Abstract: This study investigates the physical and mechanical properties of soft soil in the Hengqin Extension of the Macau Light Rail and its surrounding regions, along with corresponding engineering countermeasures. By analyzing data from 220 soft soil samples through physical and mechanical tests and regression analysis, the primary characteristics of the soft soil, such as high water content, strong compressibility, and low shear strength, were identified. The influence of these characteristics on foundation pit engineering was also examined. The results show that for saturated soft soil, the water content has a strong correlation with other physical property indexes, consolidation indexes and unconfined compressive strength, and a relatively strong correlation with plasticity indexes except the plastic limit, but a weak correlation with shear strength parameters. Based on the findings, targeted engineering measures, including a diaphragm wall with internal bracing systems, soil reinforcement, and dewatering schemes, were proposed to mitigate the adverse effects of soft soil on deep foundation pit construction. This research provides a valuable reference for integrating theory and practice in construction projects within similar soft soil regions.

Key words: Soft Soil, Physical and Mechanical Properties, Regression Analysis, Engineering Measures