| Evaluation index | Grade | |||||
|---|---|---|---|---|---|---|
| grade I | gradeII | gradeIII | gradeIV | grade V | ||
| Characteristics of 3D geomat | Thickness of the geomat B11 (mm) | >16 | 14-16 | 12-14 | 10-12 | 8-10 |
| Tensile strength B12 (KN/m) | <1.0 | 1.0-1.5 | 1.5-2.0 | 2.0-2.5 | >2.5 | |
| Soil Nails Spacing B13 (m) | >3.2 | 2.2-3.2 | 1.5-2.2 | 0.8-1.2 | <0.8 | |
| The characteristics of soil | Cohesion of soil B21 (kPa) | >70.0 | 50.0-70.0 | 20.0-50.0 | 10.0-20.0 | <10.0 |
| Internal friction angle B22 (°) | >40.0 | 30.0-40.0 | 20.0-30.0 | 10.0-20.0 | <10.0 | |
| Bulk density B23 (KN/m3) | <12.0 | 12.0-16.0 | 16.0-20.0 | 20.0-24.0 | >24.0 | |
| Permeability coefficient B24 (cm/s) | 10-8-10-7 | 10-7-10-6 | 10-6-10-5 | 10-5-10-4 | 10-4-10-3 | |
| Compactness B25 (%) | 95-100 | 90-95 | 85-90 | 80-85 | 75-80 | |
| Ratio of pore pressure B26 | 0.45-0.5 | 0.4-0.45 | 0.35-0.4 | 0.3-0.35 | 0.25-0.3 | |
| The characteristics of slope | Slope angel B31 (°) | <25 | 25-45 | 45-65 | 65-75 | >75 |
| Slope length B32 (m) | >50 | 40-50 | 25-40 | 10-25 | <10 | |
| Lithology B33 | very good | good | moderate | bad | very bad | |
| The characteristics of vegetation | Vegetation coverage B41 (%) | >60 | 45-60 | 30-45 | 10-30 | <10 |
| Root development B42 | very good | good | moderate | bad | very bad | |
| Planting suitability B43 | very good | good | moderate | poor | very poor | |
| The characteristics of rainfall | Rainfall intensity B51 (mm/h) | <0.4 | 0.4-1.25 | 1.25-5.8 | 5.8-11.6 | >11.6 |
| Rainfall duration B52 (d) | <1.0 | 1.0-2.0 | 3.0-5.0 | 6.0-8.0 | >8.0 | |
| Daily rainfall capacity B53 (d) | <10.0 | 10.0-30.0 | 30.0-60.0 | 60.0-140 | >140.0 | |
| Construction and maintenance | Construction technique B61 | very good | good | moderate | bad | very bad |
| Maintenance condition B62 | very good | good | moderate | bad | very bad | |
| Maintenance time B63 (d) | >60 | 50-60 | 40-50 | 20-40 | <20 | |
| Environment | Temperature B71 (°C) | 25.0-30.0 | 20.0-25.0, | 10.0-20.0, | 0.0-10.0, | else |
| 30.0-35.0 | 35.0-40.0 | 40.0-45.0 | ||||
| Humidity B72(%) | >60 | 50-60 | 40-50 | 30-40 | <30 | |
| PH value B73 | else | 6.0-6.5, | 5.5-6.0, | 5.0-5.5, | else | |
| 7.5-8.0 | 8.0-8.5 | 8.5-9.0 | ||||