CE-802-B Foundation Engineering - May 2026 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aExplain the different types of foundations with suitable sketches and their applications.
   How to answer

   • Define shallow vs deep foundations
   • List types: isolated, combined, strip, mat/raft, pile, pier, caisson
   • Sketches for each type
   • Applications based on load, soil, groundwater
2. 7 Marks
   bDuring a subsurface investigation for a proposed multi-storey building, Standard Penetration Tests (SPT) were conducted in a fine sand deposit at depths of 4 m, 8 m, 12 m, and 16 m below the ground surface. The observed SPT N-values at these depths were 12, 22, 30, and 38, respectively. The groundwater table is located at a depth of 2 m below the ground level. The bulk unit weight and saturated unit weight of the soil are $18 \text{ kN/m}^3$ and $20 \text{ kN/m}^3$, respectively. Determine the corrected SPT values at all depths by applying suitable overburden correction and dilatancy corrections, wherever necessary. Also comment on the variation in soil density with increase in depth.
   How to answer

   • Compute effective overburden stress at 4, 8, 12, 16 m
   • Apply overburden correction $N_c = 350/(\bar{\sigma}+70)$ or $C_N$
   • Apply dilatancy correction $N_{corrected}=15+(N_1-15)/2$ where $N_1>15$ below WT in fine sand
   • Comment on relative density increase with depth
3. 7 Marks
   aA Dynamic Cone Penetration Test (DCPT) was conducted in sandy soil using a 65 kg hammer falling through a height of 750 mm. The number of blows required for 300 mm penetration at different depths were found to be 12, 18, 25, and 40. Interpret the soil density at each depth and suggest a suitable type of foundation for the proposed structure.
   How to answer

   • State DCPT procedure: 65 kg hammer, 750 mm drop, blows per 300 mm
   • Correlate blows 12, 18, 25, 40 to loose to very dense
   • Interpret density increase with depth
   • Suggest shallow vs deep foundation based on strata
4. 7 Marks
   bA strip footing of width 2 m is founded at a depth of 1.5 m in sand having unit weight of $18 \text{kN/m}^3$ and angle of internal friction of $30^\circ$. Using Terzaghi's bearing capacity theory with $N_c=30.1$, $N_q=18.4$, and $N_{\gamma}=15.7$, determine the ultimate bearing capacity of the soil.
   How to answer

   • Write Terzaghi strip footing formula $q_u = cN_c + \gamma D_f N_q + 0.5\gamma B N_\gamma$
   • For sand $c=0$, substitute $\gamma=18$, $D_f=1.5$, $B=2$, $N_q=18.4$, $N_\gamma=15.7$
   • Compute $q_u$ in $kN/m^2$
5. 7 Marks
   aDescribe the different modes of shear failure in soils beneath shallow foundations with neat sketches.
   How to answer

   • Define general, local and punching shear failure
   • Draw load-settlement and failure surfaces for each
   • Compare characteristics: heave, settlement, density dependence
6. 7 Marks
   bA footing founded on sand experiences general shear failure. If the ultimate bearing capacity is $600 \text{ kN/m}^2$ and factor of safety is 3, determine the allowable bearing pressure and safe load for a footing area of $5 \text{ m}^2$.
   How to answer

   • Allowable pressure $q_a = q_u / F$
   • Substitute $q_u=600$, $F=3$
   • Safe load $Q = q_a \times A$ for $A=5 m^2$
7. 7 Marks
   aWhat is negative skin friction in pile? Explain its causes and effects.
   How to answer

   • Define negative skin friction / downdrag
   • List causes: fill, dewatering, consolidation, pile driving
   • Explain effects: extra load, increased settlement, reduced capacity
8. 7 Marks
   bA 400 mm diameter pile is driven into a clay soil with cohesion of $60 \text{ kN/m}^2$. The embedded length of pile is 18 m and adhesion factor is 0.7. Determine the ultimate load carrying capacity of the pile using static formula considering end bearing and skin friction.
   How to answer

   • End bearing $Q_b = 9c \times A_b$
   • Skin friction $Q_s = \alpha c \times \pi d L$
   • Sum $Q_u = Q_b+Q_s$ with $d=0.4 m$, $L=18 m$, $c=60$, $\alpha=0.7$
9. 7 Marks
   aA pile group consists of 12 pile of diameter 400 mm spaced at 1.2 m center to center in clay soil. If the efficiency of the group is 0.82 and single pile capacity is 500 kN, determine the safe load carrying capacity of the group.
   How to answer

   • Group capacity = efficiency x n x single pile capacity
   • Substitute n=12, eta=0.82, Q=500 kN
   • Result is ultimate group capacity; divide by FS if safe load required
10. 7 Marks
    bDiscuss the preventive measures adopted for construction on expansive and collapsible soils.
    How to answer

    • Define expansive and collapsible soils
    • Preventive measures: moisture control, replacement, compaction, piles/piers
    • Chemical stabilization, pre-wetting, CNS layer
11. 7 Marks
    aDesign an underreamed pile for a column load of 450 kN using allowable soil bearing capacity of $120 \text{ kN/m}^2$ and determine the required bulb diameter if the pile stem diameter is 0.4 m.
    How to answer

    • Required area = Load / allowable capacity
    • Equate to bulb area $\pi D^2/4$ minus stem
    • Solve for bulb diameter $D$ with stem 0.4 m
12. 7 Marks
    bExplain the different types of geosynthetic materials and discuss their engineering properties and applications.
    How to answer

    • List types: geotextiles, geogrids, geomembranes, geocells, geocomposites
    • Engineering properties: tensile, permeability, durability
    • Applications: separation, reinforcement, drainage, containment
13. 7 Marks
    aA retaining wall retains a layered backfill consisting of 3 m of sand with $\gamma = 16 \text{ kN/m}^3$, $\varphi = 28^\circ$ overlying 4 m of sand with $\gamma = 20 \text{ kN/m}^3$, $\varphi = 34^\circ$. Determine the total active earth pressure using Rankine's theory of earth pressure.
    How to answer

    • Compute $K_a = (1-\sin\phi)/(1+\sin\phi)$ for $\phi=28^\circ, 34^\circ$
    • Compute stresses at 0, 3 m and 7 m with surcharge from top layer
    • Total thrust = area of pressure diagram per metre
14. 7 Marks
    bDescribe the classification and functions of retaining walls and explain the design considerations for ensuring stability against overturning, sliding, and bearing capacity failure.
    How to answer

    • Classify: gravity, cantilever, counterfort, crib, anchored
    • Functions: retain soil, prevent erosion
    • Stability checks: overturning FS, sliding FS, bearing capacity
15. 14 Marks
    Write a short note on :

    1. a)Coulomb's earth pressure theory
    2. b)Static formula and dynamic formula
    3. c)Corrections for plate load test results
    How to answer

    • Coulomb theory: assumptions, wedge, friction, formula
    • Static vs dynamic pile formulas: Hiley, Engineering News
    • Plate load corrections: size, saturation, bending