Chartered Civil Engineer (ICE) Geotechnical and Foundation Engineering Syllabus

Geotechnical and Foundation Engineering syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Geotechnical and Foundation Engineering in Chartered Civil Engineer (ICE), not a summary of it.

1. 1

   Soil Mechanics

   5 topics

   • Soil classification and phase relationships
   • Effective stress principle and pore pressure
   • Permeability and seepage
     • Darcy's law and flow nets
     • Critical hydraulic gradient and piping
   • Consolidation and settlement
     • Terzaghi one-dimensional consolidation
     • Primary and secondary settlement
   • Shear strength of soils
     • Drained and undrained behaviour
     • Mohr-Coulomb failure criterion
2. 2

   Site Investigation and Ground Characterisation

   5 topics

   • Desk study and walkover survey
   • Intrusive investigation methods
     • Boreholes, trial pits and sampling
     • In-situ testing (SPT, CPT, vane)
   • Laboratory testing programmes
   • Geotechnical reporting to Eurocode 7
     • Ground Investigation Report and Geotechnical Design Report
   • Contaminated land assessment
3. 3

   Foundation and Retaining Structure Design

   6 topics

   • Shallow foundation bearing capacity and settlement
   • Deep foundations
     • Pile types and installation methods
     • Axial and lateral pile capacity
     • Pile groups and negative skin friction
   • Earth pressure theory (active, passive, at-rest)
   • Retaining wall design
     • Gravity, cantilever and embedded walls
     • Anchored and propped walls
   • Slope stability analysis
   • Ground improvement and earthworks

Geotechnical and Foundation Engineering flashcards for Chartered Civil Engineer (ICE)

23 of 60 cards from the Geotechnical and Foundation Engineering deck — real questions with worked answers.

1. In the Unified Soil Classification System (USCS) / BS classification, what do the symbols G, S, M, C and the qualifiers W, P, L, H denote?

   G = gravel, S = sand, M = silt, C = clay (also O = organic, Pt = peat). Secondary letters: W = well-graded, P = poorly-graded, L = low plasticity (liquid limit $<50\%$), H = high plasticity (liquid limit $>50\%$). E.g. SW = well-graded sand, CH = high-plasticity clay.

2. Define the three-phase soil system and write the phase relationship linking void ratio $e$, degree of saturation $S_r$, water content $w$ and specific gravity $G_s$.

   Soil consists of solids, water and air. The fundamental identity is $$S_r \, e = w \, G_s.$$ For a fully saturated soil $S_r = 1$, so $e = w \, G_s$.

3. Write the formulas for void ratio $e$, porosity $n$ and the relationship between them.

   $$e = \frac{V_v}{V_s}, \qquad n = \frac{V_v}{V}, \qquad n = \frac{e}{1+e}, \qquad e = \frac{n}{1-n}.$$ $V_v$ = volume of voids, $V_s$ = volume of solids, $V$ = total volume.

4. Give the expressions for bulk (total) unit weight $\gamma$, dry unit weight $\gamma_d$ and saturated unit weight $\gamma_{sat}$ in terms of $G_s$, $e$ and $\gamma_w$.

   $$\gamma = \frac{(G_s + S_r e)\,\gamma_w}{1+e}, \quad \gamma_d = \frac{G_s \gamma_w}{1+e}, \quad \gamma_{sat} = \frac{(G_s + e)\,\gamma_w}{1+e}.$$ Also $\gamma_d = \dfrac{\gamma}{1+w}$, with $\gamma_w \approx 9.81\ \mathrm{kN/m^3}$.

5. Define the Atterberg limits and the plasticity index, and state the formula for liquidity index.

   Liquid limit $w_L$ (LL) = water content at plastic–liquid boundary; plastic limit $w_P$ (PL) = water content at semi-solid–plastic boundary; shrinkage limit = below which no further volume reduction. Plasticity index $I_p = w_L - w_P$. Liquidity index $$I_L = \frac{w - w_P}{w_L - w_P}.$$

6. State Terzaghi's principle of effective stress and write the governing equation.

   All measurable effects of a change of stress (compression, distortion, change of shear strength) are due solely to changes in effective stress. $$\sigma' = \sigma - u,$$ where $\sigma$ = total normal stress, $u$ = pore water pressure and $\sigma'$ = effective stress carried by the soil skeleton.

7. How is hydrostatic pore water pressure calculated, and how do you obtain vertical effective stress at depth $z$ below a water table at the surface?

   Pore pressure $u = \gamma_w z_w$ (with $z_w$ = depth below the water table). Vertical total stress $\sigma_v = \gamma_{sat} z$; vertical effective stress $$\sigma'_v = \sigma_v - u = (\gamma_{sat} - \gamma_w)\,z = \gamma' z,$$ where $\gamma'$ is the submerged (buoyant) unit weight.

8. What is the effect of a rising or falling water table, and of upward seepage, on effective stress?

   A rising water table increases pore pressure and reduces effective stress; a falling water table increases effective stress (can cause settlement). Upward seepage reduces effective stress; when the upward seepage force balances $\gamma'$, effective stress falls to zero and quick/boiling conditions occur.

9. State Darcy's law for flow through soil and define the terms.

   $$v = k\,i, \qquad Q = k\,i\,A = v A,$$ where $v$ = discharge (superficial) velocity, $k$ = coefficient of permeability (m/s), $i = \dfrac{\Delta h}{L}$ = hydraulic gradient, $A$ = cross-sectional area, $Q$ = flow rate. Valid for laminar flow.

10. Give the critical hydraulic gradient for quicksand / piping and a typical value.

    Critical (upward) hydraulic gradient: $$i_c = \frac{\gamma'}{\gamma_w} = \frac{G_s - 1}{1 + e}.$$ For typical soils $i_c \approx 1.0$. Quick conditions occur when $i \geq i_c$.

11. For a flow net, how is seepage quantity calculated and what do $N_f$ and $N_d$ represent?

    $$Q = k\,h\,\frac{N_f}{N_d},$$ where $h$ = total head loss across the net, $N_f$ = number of flow channels (paths), $N_d$ = number of equipotential drops. Flow lines and equipotentials intersect at right angles forming curvilinear squares.

12. How do permeability values typically vary between gravel, sand, silt and clay?

    Approximate $k$ ranges: gravel $>10^{-1}\ \mathrm{m/s}$; clean sand $10^{-2}$–$10^{-5}\ \mathrm{m/s}$; silt $10^{-5}$–$10^{-8}\ \mathrm{m/s}$; clay $<10^{-8}\ \mathrm{m/s}$ (effectively impermeable). Permeability spans roughly ten orders of magnitude across soil types.

13. Distinguish constant-head and falling-head permeability tests and state which soils each suits.

    Constant-head test: maintains a fixed head difference; measures volume over time, $k = \dfrac{QL}{hA t}$. Best for coarse, permeable soils (sands/gravels). Falling-head test: water level in a standpipe falls; $k = \dfrac{aL}{A t}\ln\dfrac{h_1}{h_2}$. Best for fine-grained low-permeability soils (silts/clays).

14. State Terzaghi's one-dimensional consolidation equation and define the coefficient of consolidation.

    $$\frac{\partial u}{\partial t} = c_v \frac{\partial^2 u}{\partial z^2}, \qquad c_v = \frac{k}{m_v \gamma_w},$$ where $c_v$ = coefficient of consolidation, $k$ = permeability, $m_v$ = coefficient of volume compressibility, $\gamma_w$ = unit weight of water.

15. Give the formula for primary consolidation settlement of a normally consolidated clay using the compression index $C_c$.

    $$s_c = \frac{C_c \, H_0}{1+e_0} \log_{10}\!\left(\frac{\sigma'_0 + \Delta\sigma'}{\sigma'_0}\right),$$ where $C_c$ = compression index (slope of $e$–$\log\sigma'$ line), $H_0$ = layer thickness, $e_0$ = initial void ratio, $\sigma'_0$ = initial effective stress, $\Delta\sigma'$ = stress increase.

16. Define the degree of consolidation $U$ and time factor $T_v$, and give the drainage path relationship.

    $U$ = proportion of consolidation settlement completed at time $t$. Time factor $$T_v = \frac{c_v t}{d^2},$$ where $d$ = length of the longest drainage path ($d = H$ for single drainage, $d = H/2$ for double drainage). Approx: $T_v \approx \frac{\pi}{4}U^2$ for $U \le 60\%$.

17. Distinguish normally consolidated (NC) and overconsolidated (OC) clay, and define the overconsolidation ratio.

    NC clay: present effective stress equals the maximum it has ever experienced. OC clay: has previously been subjected to a higher stress (preconsolidation pressure $\sigma'_c$). $$OCR = \frac{\sigma'_c}{\sigma'_0}.$$ OCR = 1 for NC; OCR > 1 for OC. OC clays are stiffer and use the recompression index $C_r$.

18. State the Mohr–Coulomb failure criterion for soil shear strength in terms of effective stress.

    $$\tau_f = c' + \sigma'_n \tan\phi',$$ where $\tau_f$ = shear strength on the failure plane, $c'$ = effective cohesion intercept, $\sigma'_n$ = effective normal stress on the plane, $\phi'$ = effective angle of shearing resistance (friction angle).

19. Differentiate drained and undrained shear strength, and give the undrained strength criterion ($\phi_u = 0$).

    Drained: pore pressures dissipate, analysis uses effective parameters $c', \phi'$ (long-term). Undrained: no drainage during loading, total-stress analysis with $\tau_f = c_u$ and $\phi_u = 0$ (short-term, clays). $c_u$ = undrained shear strength = half the deviator stress at failure in a UU triaxial test.

20. Name the main laboratory tests for measuring soil shear strength and what each provides.

    Direct shear (shear box): gives $c'$, $\phi'$ at chosen normal stresses. Triaxial test (UU, CU, CD): controlled drainage/pore pressure; gives $c_u$ or $c', \phi'$. Vane shear: undrained strength $c_u$ of soft clays (lab or in situ). Unconfined compression: rapid $c_u = q_u/2$ for cohesive soils.

21. What is the relationship between the principal effective stresses at failure (Mohr-Coulomb) for a $c'$, $\phi'$ soil?

    $$\sigma'_1 = \sigma'_3 \tan^2\!\left(45^\circ + \tfrac{\phi'}{2}\right) + 2c' \tan\!\left(45^\circ + \tfrac{\phi'}{2}\right).$$ The failure plane is inclined at $\theta = 45^\circ + \frac{\phi'}{2}$ to the major principal plane.

22. What is the purpose of a desk study in a ground investigation, and name typical information sources?

    A desk study collects existing information to identify ground conditions, hazards, history and constraints before fieldwork, informing the conceptual ground model and investigation scope. Sources: geological maps/memoirs (BGS), historical OS maps, aerial photos, mining records, previous site investigation reports, groundwater/flood data, Envirocheck/contamination records, utility records.

23. What is a walkover survey and what features does the engineer look for?

    A walkover (site reconnaissance) is a physical inspection of the site to corroborate and supplement the desk study. The engineer notes topography, surface water/springs, vegetation, made ground/fill, existing structures and cracking, slope instability signs, access constraints, nearby structures, evidence of contamination, and disposal/odour indicators.

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