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Site and Geotechnical Assessment

6 weeks · 0 milestones

Produce a geotechnical assessment for a real or documented site, covering the soil and ground conditions relevant to a proposed development or construction activity. The assessment must include: a desk study summary using publicly available geological mapping and ground investigation data for the site (describing the geological setting, likely soil types, and any known geotechnical hazards), estimated soil parameters (bearing capacity, settlement potential, and groundwater conditions) with documented sources and assumptions, a foundation recommendation (type, approximate depth, and sizing approach) with rationale, identification of at least 2 geotechnical risks (e.g. differential settlement, slope instability, liquefaction potential) with recommended investigation or mitigation, and a statement of the additional site investigation required to confirm the desk study assumptions. Preferred proof: a geotechnical assessment for a real development site using real ground investigation data. Accessible alternative: desk study assessment using publicly available geological survey data (British Geological Survey for UK sites — free; USGS for US sites — free; equivalent national survey data available for most countries) for a real publicly documented site — the site must be named and the data source referenced. Proof artifacts: the desk study with geological data (analysis artifact) and the geotechnical assessment report with foundation recommendation (documentation artifact). Verification: a geotechnical engineer reviews the foundation recommendation — 'your assumed bearing capacity of X kPa — what investigation would you need to confirm that number for a real project?' — requiring you to identify the specific test methods and what results you would need.

Milestone map

Milestone map

3 milestones

Collect and Classify Subsurface Data

2–3 weeks (3–4 hrs/week)

Obtain subsurface investigation data for a real or realistic site scenario — borehole logs, trial pit records, cone penetration test (CPT) results, or Standard Penetration Test (SPT) data from a published case study, open engineering dataset, or academic geotechnical report. Classify the soils encountered using the Unified Soil Classification System (USCS) or British Standard BS 5930. For each major soil layer, record the classification, depth range, and key engineering properties (undrained shear strength, friction angle, unit weight, plasticity index where relevant). Data collection is the critical gate — an assessment built on unclassified or misclassified soils will produce incorrect bearing capacity and settlement estimates.

Proof required

Submit your subsurface data log (≥2 boreholes or ≥3 CPT/SPT test points from a real site, published case study, or open dataset) and soil classification table (each layer classified to USCS or BS 5930, with depth, key properties, and data source cited).

What gets checked

  • ≥2 data sources (boreholes, CPT, SPT) are used — not single-point characterisation
  • Each soil layer is classified to the named standard (USCS or BS 5930) — not just described by colour or texture
  • Key engineering properties are cited with their data source — not assumed

Common mistakes

  • Using a single borehole and extrapolating across the site — one borehole rarely captures the site variability that controls foundation design
  • Soil properties assumed from textbook ranges without citing a specific data source for the site — geotechnical assessment must use site-specific data, or explicitly justify using published correlations where site data is unavailable

Resources

Foundationstart here

Depthgo deeper

What a verifier looks for

  • Confirm ≥2 subsurface data sources are used — flag single-point characterisation.
  • Confirm each soil layer is classified to USCS or BS 5930 — not just described informally.
  • Confirm all key engineering properties cite their source — flag assumed values without attribution.

Calculate Bearing Capacity and Settlement

3–4 weeks (4–5 hrs/week)

Using the soil classification and properties from M1, perform two foundation design calculations: (1) ultimate bearing capacity using Terzaghi's bearing capacity equation or EC7 equivalent, for a trial foundation geometry, applying appropriate safety factor or design approach; (2) settlement estimate using elastic theory (immediate settlement) and/or consolidation settlement (Terzaghi 1D consolidation equation) for a compressible clay layer if present. Show all calculations with cited equations, parameter values, and sources.

Proof required

Submit your calculations: bearing capacity calculation with equation, parameters (cohesion, friction angle, unit weight, foundation geometry, safety factor), and final bearing capacity result; and settlement estimate with equation, parameters (Young's modulus or Cc/Cs/e0, layer thickness, stress increment), and final settlement prediction in mm.

What gets checked

  • Bearing capacity calculation shows the equation, all parameter values with units, and the source of each parameter
  • Settlement calculation uses consolidation or elastic theory — not assumed as 'acceptable'
  • Safety factor or design approach is stated explicitly — not implied

Common mistakes

  • Bearing capacity calculation using parameters from memory without citing the source — every soil parameter (cohesion, friction angle) must trace to the site investigation data from M1 or a cited correlation
  • Omitting settlement calculation because the soil is strong — even strong soils settle under load; the calculation is required to confirm settlement is acceptable, not just assumed to be

Resources

Foundationstart here

Depthgo deeper

What a verifier looks for

  • Confirm bearing capacity equation is stated explicitly with all parameters cited from site data or named correlations.
  • Confirm settlement calculation uses a named theory (elastic or consolidation) — not assumed acceptable.
  • Confirm safety factor or design approach is stated and justified.

Write the Geotechnical Assessment Report

2–3 weeks (2–3 hrs/week)

Write a complete geotechnical assessment report (2,000–3,000 words plus figures and calculations appendix) covering: site description, investigation data summary, soil classification, bearing capacity calculation, settlement prediction, foundation type recommendation (shallow strip/pad/raft or deep piled foundation with justification), geotechnical risks (slope stability, liquefaction potential, swelling clay, groundwater, contamination), and limitations of the assessment. Have the report reviewed by a geotechnical engineer or structural engineer and answer Q&A on the foundation recommendation and risk assessment.

Proof required

Submit your geotechnical assessment report (2,000–3,000 words plus figures and calculations appendix) and review record: reviewer name, role, ≥3 challenge questions about the foundation recommendation or risk assessment, and your responses.

What gets checked

  • Foundation recommendation is justified by the bearing capacity and settlement calculations — not chosen by intuition
  • Geotechnical risks section addresses ≥3 site-specific risks relevant to the investigated soil profile and site conditions
  • Reviewer has geotechnical or structural engineering experience and challenged the foundation recommendation or risk identification specifically

Common mistakes

  • Foundation recommendation without a cost or performance argument for the selected type over alternatives — 'use a pad foundation' without explaining why raft or piles were rejected is incomplete
  • A geotechnical risks section that lists generic ground risks without relating them to the specific soil profile investigated — risks must be site-specific

Resources

Foundationstart here

What a verifier looks for

  • Engineering Design Triad check: M1–M3 together produce a design artifact (foundation recommendation + site profile), an analysis artifact (bearing capacity and settlement calculations), and a documentation artifact (geotechnical assessment report + review record) — confirm all three types are present.
  • Confirm foundation recommendation is justified by the calculation results — flag if chosen without reference to bearing capacity or settlement.
  • Confirm geotechnical risks are site-specific — flag generic lists not tied to the investigated soil profile.
  • Confirm reviewer has geotechnical or structural engineering experience and challenged the recommendation specifically.
  • The Proof Accessibility Rule applies — BGS open borehole records (free), MIT OCW (free), CIRIA free publications, GeoEngineer.org free tools, and USGS free data are all accessible without commercial licence.

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