2.5. Settlement

Try these first

1. 1.

   What is the primary purpose of adding admixtures to soil?

   Hint

   Think about what construction needs.

2. 2.

   How does compaction affect voids in soil?

   Hint

   Compaction means squeezing the soil.

3. 3.

   What is the primary effect of adding stabilizing agents to soil?

   • Increase permeability
   • Stabilize soil
   • Decrease density

   Hint

   Think about why we use admixtures.

4. 4.

   True or False: Compaction increases the void ratio of soil.

   • True
   • False

   Hint

   Remember what happens during compaction.

5. 5.

   Calculate the desired compaction level needed to achieve optimal density in a sandy soil given an existing density of 1.6 g/cm³ and a target of 1.8 g/cm³.

   Hint

   Consider the relationship between density and the amount of compaction effort needed.

6. 6.

   Discuss the implications of choosing soil compacted wet of optimum versus dry of optimum on a construction project.

   Hint

   Reflect on balance between immediate stability and long-term settlement.