Relationship Between the SPT values with Angle of shearing resistance, Compactness, and Relative Density
The relationship between the standard penetration test(SPT or N) values with angle of shearing resistance(ɸ), compactness, and relative density are as follows:
| SPT Values (N) | Compactness | Relative Density | Angle of shearing resistance(ɸ) |
| 0 – 4 | Very loose | 0 – 15 | <28° |
| 4 – 10 | Loose | 15 – 35 | 28° – 30° |
| 10 – 30 | Medium | 35 – 65 | 30° – 36° |
| 30 – 50 | Dense | 65 – 85 | 36° – 41° |
| >50 | Very Dense | >85 | > 41° |
Read More:
Penetration Tests and Soil Sample Exploration – MCQ