Soil ImprovementDrilling & Grouting
Grouting in general terms is known as the injection of a fluid which sets or gels into a crack or voids. The scope of grouting covers a wide range from simple filling operation to complex engineering application, which can be used either for reduction of permeability or strengthening of foundations. Commonly used grout materials are cement and water, including certain chemicals, which can be used as additives.
Access to the cracks or voids is usually provided by holes drilled at fixed spacings by destructive drilling technique such as top-hammer or down-the hole hammer systems using an air compressor.
The injection of grout has to be limited or adjusted by suitable pumps.
Jet Grouting is a general term for a variety of techniques employing one, two or three fluids to mix in situ or replace soil underground with cement based grout mix. The common denomination of those methods is the use of very high pressure in the injected fluid, which mixes or displaces the soil, rather then permeating it as in conventional grouting techniques.
The possibility of creating treated horizons or columns of improved soil results in a variety of applications ranging from vertical cut-offs to bottom plugs, from underpinning to underground strutting elements.
Vibro Compaction/Stone Columns
Vibro compaction is a technique used to densify granular soils which are typically clean sands (fines content generally less than 10%) using special vibrators.
The vibratory energy is used to rearrange the particles of the sand in a denser state. The vibrations are produced by a rotating eccentric probe driven into the soil down to the required depth.
Cohesive and mixed layered soils generally do not densify easily when subjected to vibration alone. Hence, the Vibro-Replacement, Stone Columns has been specifically developed as improved technique of the Vibro process, widening the range of soil types that can be improved with the deep vibratory method.
With Vibro-Replacement, dense columns of crushed material (coarse gravel) are formed into the soil in order to increase bearing capacity, reduce settlement, improve shear resistance and, in seismic areas, mitigate the potential for liquefaction.
The stone columns and the in-situ soil form together an integrated system having lower compressibility and high shear strength.
Deep Soil Mixing
Soil Mixing is a method of soil improvement by which materials of various types, but usually of cementitious nature, are introduced and blended into the soil through hollow, rotated shafts equipped with cutting tools, and mixing paddles or augers, that extend for various distances above the tip. The ‘binder’ materials may be injected in either slurry or dry form. The treated mass that results generally has a higher strength, lower compressibility, and lower permeability than the virgin soil.
TREVI group has developed advanced tools and methods in order to adapt the technology to a larger soil spectrum.