Foundation Engineering

Daffodil International University B.Sc. in Civil Engineering Final Examination, Summer - 2026 Course Code: CE 333 Course Title: Foundation Engineering Section: A & B Level-Term: 3-2 Teacher's Initial: MLE Full Marks: 40 Date: August 22, 2026 Time: 2.0 Hours Note: There are four questions in total; answer all. Right hand margin indicates full marks. 1. a) An eccentrically loaded continuous foundation is shown in Figure 1.a. If the load eccentricity is 0.2 m, determine the net allowable load per unit length of the foundation with a safety factor of 3.0. Use Meyerhof's effective area method. [CO3, C3] [Figure: An eccentrically loaded continuous foundation showing width B=2.0 m, depth Df=1.5 m, load Q_a and moment M on a T-shaped footing resting on soil with phi'=40 degrees, c'=0, and unit weight gamma = 16.5 kN/m^3] b) Proportion the trapezoidal combined foundation as shown in Figure 1.b. Assume that the soil supporting the footing has a net allowable pressure of 120 kN/m^2. [CO3, C3] [Figure: A trapezoidal combined foundation plan and section showing lengths L1, L2, L3, widths B1, B2, column loads 400 kN and 1000 kN, and a 3 m spacing between columns] 2. a) It is proposed to construct an 8-story building on the soil profile shown in Figure 2.a. The building requires a basement and will be supported on a 15 m x 20 m mat foundation carrying a total load of 48,000 kN. The mat is to be designed as a partially compensated foundation. Determine the required foundation depth to satisfy the basement requirement while achieving a factor of safety of 3.0 against bearing capacity failure. [CO3, C3] b) Using the information from Question 2.a, estimate the primary consolidation settlement at the center of the same mat foundation. Is the computed settlement within the safe limit? [CO3, C3] [Figure: Soil profile showing 2.0 m of sand (phi'=29 degrees, c'=0, gamma = 16.5 kN/m^3), 6.0 m of normally consolidated clay (gamma_sat = 16.5 kN/m^3, c_u = 48 kN/m^2, e_0 = 1.0, C_c = 0.31), 3.0 m of normally consolidated clay (gamma_sat = 17.5 kN/m^3, c_u = 70 kN/m^2, e_0 = 0.97, C_c = 0.29), and a dense sand layer underneath] 3. a) Determine the group allowable load (Q_ga) with a safety factor of 2.5 for the concrete driven circular piles as shown in Figure 3.a. The diameter of each pile is D = 0.35 m and center-to-center (d) is 1.0 m. [CO3, C3] [Figure: Pile group cross section and layout showing pile dimensions, L_g, B_g, pile diameter D, spacing d, and soil properties of loose sand (gamma_sat = 17 kN/m^3, phi'=29 degrees) and dense sand (gamma_sat = 19 kN/m^3, phi'=42 degrees)] b) Determine the maximum load that can be allowed on the 450 mm diameter concrete driven pile shown in Figure 3.b, with a factor of safety of 3. Use the alpha method for determining the skin friction. [CO3, C3] [Figure: Single pile of diameter D = 0.45 m embedded in three clay layers of depths 5 m, 6 m, and 8 m with respective undrained cohesive strengths c_u = 40 kN/m^2, 60 kN/m^2, and 80 kN/m^2 and unit weights gamma = 18 kN/m^3, 18.5 kN/m^3, and 19 kN/m^3] 4. a) An embankment has to be constructed on an existing clay layer using uniform sand to a height of 6 m with a side slope of 1V:1.5H as shown in the Figure 4.a. A firm base underlies the embankment at a depth of 3 m below the ground surface. Analyze the stability of the side slope against failure. Use the attached graph and a scale of 1 grid equal to 0.2 m for drawing the slope. [CO5, C4] [Figure: Embankment cross section showing 6 m height, 1.5H:1V side slope, underlying sand layer (gamma = 18 kN/m^3, phi'=31 degrees, c_u = 0), clay layer (gamma = 17 kN/m^3, c_u = 50 kN/m^2, phi'=0) of 3 m thickness, and a firm base] b) Describe slurry construction method of bored pile. [CO4, C2]