geotechnical-engineering

name	geotechnical-engineering
version	1.0.0
updated	"2026-02-26T00:00:00.000Z"
category	engineering/marine-offshore
description	Domain expertise for offshore geotechnical analysis planning — soil classification, foundation design method selection, pile/anchor capacity, on-bottom stability, and scour prediction.
tags	["geotechnical","soil","foundation","pile","anchor","scour","offshore"]
platforms	["linux","macos","windows"]
invocation	geotechnical-engineering
depends_on	[]
requires	[]
see_also	["mooring-analysis","structural-analysis","marine-offshore-engineering"]
scripts_exempt	true

Geotechnical Engineering Skill

Offshore geotechnical analysis domain expertise for planning soil investigations, selecting foundation design methods, and sizing geotechnical elements (piles, anchors, mudmats, scour protection).

When to Use This Skill

• Planning a geotechnical analysis campaign
• Selecting bearing capacity or pile capacity methods
• Choosing anchor type for given soil and loading conditions
• Reviewing soil parameter derivation from CPT or borehole data
• Mapping standards coverage for geotechnical calculations

Soil Classification Systems

USCS (Unified Soil Classification System)

Symbol	Description	Typical su (kPa)	Typical φ' (°)
CH	Fat clay	20–200	—
CL	Lean clay	10–100	—
ML	Silt	5–50	25–30
SM	Silty sand	—	28–34
SP	Poorly graded sand	—	30–36
SW	Well graded sand	—	33–40
GP	Poorly graded gravel	—	35–42

Robertson CPT Classification (1990/2009)

Zone	Ic Range	Soil Behaviour Type
1	—	Sensitive fine grained
2	> 3.60	Organic soils / peat
3	2.95–3.60	Clays (clay to silty clay)
4	2.60–2.95	Silt mixtures
5	2.05–2.60	Sand mixtures
6	1.31–2.05	Sands (clean to silty)
7	< 1.31	Gravelly sand to dense sand

Method Selection Decision Tree

Bearing Capacity

Undrained (clay)?
  ├── Yes → Brinch Hansen general formula (DNV-RP-C212 Sec 5)
  │         Nc = 5.14 for strip, shape/depth/inclination factors
  └── No (sand) → Terzaghi/Meyerhof drained bearing capacity
                   Nq, Nγ from friction angle