Answer the following 5 questions on the following: a client informs you that a soil has a strong structure, slickensides and a high PI.

Question

The dominant clay mineral is:
a) Kaolinite
b) Montmorillonite
c) Goethite
d) Hematite
e) Lepidocrocite
f) All of the above
g) None of the above
10. The strong structure is an indication of:
a) Aerated conditions
b) saturated conditions
c) physical stability
d) physical instability
e) all of the above
f) none of the above
11. Water
a) high in the wet and low in dry state
b) high in the dry and low in the wet state
c) high in the wet and dry state
d) low in the wet and dry state
e) all of the above
f) none of the above
12. Root development in the soil will be:
a) restricted by the slickensides
b) restricted by the lack of structure
c) not restricted
d) all of the above
e) none of the above
13. Kaolinite clay is:
a) physically active and chemically active
infiltration in the soil would be:

b) physically active and chemically inactive
c) physically inactive and chemically active
d) physically inactive and chemically inactive
e) all of the above
f) none of the above

Answer 1

Here are the answers to the questions based on the given soil characteristics:

9. The dominant clay mineral is:

• b) Montmorillonite
  • Montmorillonite is known for having a high plasticity index (PI) and can exhibit slickensides due to its expansive nature when wet. Strong structural characteristics are also associated with this mineral.

10. The strong structure is an indication of:

• c) physical stability
  • A strong soil structure indicates that the soil has good aggregation and stability, which promotes aeration, but the use of "strong structure" typically refers to physical stability rather than the conditions of saturation or aeration.

11. Water:

• a) high in the wet and low in dry state
  • Generally, water content is high when the soil is wet, and lower when it is dry, especially relevant in soils with high plasticity.

12. Root development in the soil will be:

• a) restricted by the slickensides
  • Slickensides can create a hard, compact surface that makes it difficult for roots to penetrate, thus restricting root development.

13. Kaolinite clay is:

• b) physically active and chemically inactive
  • Kaolinite is relatively stable and does not expand or contract significantly with moisture changes (physically inactive), but it has limited cation exchange capacity, meaning it is chemically less active compared to smectites like montmorillonite.

These answers are based on the typical properties of these materials and soil behavior.