This research explores, for the first time, the use of plastic waste to enhance the mechanical properties of Tunis soft clay, a soil known for its low stability. Soil samples mixed with 2%, 5%, and 7% plastic waste were subjected to pre-consolidation tests up to 80 kPa, followed by unloading. The results show a significant reduction in consolidation time and void ratio, along with an increase in undrained cohesion. The optimal percentage of 5%, higher than the commonly reported 4%, provides notable improvements for applications in foundations and embankments. This study opens new perspectives for better plastic waste management while offering an innovative solution to geotechnical challenges. However, further studies on implementation techniques, such as deep compaction, are needed to validate its practical application.

Extensive research has demonstrated that cement is one of the most effective materials for improving soil properties. Researchers have investigated cement-stabilized soil techniques from various perspectives, including microstructural evolution and mechanical performance. However, studies on cement-stabilized soils in seasonal frozen regions remain limited. This study thus explored the application of cement-stabilized soil in these regions, specifically examining the effects of freeze-thaw cycles on its microstructure and shear strength through scanning electron microscopy (SEM) and direct shear tests. The findings indicate that freeze-thaw cycles induce noticeable microcracks and pores, significantly increasing particle breakage and decomposition, which leads to a loose structure and severely compromises the soil's mechanical properties. Incorporating cement generates hydration products that form cementitious bonds between soil particles, significantly enhancing structural density and overall stability. This cement stabilization effectively mitigates the damage caused by freeze-thaw cycles, enabling the soil to maintain good shear strength even after such cycles. These findings underscore the importance of cement stabilization in improving soil performance under freeze-thaw conditions, providing a theoretical basis and technical support for foundation improvement in cold regions.

Edge-oxidized graphene oxide (EOGO) is a nano-sized material that is chemically stable and easily mixed with water due to its hydrophilic properties; thus, it has been used in various engineering fields, particularly for the reinforcement of building and construction materials. In this study, the effect of EOGO in soil reinforcement was investigated. When mixed with soil, it affects the mechanical properties of the soil-GO mixture. Various amounts of the GO (0%, 0.02%, 0.06%, 0.1%) were added into the sand-clay mixture, and their geotechnical properties were evaluated via multiple laboratories testing methods, including a standard Proctor test, direct shear test, compressibility test, and contact angle measurement. The experimental results show that with the addition of EOGO in soil of up to 0.06% EOGO, the compressibility decreases, the shear strength increases, and the maximum dry density (after compaction) increases.