Method of strengthening the soil-foundations and foundations of buildings

Nowadays in Ukraine the number of the buildings under the threat of collapse is increasing. It is caused by landslide phenomena, rising of ground waters level, critical condition of underground communications (sewage system, waterpipe, heating mains), etc.  This leads to foundation, wall (occurrence of cracks) and floor slab destructions, decreasing of bearing capacity and, in consequence, building collapses. This problem can be solved by strengthening the soil-foundations and breaking buildings foundations.

There were some methods of strengthening works:

►Various pile-sinking;

►Wall in trench bearing reinforced concrete underground construction;

►Strengthening the soil-foundations by grouting silicatization or with synthetic pitches.

All these methods have a range of considerable drawbacks.

►The Pile bases:

• Driven piles require a large number of excavation works which increase costs and demand free space above fixed their base. Besides we have to use percussion and vibrating machinery and devices, that can cause dangerous deformations and even destructions of not only already repairing building but also nearby one. This also requires large-sized machinery that leads to a limited range of its application (it is not allowed to conduct works inside buildings and in case of foundation strengthening the works can be conducted only outside, thus we do not achieve the result).
• Embedding piles require creation of repulse of jacks that can lead to destructions of repaired buildings;
• Bored piles require application of large-sized equipment that leads to partly disassembling of repairing buildings and constructions and increase of terms and costs of works implementation.

►Placing of solid abutment plates and strengthening of abutment elements on the foundation foot:

• A large number of excavation works leads to increase in terms and cost of strengthening works.
• High danger and complexity of strengthening works;
• Without strengthening of the soil-foundation we do not guarantee the necessary result.

►Soil strengthening with synthetic pitch:

• This method can be used due to high prices for input materials and necessity in pumping them in soil, besides it is environmentally dangerous.

Silicatization:

This method is highly expensive and environmentally dangerous, besides it doesn’t strengthen bearing capacity of soil. Application area of methods of soil strengthening with synthetic pitch and silicatizationis limited by engineering and hydrogeological conditions of the region.

All listed above methods have long term works realization, high costs, (application of large-sized and energy-intensive equipment), economic losses, caused by functioning shutdown of repairing object. These methods can be applied in constrained conditions, especially in buildings basements.

We have developed (and patented) a new method of foundations strengthening and stabilization of building subsidence.

The essence of a new method includes strengthening grounds by injection of solidify mortars with high sedimentation resistance, penetration capacity and high bearing capacity , based on portland cement  and stabilizing additives. Unlike other existing injection methods, our method doesn’t require drilling holes with big diameter, that means there is no need in large-sized tools and there is a possibility to work in constrained conditions, especially in building basements that enhances fixation effectiveness. The penetration capacity of the mortar (filling microcracks)  considerably rises thanks to components of solidify mortar and its pumping in soil, that widens strengthening are and decreases the number of drilling holes that consequently reduces cost of works.

►The advantages of our method:

• Increase of bearing capacity of fixed basis by achieving a relatively higher strength of backfill stone;
• Possibility to drill holes of small diameter and of given depth. It allows to use small-sized and low power-consuming equipment which makes work in remote places possible and reduces costs of works;
• Reduce of fixation cost due to law prices for components of solidify mortar
• Use of fluids of high penetrating power, which is run by the laminar fluid motion. It reduces the number of holes considerably and optimizes expenditures;

►The given method has been adopted since the end of 80th in:

• construction of overground and underground objects of coal mines in Western Donbass (sewage pumping stations, collectors, water tanks, mine drainage sumps, shafts and underground coal bunkers);
• strengthening the bed soils and foundations of buildings of Kherson Shipbuilding Plant;
• strengthening the soil foundations and waterproofing of  way hall  of the “Zoloti Vorota” station of Kyiv Metro;
• strengthening the upper slopes of dam of Krasnoplovsk’s hydroelectric system ;
• strengthening the soils, waterproofing  and reconstruction of the dock parts of the pumping stations of Dnepr-Donbass and Dnepr-Ingulets water lines;
• strengthening the bed soils and  foundations of Odessa Portside Plant’s buildings
• strengthening the bed soils and foundations of offices and studio of metal products manufacturing of “Formula” Ltd. in Brovary.