FOUNDATION ENGINEERING - Midterm Exam 6. A sheet pile is shown in the figure. 8. A square footing with dimension of 1.3 x 1.
3
a. Determine the minimum value of embedment m has its bottom 1.5 m below the ground
1. A direct shear test is performed on a depth d for stability, in meters. (Ans: 4.347m) surface. The groundwater table is expected to
specimen of dry sand. The shear box is circular in b. Using the minimum value of d, determine the exist during the life of the structure. The unit
cross-section with a diameter of 50 mm. The Soil 1:
H1 tension in the tie rod per meter length of pile. weight of soil above the water table is 17.20
γ1, φ1
normal force imposed on the specimen is 250 N. (Ans: T = 171.77 kN) kN/m3 and that below the water table is 19.60
The shear force is 150 N. Determine the angle of kN/m3. The angle of internal friction is 20° and
internal friction of this sand. (Answer: φ=30.96°) γm = 19.62 kN/m3 cohesion is 15 kPa. Using general shear failure
Ka = 0.3
and a factor of safety of 3.0. For angle of internal
2. A triaxial test on a saturated soil has the Soil 2: friction of 20°, the bearing capacity factor are Nc
γ2, φ2 H2
following results: = 17.69; Nq=7.44; Nγ=3.64.
Cell Pressure Deviator Pore Pressure a. Calculate the gross allowable bearing capacity
(kPa) Stress (kPa) (kPa) if the water table is 4 m below the ground
200 119 142.5 surface. (Ans: 189.821 kPa)
400 143 275.5 a. Determine the total lateral pressure at the Ka = 0.3 b. Calculate the gross allowable bearing capacity
γsat = 19.49 if the water table is 2 m from the ground surface.
600 178 396 base of the wall. (Ans: 88.25 kPa) kN/m3
a. Determine the drained angle of internal b. Determine the total active force acting on the (Ans: 186.944 kPa)
friction of the soil. (Ans: φ=8.737°) wall. (Ans: 331.61 kN) c. Calculate the gross allowable bearing capacity
b. Determine the cohesion of the soil in drained c. Determine the total active moment acting on if the water table is at the embedment of the
condition. (Ans: 42.22 kPa) the wall. (Ans: 884.85 kN-m) Kp = 3
foundation. (Ans: 185.146 kPa)
γsat = 19.49 d. Calculate the gross allowable bearing capacity
kN/m3
3. The results of a consolidated-drained triaxial 5. A retaining wall is shown in the figure. if the water table is 1.0 m from the ground
test conducted on a normally consolidated clay, a. Determine the total active pressure before surface. (Ans: 175.957 kPa)
are as follows: tensile crack occurs. (Ans: 76 kN)
Chamber confining 250 kPa b. Determine the total active pressure after
stress, σ3 tensile crack occurs. (Ans: 79.45 kN) 7. A square foundation is shown in the figure.
Deviator stress at 350 kPa The footing will carry a gross mass of 30,000 kg.
q = 15 kN/m2
failure Using a factor of safety of 3, determine the size
a. Calculate the angle of friction of the soil of the footing - that is the size of B. Assume
sample. (Ans: φ=24.316°) general shear failure. For φ=35°, Nc=57.75,
b. Calculate the shear stress on the failure plane. Nq=41.44 and Nγ=45.51.
(Ans: τ = 159.5 kPa)
c. Calculate the effective normal stress on the
plane of maximum shear. (Ans: σ = 425 kPa) γ = 16.5 kN/m3 “Wala dito si Chito.
φ = 26° Wala din si Kiko.
H = 6m c = 10 kN/m2
4. From the figure shown: Surcharge load is Wala din si Cloc 9.
applied at the ground surface qo = 40 kPa. Pero…
H1 = 3m, ɣ1 = 17 kN/m3, φ1 = 22° May MAGBABAGSAKAN DITO.”
H2 = 4m, ɣ2 = 21 kN/m3, φ2 = 28°
