Rigid inclusions improve weak underlying stratum by transferring loads to a firmer stratum with the use of grouted or concrete elements.
- Improve bearing capacity
- Reduce settlement
The grouted or concrete elements are high modulus, controlled stiffness columns. They are typically installed using a bottom-feed mandrel equipped with a vibrator that is pushed through the weak strata to get to the firmer strata. Concrete or grout is pumped through the mandrel as it is being removed from the ground and fills the void. Other methods of installation can be used for the installation of rigid inclusions such as displacement drilling techniques or continuous flight augers.
The mandrel can construct a more expanded base, if the design requires it, by being raised and lowered multiple times at the bearing depth. When removed, a reinforced upper stratum is created which is typically overlain by a granular load transfer platform (LTP).