TECHNOLOGIES - JET GROUTING
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Jet grouting improves soil mechanical and permeability properties by using high-speed jets of water/cement mixtures injection treatment. Jet grouting can be advantageoudiy in the following • difficult logistic conditions • confined spaces • presence of obstacles to cross • high-depth treatment with crossing of voids Suitable soils The jet grouting technique allows to improve a wide range of soil types. As it is based on soil erosion, soil erodibility is crucial to the final result. The more consistent the soil to be treated, the smaller the column diameter. Therefore, larger columns can be...

Consolidated elements - usually columns - are constructed using small-diameter drilling {100 to 140 mm), by means of light and easy to handle rigs. Moreover this technology allows to realize consolidated soil elements and overcome underground obstacles Jet grouting is usually performed down to depths of 20- 30 m. However, special projects reaching 100 m-depth have also been realized. All jet grouting techniques envisage a preliminary phase of drilling, followed by extraction and rotation at preset values, and simultaneous pumping of the fluids at high Depending on the number of fluids used,...

Before starting to work, the position of each drilling point (distance between the centres and from the reference points) must be determined and staked out on the ground, or marked by means of a satellite positioning system. The treatment parameters are chosen only after conducting preliminary field tests. In case of very cohesive soils, the pre-cutting technique may be used. It consists in a pre-treatment with water under pressure which is conducted during extraction or The grout must be injected immediately after drilling, by extracting and rotating the string at pre-set and constant...

TREVI has recently designed and patented a new high- efficiency monitor (ETJ = Enhanced TreviJet). The ETJ system includes a cutting-edge monitor and standard jobsite equipment for jet grouting (mixing systems, pumps, drilling rigs, jetting rods).The monitor is fitted with two curvilinear conduits that reduce head losses caused by any sudden variation of the fluid direction (from axial in the rods to radial through the nozzles). In this way, the jet is extremely consistent and allows to significantly improve jet grouting efficiency, and to obtain column diameters larger than the ones...

The equipment needed for jet grouting are the following: drilling rigs, concrete batch processing plants, high pressure pumps, compressors. The type and number of equipment depend on the technique used. Installed power ranges from min. 600 HP (monofluid) to max roughly 1000 HP (triple fluid). Installed power Water storage tanks Concrete batch processing plant High-pressure pump T2 triple fluid system

Properties of consolidated soils The physical and mechanical properties of consolidated soils mainly depend on the type and composition of the soil itself, as well as on the cement quantity which remains in the ground. Unconfined compressive strength values of 6-r15 MPa can be obtained in coarse alluvial soil, whereas strength is considerably reduced in the presence Average soil permeability values range from 10"6 to 10" Strength depending on lithology and cement quantity The physical-mechanical characteristics of the treated soils depend mainly on the nature and composition of the soil...

DPS display DPS JET (Drilling Positioning System) The DPS has been developed to control the position of monofluid and bifluid jet grouting columns. The device allows to make measurements within an area of +/- 60 degrees from the vertical. This control is extremely important in the execution of bottom plugs and deep waterproofing shields. he DPS provides inclination and direction data, the standard deviation value of each of the abovementioned measurements, the deviations calculated in North-East and polar coordinates for each stop and the stop heights. APS (Automatic Positioning System) The...

The jet grouting technique is suitable for a number of applications, when other techniques cannot be used. In particular, the following applications can be mentioned: • Consolidation of existing foundations • Reduction in subsidence for new structures • Retaining walls for excavation protection • Waterproof curtain walls • Preliminary consolidation works (from the interior or

The common shapes of jet grouting treatments are cylindrical columns that are obtained by keeping constant rotating and raising speeds, or thin layers, which are constructed at a constant raising speed, without rotating Other shapes can also be obtained by modifying the rotation speed, to realize cylindrical sectors. TREVI has patented an innovative technique which allows to realize pseudo-elliptical columns. This geometry is obtained by modifying the rotation speed in a planned way. It allows to maximize the use of jet grouting columns when the treatment is aimed at constructing a curtain...

World leader in ground engineering, Trevi has been working for more than 50 years throughout the world, strengthening its ability to provide solutions to any ground engineering issues. Trevi works in the field of special foundation, soil consolidation, dam remedial works, tunnel construction and consolidation, marine works, rehabilitation and cleanup of contaminated sites and construction of underground automatic multi-storey car parks. Trevi is committed to continuous innovation and search for solutions to complex problems of civil engineering worldwide. Experimenting cutting-edge...