FE_GEOTECH_PART2_AJ PROFESSIONAL SERVICES

Which of the following statements are true about soil shear strength?

Select the three that apply.

• ☐ The presence of cohesion will increase the shear strength.

• ☐ At failure, the applied shear stress equals the shear strength of the soil.

• ☐ As the friction angle decreases, shear strength increases.

• ☐ As the cohesion decreases, shear strength increases.

• ☐ Some soils have shear strength even when the effective stress is zero.

A soil incurs slip failure when it is subjected to a shear stress of 50 kPa along the slip surface. The cohesion of the soil is 20 kPa with an internal friction angle of 35°. Based on the Mohr coulomb failure criteria, the normal stress (kPa) on the failure slip plane is most nearly:

• 25.5

• 35.5

• 42.8

• 40.4

Two direct shear tests were conducted on sandy soil. The normal and shear stress data at failure was recorded as shown by the table below. Based on graphed the failure envelope below, the internal friction angle is most nearly:

• 8.7°

• 26.6°

• 63.4°

• 25.3°

The footing shown has a groundwater level that’s at the ground surface. When determining the ultimate bearing capacity, the unit weight (lb/ft3) value is most nearly:

• 57.6

• 116

• 120

• 98.3

A continuous strip footing that’s 4 ft wide and 1 ft thick rests on a soil at a depth of 5 ft below the ground surface. The soil has a cohesion value of 75 psf, and the unit weight of the soil is 120 pcf. For a friction angle of 30∘, the bearing capacity factors are as follows:

The ultimate bearing capacity (psf) for the soil is most nearly:

• 28,709

• 33,168

• 27,245

• 33,020

The strip footing shown has an allowable bearing capacity of 6,350 lb/ft2 and a factor of safety of 2.0. The width (ft) of the strip footing is most nearly:

• 3 ft

• 3.5 ft

• 4 ft

• 4.5 ft

Using the given soil properties around the strip footing shown, the ultimate bearing capacity (kips/ft2) is most nearly:

• 8.1

• 9.2

• 12.7

• 16.9

Based on the Terzaghi’s bearing capacity theory, a shallow foundation is usually defined as a foundation which has:

• (A) Depth greater than its width

• (B) Depth less than its width

• (C) Depth six times its width

• (D) Depth two times its width

A building is planned that will use shallow foundations to support load bearing wall loads. What type of foundation is used to carry the wall loads:

• (A) Isolated Footing

• (B) Strip Footing

• (C) Combined Footing

• (D) Mat Foundation

A building is planned that will use shallow foundations to support wall loads. What type of foundation will likely be used to support the outside column loads if the columns are spaced close to each other:

• (A) Isolated Footing

• (B) Strip Footing

• (C) Combined Footing

• (D) Mat Foundation