Strengthening a two-story building with expanding geopolymer columns
- Category
- Private residential building
- Object
- Residential two-story building
- Focus
- Stop subsidence and strengthen the foundation
- Location
- Finland
- Time of work
- 2012 г.
- The timing
- 3 days
- TECHNOLOGY
- COLUMN INJECTION
SUMMARY
With the help of self-expanding geopolymer columns, the issue of strengthening the two-story building was solved.
PURPOSES
Construction of the two-story house began in winter. The underlying layers of the loamy soil were selected and replaced with two meters of gravel with a fraction size of up to 32 mm. Rubble foundations made of stone with a size of 100-250 mm. A gross mistake was to strengthen the foundation soil with construction debris at a depth of less than 2 meters from the level of the surface. Ice collected in the pores of the aggregate (construction debris), which caused future subsidence. With the onset of a warm period and an increase in the ambient temperature, the ice melted, which caused the facade of the building to subside with range of 4 to 30 mm. The uncompacted areas were located at a depth of 1.4-1.7 m.
APPLIED TECHNOLOGY
The chosen solution was the Deep Injection technology with column extantion. URETEK geopolymer was used as the base, in order to create a solid ground support and to transfer and evenly distribute loads from building structures. With the help of additional injection points of URETEK auxiliary compounds, the house was lifted with accuracy of 4 mm. After that, deep injections were performed on the damaged area to seal the base to a level of 0.5 m below the ground level. Further, geopolymer columns were installed under the supporting structures using continuous injections.
RESULT
After determining the problem zone at a depth of 1.4-1.7 m (during dynamic penetration test), it was found that the loose gravel, after melting the ice, became more dense, which created the problem of creating voids and cavities. These zones were injected with a geopolymer that has the properties of small expansion at very high density to create a solid foundation base. The next step was to install polymer columns directly under the foundation structure to make it possible to transfer loads to the reinforced base layers.
