Comparative performance assessment of ecological restoration techniques for transmission line slopes: integrating geotechnical stability and ecological indicators

Ecological restoration of transmission line slopes is essential for infrastructure sustainability in mountainous regions, yet comparative assessments of restoration techniques are lacking. This study evaluated four restoration approaches—vegetation concrete (VC), hydroseeding (HS), ecological bags (EB), and natural restoration (NR)—over 24 months on a slope in the Three Gorges Reservoir area, China. Geotechnical indicators (shear strength, root tensile strength) and ecological indicators (vegetation coverage, Shannon diversity index, aboveground biomass, soil organic matter) were monitored throughout the experimental period. The VC treatment demonstrated superior performance, achieving the highest shear strength (45.8 kPa), root tensile strength (12.8 MPa), and vegetation coverage (82.3%), with a comprehensive evaluation score of 99.8, followed by EB (84.8), HS (72.8), and NR (42.5). Strong positive correlations were identified between ecological and geotechnical indicators (r = 0.963 for biomass–root tensile strength; r = 0.890 for coverage–shear strength), whereas a moderate correlation between Shannon diversity and geotechnical metrics (r = 0.496) suggested a trade-off between species diversity and structural stability. These findings provide quantitative guidance for selecting restoration techniques in transmission line corridor management.