Table 1 Categorized variables for high-speed rail subgrade defect analysis
Variable categories | Variable subclasses details | |
|---|---|---|
Climate variables | Average annual rainfall(mm) | |
Consecutive 5-day rainfall(mm) | ||
Number of days with maximum temperature exceeding 35 degrees Celsius(day) | ||
Annual freezing days(day) | ||
Wind speed (m s-¹) | ||
Geomorphological variables | Elevation (m) | |
Slope (°) | ||
Aspect (°) | ||
Geological variables | Rock hardness (Pa) | |
Soil composition | Clay(heavy), silty clay, clay, silty clay loam, clay loam, silt, powdery sandy loam, sandy clay, loam, sandy clay loam, sandy loam, loamy sand, sand. | |
Effective water storage capacity | The United Nations Food and Agriculture Organization (FAO) evaluates the capacity of soil units to store water at a specific depth, dividing it into 7 levels: 150 mm/m, 125 mm/m, 100 mm/m, 75 mm/m, 50 mm/m, 15 mm/m, and 0 mm/m. | |
Soil depth | For all soil units, the reference depth is typically set at 100 cm. However, for Rendzinas and Rankers in the FAO-74 classification, and for Leptosols in the FAO-90 classification, the reference soil depth is set at 30 cm; for Lithosols in FAO-74 and Lithic Leptosols in FAO-90, the reference depth is set at 10 cm, and also at 0 cm. | |
Drainage class | Excessively drained, well drained, moderately well drained, moderately drained, somewhat poorly drained, poorly drained, very poorly drained. | |
High-speed rail proximity index | Average distance to river (Km) | |
Average distance to lake (Km) | ||
Average distance to road (Km) | ||
Distance to fault (Km) | ||
Land use/Land cover | Cropland | Paddy fields, drylands |
Woodland | forested lands, shrublands, vegetable woodlands, other forested lands, | |
Grassland | high cover grassland, medium cover grassland, low cover grassland, | |
Water body | rivers, canals, lakes, reservoirs, permanent glacial snowfields, mudflats, beach land | |
Built-up land | urban land, rural residential, industrial and commercial construction land | |
Unused land | sandy land, gobi, saline and alkaline land, marshland, bare land, bare rock, other unused land, alpine desert, tundra, marine | |
High-speed rail operational characteristics | Operating frequency (Times/day) | |
Construction length (Km) | ||
Design speed (Km h-¹) | ||
Operating period (Day) | ||
Economic variables | Gross domestic product (RMB) | |
Population (Individuals) | ||
District or county area (Km²) | ||
Spatial lag | Settlement spatial lag value | |
Frost damage spatial lag value | ||
Uplift deformation spatial lag value | ||
Mud pumping spatial lag value | ||
