The Soil Layer definition is used to specify the characteristics of the soil. Various models are available in OpenBrIM. Some input parameters are presented here according to correlation studies in the literature, but they should only be used for preliminary design.
Cohesionless Soil - No. of Blows, N60 (Corrected) & Relative Density [Terzaghi et al., 1996] | |
|---|---|
No. of Blows, N60 (Corrected) | Relative Density |
4-10 | Loose |
10-30 | Medium |
30-50 | Dense |
Cohesive Soil - No. of Blows, N60 (Corrected) & Consistency of Clay [Terzaghi et al., 1996] | |
|---|---|
No. of Blows, N60 (Corrected) | Consistency of Clay |
2-4 | Soft |
4-8 | Medium |
8-15 | Stiff |
General:
Soil Type[Cohesionless/Cohesive/Rock]: Specify the soil type. This only affects the 3D visual of the model.
Unit Weight: Specify the unit weight of the soil.
Cohesionless Soil - Unit Weight(γ) [Caltrans, n.d.] | |
|---|---|
Relative Density | Unit Weight (lb/ft3) |
Loose | 89-115 |
Medium | 108-127 |
Dense | 108-140 |
Cohesive Soil - Unit Weight(γ) [Caltrans, n.d.] | |
|---|---|
Consistency of Clay | Unit Weight (lb/ft3) |
Soft | 100-120 |
Medium | 110-130 |
Stiff | 120-140 |
Top of Layer Elevation: This parameter specifies the global elevation of top layer of the soil.
Bottom of Layer Elevation: This parameter specifies the global elevation of bottom layer of the soil.
Lateral:
Lateral Model[Soft,Clay(Matlock)/Sand(Reese)]: Specify the appropriate model for the soil material definition.
Undrained Shear Strength:
Cohesive Soil - Undrained Shear Strength (Su) [Peck et al., 1974] | |
|---|---|
Consistency of Clay | Undrained Shear Strength (lb/ft2) |
Soft | <1000 |
Medium | 1000-2000 |
Stiff | 2000-4000 |
Major Principal Strain at 50%:
Cohesive Soil - Major Principle Strain (ɛ50) [Matlock, 1970] | |
|---|---|
Consistency of Clay | Major Principle Strain |
Soft | 0.020 |
Medium | 0.010 |
Stiff | 0.005 |
Internal Friction Angle:
Cohesionless Soil - (Φ') - Angle of Internal Friction [American Petroleum Institute, 2000] | |
|---|---|
Relative Density | Angle of Internal Friction (deg) |
Loose | 29-30 |
Medium | 30-36 |
Dense | 36-41 |
Subgrade Modulus:
Cohesionless Soil - Subgrade Modulus [Reese and Van Impe, 2000] | ||
|---|---|---|
Relative Density | (kpy) - Below Water Table (lb/in3) | (kpy) - Above Water Table (lb/in3) |
Loose | 20 | 25 |
Medium | 60 | 90 |
Dense | 125 | 225 |
Axial:
Axial Model:
Possion’s Ratio of Soil:
Cohesionless Soil - Poisson’s Ratio (ν) [Das, 2007] | |
|---|---|
Relative Density | Poisson’s Ratio |
Loose | 0.20-0.40 |
Medium | 0.25-0.40 |
Dense | 0.30-0.45 |
Cohesive Soil - Poisson’s Ratio (ν) [Bowles, 1996] | |
|---|---|
Consistency of Clay | Poisson’s Ratio |
Soft | 0.40 |
Medium | 0.45 |
Stiff | 0.50 |
Shear Modulus: Correlation values of the Elastic Modulus are referenced from Das (2007). The Shear Modulus is calculated from the equation: G=E/(2(1+ν)) .
Cohesionless Soil - Elastic Modulus (Es) [Das, 2007] & Shear Modulus (G) | ||
|---|---|---|
Relative Density | Elastic Modulus (ksi) | Shear Modulus (ksi) |
Loose | 1.50-3.50 | 0.63 -1.25 |
Medium | 2.50-4.00 | 1.00-1.43 |
Dense | 5.00-8.00 | 1.92-2.76 |
Cohesive Soil - Elastic Modulus (Es) [Das, 2007] & Shear Modulus (G) | ||
|---|---|---|
Consistency of Clay | Elastic Modulus (ksi) | Shear Modulus (ksi) |
Soft | 0.60-3.00 | 0.21-1.07 |
Medium | 3.00-6.00 | 1.03-2.07 |
Stiff | 6.00-14.00 | 2.00-4.67 |
The ultimate shear stress (Skin friction):
Tip:
Tip Model:
Possion’s Ratio of Soil: Refer the same parameter under Axial Tab.
Shear Modulus: Refer the same parameter under Axial Tab.
The ultimate tip resistance:
Torsional:
Torsion Model:
Shear Modulus:
Torsional Shear Stress:
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