Soil Layer [SIG]
- Dogukan Kilic
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 according to the definition of the soil material.
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 [API, 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: Specify the appropriate model according to the definition of the soil material.
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 for the Elastic Modulus are referenced from Das (2007). The Shear Modulus is calculated using the equation from the theory of elasticity: 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): This parameter is dependent on both the type of pile (e.g., driven piles or drilled shafts) and the characteristics of the soil. It is imperative that engineers input this value accurately and appropriately, taking into consideration the specific conditions of each project.
Tip:
Tip Model: Specify the appropriate model according to the definition of the soil material.
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: This parameter is dependent on both the type of pile (e.g., driven piles or drilled shafts) and the characteristics of the soil. It is imperative that engineers input this value accurately and appropriately, taking into consideration the specific conditions of each project.
Torsional:
Torsion Model: Specify the appropriate model according to the definition of the soil material.
Shear Modulus: Refer the same parameter under Axial Tab.
Torsional Shear Stress: For input values, The ultimate shear stress (Skin friction) for a pile can be used.
References
[API, 2000] American Petroleum Institute (2000). Recommended Practice for Planning, Designing, and Constructing Fixed Off-shore Platforms-Working Stress Design: Upstream Segment. API Recommended Practice 2A-WSD (RP 2A-WSD): Errata and Supplement 1, December 2002, chapter 6. American Petroleum Institute.
[Bowles, 1996] Bowles, J. E. (1996). Foundation analysis and design, pages 123,163. McGraw-hill New York, 5th edition.
[Caltrans, nd] Caltrans (n.d.). Geotechnical Manual - Soil Correlations — Caltrans. https://dot.ca.gov/programs/engineering-services/manuals/geotechnical-manual. Online; accessed 29 May 2024.
[Das, 2007] Das, B. M. (2007). Principles of Foundation Engineering, chapter 5, page 240. CL-Engineering, 6th edition.
[Matlock, 1970] Matlock, H. (1970). Correlation for design of laterally loaded piles in soft clay. In Offshore technology conference, pages OTC–1204. OTC.
[Peck et al., 1974] Peck, R. B., Hanson, W. E., and Thornburn, T. H. (1974). Foundation Engineering. New York: Wiley, 2nd edition.
[Reese and Van Impe, 2000] Reese, L. C. and Van Impe, W. F. (2000). Single piles and pile groups under lateral loading, chapter 3, page 93. CRC press, 2nd edition.
[Terzaghi et al., 1996] Terzaghi, K., Peck, R. B., and Mesri, G. (1996). Soil mechanics in engineering practice, chapter 2, pages 60,63. John wiley & sons,