Groundworks Wet Soil Mixing Knowledge Quiz

1.

Wet soil mixing has been used to:

Increase bearing capacity

Decrease settlement

Increase global stability

Mitigate liquefaction potential

Support excavation

Stabilize ground for tunnel construction

All the above

Wet soil mixing creates columns of improved ground using the in-situ soil as the "aggregate" and the grout as the binding agent. The final strength of the column depends on both the existing soil and the amount of grout slurry injected. Analysis of the geometry of the column or composite mass with the improved strength will determine what capacity is available in compression or shear. In certain cases such as excavation support, reinforcement can be added to the columns for bending moment resistance.

Explanation

Wet soil mixing creates columns of improved ground using the in-situ soil as the "aggregate" and the grout as the binding agent. The final strength of the column depends on both the existing soil and the amount of grout slurry injected. Analysis of the geometry of the column or composite mass with the improved strength will determine what capacity is available in compression or shear. In certain cases such as excavation support, reinforcement can be added to the columns for bending moment resistance.

2.

Wet soil mixing is only effective in soils with high water content.

True

False

"Wet" soil mixing actually refers to the property of the binder slurry being mixed into the soil. That is, "wet" refers to the grout, not the soil. Wet soil mixing is best suited for maximum moisture contents of about 60%.

Explanation

"Wet" soil mixing actually refers to the property of the binder slurry being mixed into the soil. That is, "wet" refers to the grout, not the soil. Wet soil mixing is best suited for maximum moisture contents of about 60%.

3.

Wet soil mixing creates columns of pure grout with compressive strengths greater than concrete.

True

False

Wet soil mixing creates columns that are a mixture of the existing soil and the introduced grout. Therefore the ultimate strength of the soilcrete will be controlled by the type of soil and the amount of grout introduced. Achievable compressive strengths are on the order of 200 psi for silts and clays; and in excess of 1000 psi for clean sands.

Explanation

Wet soil mixing creates columns that are a mixture of the existing soil and the introduced grout. Therefore the ultimate strength of the soilcrete will be controlled by the type of soil and the amount of grout introduced. Achievable compressive strengths are on the order of 200 psi for silts and clays; and in excess of 1000 psi for clean sands.

4. What treatment geometries can wet soil mixing provide?

Single circular columns

Multiple column groups

Deep,long,linear homogeneous profile walls

Large shallow blocks

All the above

Single Axis Mixing Mass Mixing Method TRD - deep trench mixer

Explanation

Single Axis Mixing Mass Mixing Method TRD - deep trench mixer

5. The cost of wet soil mixing is generally _______ jet grouting.

More than

Less than

The same as

Wet soil mixing is roughly 1/3 the cost of jet grouting. Therefore it is beneficial to consider soil mixing first if project logistics permit and the desired results can be achieved.

Explanation

Wet soil mixing is roughly 1/3 the cost of jet grouting. Therefore it is beneficial to consider soil mixing first if project logistics permit and the desired results can be achieved.