at low stress levels. The addition of BA and WFN enhanced the shear strength of CGM, with WFN exerting a more pronounced influence. The consolidation coefficient exhibited a linear correlation with BA content, and a regression equation was proposed to describe this relationship. Additionally, CGM samples with WFN content demonstrated higher consolidation coefficients compared to those without WFN. The study demonstrated the potential application of CGM with BA and WFN in geotechnical engineering.