Stage 6 engineering analyses

Stage 6 analyses on the interpreted section.

This section documents the engineering modules that sit on top of the interpreted CPT layer model. Each page explains analysis class, governing formulation, user inputs, output meaning, and implementation boundaries.

Scope

Stage 6 scope

Stage 6 of the application flow: slope stability, seepage, deformation, settlement screening, and related design checks.

This chapter is organized by analysis family. Each route documents one engineering formulation, its governing equations, required inputs, reported outputs, and boundaries of validity. The chapters are equally first-class deliverables; the grouping below is by physical question, not by implementation cost.

Analysis families

Implemented analysis families

foundation design → CPT-direct resistance + EC7 / Belgian ANB factors
slope stability → limit equilibrium on slices
groundwater → analytical drawdown screen and steady-state FE Darcy flow
deformation → small-strain plane-strain FE equilibrium
  • Foundation design covers the shallow- and deep-foundation routes (bearing, pile, settlement, beam / slab on elastic foundation, EC2 reinforcement) under EC7 with the Belgian National Annex and DM20 / ATG pile factors.
  • Slope stability uses Bishop simplified for the search and a full Spencer recheck on shortlisted circles.
  • Groundwater covers analytical radius-of-influence drawdown screening and a steady-state FE Darcy solver with free-surface iteration.
  • Deformation is a plane-strain FE solver with geostatic initialization and exact Mohr-Coulomb elastoplasticity with tension cut-off.

Foundation design

Foundation analyses

Shallow foundations · ULS

Bearing capacity

Brinch Hansen / EC7 Annex D factor chain, drained and undrained envelopes, effective dimensions, water-table averaging, and Belgian DA1 handling.
Deep foundations · ULS & SLS

Pile capacity

Axial pile resistance and SLS settlement: De Beer scale-effect base resistance, Belgian shaft-friction table, full ULS factor chain (γRd, ξ3 / ξ4, γb, γs), Fnk screening, and load-transfer settlement.
Shallow foundations · SLS

Settlement

Stress-increase integration, constrained-modulus settlement, truncation rules, and optional time-dependent interpretation.
Structural–geotechnical strip

Beam / slab on elastic foundation

ks derivation from the CPT stiffness profile, Winkler and Pasternak strip equations, and the present screening route.
EC2 ULS output

ULS reinforcement output

Strip-based EC2 reinforcement screening from the design moment, material factors, and cover assumptions.

Slope stability

Slope-stability analysis

Limit equilibrium · circular

Bishop + Spencer

Circular slip-surface search, slice equilibrium, Spencer verification, and references for the Stage 6 slope-stability route.

Groundwater

Groundwater analyses

Steady-state FE Darcy flow

Seepage analysis

Steady-state Darcy flow, boundary-condition semantics, free-surface iteration, and coupled pore-pressure interpretation.
Analytical drawdown screen

Dewatering

Radius-of-influence screening, layered transmissivity, drawdown profiles, and drawdown-induced effective-stress effects.

Deformation

Deformation analysis

Plane-strain FE equilibrium

Deformation analysis

Geostatic initialization, exact Mohr-Coulomb elastoplasticity with tension cut-off, plotted fields, and solver interpretation.

Reading sequence

Recommended reading sequence

  • CPT interpretation precedes any audit of Stage 6 parameters and soil-property origin.
  • Methods and assumptions should be consulted before detailed review of the module-specific equations.
  • Individual engineering chapters may be consulted directly when the analysis class is already known.
  • Standards and references and the technical specification provide bibliographic traceability and the full equation-by-equation audit trail.