In: Civil Engineering
Q4. A rigid strip footing is constructed on a
layered soil deposit, as shown in the...
Q4. A rigid strip footing is constructed on a
layered soil deposit, as shown in the figure.
Before construction of the footing, laboratory tests on a
saturated clay sample, taken at a depth of 6 m below the ground
surface, gave the following results:
- Compression index: Cc = 0.3,
- Recompression index: Cr = 0.08
- Over consolidation ratio: OCR = 1.5
- Water content: w = 25%
- Specific gravity: Gs = 2.65
Saturated unit weight of clay: gsat = 19.5
kN/m3
- Calculate the settlement of the footing due to deformation of
the sand layer only. Sand properties are as
follows:
- Total unit weight: gt = 18 kN/m3
- Young’s modulus: Es = 30
MPa
- Poisson’s ratio: n = 0.25
- Based on the elastic theory (Boussinesq’s equation), calculate
the change in vertical stress at point A long time after applying
the surcharge load.
- Using the theory of 1-D consolidation, calculate the total
settlement of this rigid footing due to consolidation of the clay
layer only, long time after applying the total load.