Special foundations and footages works
Foundation is one of the most critical parts of the building. Group of companies OSNOVA manages construction of more than 100 m high buildings, which requires the use of special foundations and basement technologies.
Special foundations and footages works
Particular types of construction
Different types of injection works, including jet grouting technology, hidden laying of underground utilities, as well as any other type of work carried out in difficult ground conditions with the use of modern technologies and their combinations refer to special works. Nowadays combination opportunities enable us to design and carry out complex works in substandard conditions.
"Slurry wall" installation
Group of companies OSNOVA applies technology ''slurry wall'' for the development of underground space below the groundwater level and for creation of curtains at the base of hydraulic structures. This type of fencing is made extracting soil under protection of bentonite slurry. Then, the reinforcing cage is established, and the solution is replaced with concrete. Production work is carried out continuously.
The technology enables subsequently to use the "slurry wall" as a carrier system as well as a system that excludes groundwater access to the underground operated facilities.
For the first time in Ukraine, the technology of "slurry wall" was applied by the company OSNOVA-SOLSIF, which is a part of Group of companies OSNOVA. Its use is fully justified in the construction of large objects. Sometimes the "slurry wall" is the only viable technology for the construction of underground parking. This method can fundamentally solve the problem faced by the customer in the city center: narrow areas of construction sites, restriction in movement, maintaining the integrity of the buildings, minimization of sewage discharge, environmental safety.
Our equipment enables us to build impervious diaphragm
- In the body, and the basis of the dams
- At the base of concrete dams
- The body of the dam and the basis of upland reservoirs PSP, nuclear power plant cooling pond, on the sides of the channel
- Along the perimeter of septic tanks and sludge tanks of oil refining, chemical and metallurgical plants
- Along open pit mining and large construction pits instead of dewatering
This technology is especially effective for the protection of quarries and pits from groundwater inflow, as trench walls have plastic deformation and can keep high pressure. Our equipment is used for the construction of load-bearing walls
of the trench of
- Underground part of the machinery rooms of PSP
- Buried and semi-buried NPP
- Recessed part of subway entrances
- Various underground tanks
- Subway tunnels of shallow emplacement
- The underground part of industrial and civil buildings
- In the form of walls and embankments abd as retaining walls to hold the sliding slopes
- Berthing piers in the sea and river ports, etc.
To produce waterproof diaphragm wall in 600-800 mm thick ground the Group of companies have systems based on cranes LIEBHERR with a mechanical cable grabs, the use of which provides vertical structure of the future building. Additionally, sets of equipment for cleaning and transporting bentonite slurry on the site.
Drilling and bored piles installation
Installation of drilling and bored piles is performed by the Department for pile-drilling works of Group of companies OSNOVA.
Bored piles are used as a special kind of foundation for a new construction, as well as for strengthening of the foundation for reconstruction and walled pits. The advantage of this installation is the lack of driving dynamic effect on soil and foundations of existing buildings, which is an important factor in the management of construction in restricted urban areas.
Bored piles are performed by drilling a well under the protection of bentonite slurry, installing the reinforcement cage in it and filling the holes with concrete mix. Bored piles can serve as elements of foundations and walling under difficult ground conditions. Depending on the stability of the well walls, their drilling is produced under the protection of core shells or without them. Work is carried out using modern technologies, including the ''through-screws'' technology.
Group of companies OSNOVA offers a wide range of technologies for installation of bored piles of any diameter.
To install bored piles with a diameter 420-1200 mm with a drilling depth up to 35 m we use highly efficient drilling sets of the following brands: LIEBHERR, SOILMEC, CASAGRANDE. Quality control of piles is conducted using testing equipment installed on these sets.
In the most severe ground conditions we successfully apply the Italian drilling sets SOILMEC R622 and R825, which opportunities enable us to install bored piles with fastening wall using core shell with its diameter up to 2500 mm, drilling depth is up to 50 m.
In addition, our company possess methods of executing bored piles with a diameter up to 1500 mm with an enlarged pile base up to 2600 mm with a depth of drilling up to 32 meters with recoverable and unrecoverable core shells, submersible hydraulic vibrator PTC 30NI.
Installation of CFA piles
Installation of CFA piles is performed by the Pile-drilling Department of Group of companies OSNOVA.
CFA piles are made by replacing the soil drilled with concrete mixture supplied to the bottom of the well through the hollow auger under pressure. Reinforcement cages are set in poured concrete on the design elevation. These piles are the elements of the new foundations of civil and industrial buildings and structures, they strengthen the existing foundations in almost any soil conditions, including subsiding soils, and serve as cladding structure.
Applying CFA piles is the most efficient in space-restrained building sites, since it does not require the use of large equipment and can eliminate a large amount of excavation.
The advantage of CFA piles is primarily the speed of their performance achieved by using testing equipment, and its reliability.
Group of companies OSNOVA offers a wide range of technologies for installation of CFA piles of any diameter. To produce CFA piles with a diameter of 0.4 m to 1.2 m, the company uses special construction equipment, performing work without displacement of soils with a high groundwater level and significantly reducing the time of construction. Performance speed for such piles is 100-150 cubic meters per shift.
Under the most severe ground conditions we successfully apply the Italian drilling complexes SOILMEC R622 and R825, which opportunities enable us to install CFA piles of 1200 mm diameter with a depth of drilling up to 35 m.
Micropiles installation technology has been recently in high demand, as it enables to manufacture micropiles using mini-equipment in restricted areas, basements, in other cramped areas.
Micropiles can be used to install pile foundation of new buildings, or strengthening the foundations of existing buildings and structures on the stage of repair or reconstruction
Group of companies OSNOVA offers a wide range of technologies on the installation of CFA micropile with the diameter of 300 mm and a length up to 25m. The decision to use micropiles is made on the basis of engineering-geological conditions and the conditions of the work.
In line with ground anchors micropiles are widely used in the installation of retention walls or fences pits. Additionally, based on Group of companies OSNOVA successfully applies micropiles in the implementation of landslide protection activities, using them to create retention walls or as a dowel (inclined piles) to increase the degree of slope stability.
Apart from this, along with the traditional injection borehole, we use injection using sealing in the specified range or the entire length of the pile. Thus, along the slope we use vertical and inclined micropiles by crushing or pulling loads with different types of reinforcement. And regarding the method of penetration - drilling or crushing ones.
Compared to other methods of strengthening the foundations micropiles are better considering speed, reliability and environmental friendliness of production.
In construction practice, when doing repairs, reconstruction and restoration of buildings and structures, as well as the construction of new buildings on unstable ground and in restricted urban areas, with high-rise construction you can often face very common situation when conventional building technology solutions can not ensure the implementation of the set tasks. In such cases, as a rule, the only possible solution is the use of jet grouting. This technology can be applied in a variety of soils and sludges from peats to "soft" rock, regardless of their chemical composition, moisture content of plant residues, permeability etc.
The point of Jet Grouting is to use the energy of high-pressure jets of water or cement slurry to convert the properties of the soil mass destructing and simultaneously mixing soil with cement mortar mix-in-place (mixing on the spot). After solution hardening a new non-shrinking and waterproof material is formed, it is soil-cement, which has the necessary strenth and deformation characteristics.
Using different techniques of work performance it is possible to get soil with improved properties in the form of a cylindrical jet-grouting columns (jet column, diameter from 500 to 1200 mm) or flat wall (flat jet with a wall thickness of 200to 400 mm). Diameter and strength of the material of the soil-cement columns largely depend on the geological characteristics of the soil, cement consumption and technological processing modes used to strengthen the soil.
The advantages of jet grouting technology include its efficiency, high performance, the ability to carry out work in cramped conditions, lack of noise and vibration in the operations, environmental friendliness of all production operations, the ability to perform work at a given depth interval.
Installation of ground anchors
Ground anchors have been successfully used to ensure strength and resilience of buildings under different engineering-geological conditions, construction of underground facilities near the existing buildings in cramped conditions, anti-landslide measures and slope stabilization.
Ground anchors can be constructed both for temporary and long-term use.
Group of companies OSNOVA have various technologies on the installation of ground anchors ranging from CFA anchors to mechanical ones with various loads.
Аnchor with rope anchor rod manufactured by the French company technology "Soletanche-Bachy" is put into practice more often and it can withstand loads of up to 120 tons.
Installation of gravel piles
One way to improve the construction properties of soils of the underlying foundation is to install crushed stone piles. Gravel piles are performed in order to give soil masses some new features under the entire area of the building or part of it, so that various elements of the structure (single or strip foundations, gratings, baseplates) could work in a certain way, in accordance with calculations, operational margins and standards for designing and operation of facilities.
Gravel pile should not be seen as a foundation element, but as ground array with improved performance due to the use of crushed stone piles.
Crushed stone piles аре used to reduce general and non-uniform sediment to improve the bearing capacity of the soil. They also serve as drains, speeding up the natural process of consolidation, as well as to reduce the risk of dilution.
Crushed stone pile is a trunk of 50-60 cm in diameter consisting of coarse material that fits and is sealed with radial vibrator. A gravel pile load passes through the dirt layer with weak quality characteristics to more durable underlying layer. Depending on soil conditions location of gravel piles can be 1.5-2.0 m, and depth - up to 10m -12m.
The Group of companies OSNOVA apply on gravel piles to prepare foundations for such structures as road embankments, retaining walls, warehouses, low-rise residential buildings, industrial buildings or shopping centers, bunkers and tanks of various kinds, sewage treatment plants.