The purpose of foundation treatment is to: improve the strength of soft foundations and ensure foundation stability; reduce the compressibility of soft foundations and decrease foundation settlement; prevent vibration liquefaction of foundation soil during earthquakes; eliminate the collapsibility, swelling-shrinkage, and frost heave of special soils. There are many methods for foundation reinforcement, which can be summarized as seven characters: "dig, fill, replace, tamp, press, squeeze, mix".

Interpretation of Foundation Reinforcement Methods

Dig

This means digging out the soft soil layer and embedding the foundation in bedrock or hard soil layer with high bearing capacity. When the soft soil layer is not thick, using the hard soil layer as a natural foundation is very economical.

Fill

When the soft soil layer is very thick and large-area foundation reinforcement is required, a certain thickness of good soil can be directly backfilled on top of the soft soil layer to improve the bearing capacity of the foundation and reduce the pressure on the soft soil layer.

Replace

Replace is the combination of digging and filling. It involves digging out the soft soil within a certain range below the foundation and replacing it with an artificially filled cushion as the bearing layer. This method is suitable for thick soft soil layers where only local foundation reinforcement is needed.

Tamp

Use tamping tools or machines to compact the soil, expel water from the soil, accelerate soil consolidation, and improve soil density and bearing capacity.

Press

Use compaction machinery to roll and compact the foundation soil, causing the foundation to consolidate through compaction and drainage. Preloading consolidation method can also be used, which involves stacking heavy objects on the ground within the foundation area for a period of preloading to compact the foundation, thereby improving bearing capacity and reducing settlement. This is called the preloading-drainage consolidation method.

Squeeze

Use a tool-type pile pipe with a pile shoe to drive into the soil, squeezing the soil to form a pile hole, then withdraw the pile pipe and fill the hole with sand, gravel, lime, plain soil, lime-soil, or other fill materials, and compact them. The principle is to densify the soil, drain and consolidate, and improve the foundation's bearing capacity. Commonly known as "compaction piles", including crushed (sand) stone piles, lime piles, lime-soil piles, CFG piles, etc.

Mix

This refers to reinforcing the foundation using jet grouting or deep mixing methods. The principle is to use high-pressure jets to cut the soil, spray grout (cement slurry, water glass, acrylamide, etc.), and mix the grout with the soil, causing the slurry and soil to mix and solidify into hard columns or soil walls.