Environmental Disturbance Mechanisms and Ecological Protection Pathways in Shield Tunneling Construction

Amid rapid urban subway development, shield tunneling causes surface subsidence, threatening urban ecosystems. This study examines a 10.15 km project across pebble-sand and silty clay strata, combining field monitoring, statistics, and Gaussian fitting to analyze subsidence patterns and ecological impacts. Lateral subsidence troughs vary with stratum and load: pebble-sand yields “deep and narrow” troughs; silty clay forms “deep and narrow” under heavy load, “shallow and wide” otherwise. Longitudinal subsidence has three stages: initial adjustment, rapid settlement, and stabilization. Ecological effects show thresholds: ≤8 mm—no significant impact; 8–12 mm—slight, recoverable damage; >12 mm—significant or irreversible harm. Pebble-sand is more sensitive to groundwater changes; silty clay more prone to vegetation damage. The study clarifies the subsidence–ecological response mechanism, establishes a quantitative assessment framework, and supports stratum-specific ecological protection for green subway development.