Which of the following is true about tremie piping?

• A. It introduces air pockets during grouting
• B. It is used to grout from the bottom of the hole without air pockets
• C. It is used for drilling boreholes
• D. It seals the borehole after installation

Answer: (B)

Tremie piping is a method for placing grout from the bottom of a borehole or trench so that the grout fills voids from the lowest point upward without trapping air. The tremie tube stays submerged in the grout and is lowered to the bottom; grout is pumped through the tube, pushing water and any air ahead of it and forming a continuous grout column as you raise the tube. This bottom-up placement prevents air pockets and segregation that can occur if grout is introduced from the top, especially in wet or groundwater conditions. It’s specifically a grout placement technique, not a drilling method, and it’s not used to seal a borehole after installation.