Compressibility and Consolidation

Select the CORRECT soil layer for this statement;

A 4 m clay layer underlaid by the 2 m sand layer. The groundwater table is at the surface of the clay layer.

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The clay layer is a compressible soil. It has a double drainage condition.

• TRUE

• FALSE

Calculate the current overburden stress at mid of clay layer, σo. If the pre-consolidation of clay soil, σc is 100 kN/m2, the clay soil condition is normally consolidated soil.

• TRUE

• FALSE

Step by step to analyze the settlement of soil is as follows:

I. Define soil type (i.e Normally consolidated or Over Consolidated)

II. Define laboratory test of Pc, Cc, Cr, Cv (from soil sample of field site)

III. Calculate current overburden

IV. Calculate the surchage

V. Decide the equation of settlement and obtain the settlement.

• I, II, III, IV, V

• II, III, IV, I, V

• III, IV, V, I, II

• V, IV, III, II, I

In consolidation, soil that experience consolidation will allow water to dissipate out and producing a settlement.

• TRUE

• FALSE

Define for the equation of settlement if we want to obtain settlement for the mid clay layer. The soil profile also have an external loading from embankment (assume to be wide enough) with Q of 20 kN/m2 laid at the ground surface. Given the effective pre-consolidation pressure is 80 kN/m2. Assume the unit weight of water is 10 kN/m3.

• Normally consolidated

• Over consolidated soil with Cc parameter only

• Over consolidated soil with Cc and Cr parameter