Decoding Geotechnical Jargon: 100+ Abbreviations

Geotechnical engineers talk amongst themselves using abbreviations that are hard to decipher by project stakeholders and even engineers from other trades. In this compilation, we present the tip of the iceberg of such geotechnical engineering jargon. Readers who are not familiar with the abbreviations are invited to search online for more detailed information on what they mean. Finally, while this jargon is geared toward North American practice, most practitioners around the globe should be familiar with the Unified Soil Classification System (USCS).

100+ Abbreviations Geotechnical Engineers Use

1. ACIP - Auger Cast-in-Place Pile

2. ACDP - Auger-Cast Displacement Pile

3. APGD - Auger-Pressure-Grouted Displacement (pile)

4. ASD - Allowable Stress Design

5. BMPs - Best Management Practices

6. BOF - Bottom of Foundation

7. CBR - California Bearing Ratio

8. CFA - Continuous Flight Auger (Pile): The same as an Auger Cast-in-Place Pile (ACIP).

9. CPT - Cone Penetration Test

10. CD - Consolidated Drained (triaxial test)

11. CMT - Construction Material Testing

12. COV - Coefficient of Variation

13. CU - Consolidated Undrained (triaxial test)

14. DEM - Discrete Element Method

15. DFI - Deep Foundations Institute (https://dfi.org/)

16. DGWD - Design Groundwater Depth

17. DIGGS - Data Interchange for Geotechnical and Geoenvironmental Specialists.

18. DST - Direct Shear Test

19. e: Void ratio

20. EGS - Existing Grade Surface

21. FDP - Full-Displacement Pile

22. FEM - Finite Element Method

23. FOS - Factor of Safety

24. GEOR - Geotechnical Engineer of Record

25. G-I - Geo-Institute (of ASCE) - https://www.geoinstitute.org/

26. GI - Ground Improvement

27. GM - Ground Modification

28. GWT - Groundwater Table: Typically, refers to the depth of the groundwater at a site.

29. IGM - Intermediate Geomaterials: Transition materials between soils and rocks.

30. ISSMGE - International Society for Soil Mechanics and Geotechnical Engineering (https://issmge.org/)

31. LEM - Limit Equilibrium Method

32. LL - Liquid Limit

33. LRFD - Load and Resistance Factor Design

34. LSD - Limit State Design

35. MASW - Multi-Channel Analysis of Surface Waves

36. MPC - Modified Proctor Compaction

37. MSE - Mechanically Stabilized Earth

38. MDD: Maximum Dry Density

39. MSL - Mean Sea Level

40. MWD - Monitor (or Measure) While Drilling

41. n: Porosity

42. NC - Normally Consolidated (clay)

43. OC - Over-consolidated (clay)

44. OCR - Over-consolidation Ratio

45. OMC - Optimum Moisture Content

46. PBD - Performance Based Design

47. PDA - Pile Driving Analyzer

48. PI - Plasticity Index

49. PL - Plastic Limit

50. PLT - Pile Load Test

51. PLT - Point Load Test

52. PPT - Pocket Penetrometer Test

53. RAP - Rammed Aggregate Pier

54. RBD - Reliability (or Risk) Based Design. We prefer reliability 👍.

55. RC - Relative Compaction (=field dry density divided by maximum dry density, expressed as a percentage)

56. RCT - Resonant Column Test

57. RI - Rigid Inclusion

58. RQD - Rock Quality Designation

59. SCPT: Seismic Cone Penetration Test

60. S: Degree of saturation

61. SL - Shrinkage Limit

62. SOE - Support of Excavation (system)

63. SOG - Slab on Grade

64. SPC - Standard Proctor Compaction

65. SPT - Standard Penetration Test

66. SRF - Stress Reduction Factor

67. SSA - Slope Stability Analysis

68. SSD - Saturated Surface Dry (of an aggregate)

69. SSI - Soil-Structure Interaction

70. SWPPP - Storm Water Pollution Prevention Plan

71. TBM - Tunnel Boring Machine

72. TOC - Top of Concrete (elevation)

73. UC - Unconfined Compression (test)

74. USCS - Unified Soil Classification System: a system to classify soils into:

    1. CH: Fat Clay

    2. CL: Lean Clay

    3. CL-ML: Silty Clay

    4. GC: Clayey Gravel

    5. GC-GM: Silty, Clayey Gravel

    6. GM: Silty Gravel

    7. GP: Poorly-graded Gravel

    8. GP-GC: Poorly-graded Gravel with Clay

    9. GP-GM: Poorly-graded Gravel with Silt

    10. GW: Well-graded Gravel

    11. GW-GC: Well-graded Gravel with Clay

    12. GW-GM: Well-graded Gravel with Silt

    13. MH: Elastic Silt

    14. ML: Inorganic Silt

    15. OL: Low-plasticity Organic Silt or Clay

    16. OH: High-plasticity Organic Silt or Clay

    17. SC: Clayey Sand

    18. SC-SM: Silty, Clayey Sand

    19. SM: Silty Sand

    20. SP: Poorly-graded Sand

    21. SP-SC: Poorly-graded Sand with Clay

    22. SP-SM: Poorly-graded Sand with Silt

    23. SW: Well-graded Sand

    24. SW-SC: Well-graded Sand with Clay

    25. SW-SM: Well-graded Sand with Silt

75. USM - Unsaturated Soil Mechanics

76. UU - Unconsolidated Undrained (triaxial test)

77. VST - Vane Shear Test

78. ZAV - Zero Air Voids (curve, in compaction testing)