TECHNOLOGY - INJECTIONS
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Injection technique is used in civil engineering to improve the mechanical and permeability properties of soil, rocks and brick or concrete work. From a functional point of view, two types of interventions • temporary intervention, to make excavation possible in unstable soil or under water table; • permanent intervention for the consolidation of foundation soils, the creation of watertight structures, or the structural restoration of brick or concrete works. Temporary injection - Milan Underground, Line 3. Waterproofing and consolidation injection. Permanent injection - Bamiyan,...

Grouting systems Systems with packer in bedrock Classification of grouting systems according to the European Standard EN 12715 'Grouting', Chapter 8.4, table 4) UPSTAGE GROUTING stand-pipe drilling l"stage 2"*stage J"Vage last stage riote • i ■• -i- grouting grouting grouting grouting grouted From an operating point of view, grouting is divided into loose soil grouting and in rock grouting. Rock fissure grouting is performed directly into the open borehole. In this case, downstage or upstage • With the upstage method (also named 'ascending stage*), the borehole is drilled at the project...

Grouting systems Grouting in weathered rocks or loose soil can be performed by using tubes fitted with check valves, which are driven into the ground after drilling. The valves are usually rubber sleeves that cover lengths of the tube featuring holes: they inflate under pressure and force the grout through the holes preventing it from flowing back. Grouting is performed by isolating the tube lengths by means of an inflatable double packer. In particular the following methods can be used: ■ MPSP method [Multi Packer Sleeve Pipe), designed and developed by RODIO-TREVI to treat weathered •...

To grout fine-grained soils, Trevi has designed the TMG system (Trevi Mufti Grouting): a group of small-diameter tubes with different lengths and fitted with one single valve are inserted into each hole. Every tube is directly connected to the grout delivery line, with no need for sliding the packer down into the hole. In this way it is possible to grout different levels of the same borehole simultaneously and in a selective way (with different preset parameters). The tubes (with high burst strength) have different colours, each being also identified by a progressive number associated with...

Cement-based grouts are usually the choice for rock formations or loose coarse-grained soils. Cement grouts can be stabilized by means of pre- hydrated bentonite, whereas they are made less cohesive and more fluid by adding special formulations and deflocculating-fluidifying additives (MISTRA grouts). There is evidence in literature that successful grouting depends in the first place on the size of the solid particles of the injected grout compared to the dimensions of the gaps or rock fissures to be injected. • For the injection of slight rock fissures and finer-grained soils, fine cement...

Grouting plants Grouts are prepared and pumped by means of specific mixing and pumping plants. The storage, dosing and mixing plants can include a number of equipment for the preparation of different types of cement or chemical Grouting plants include agitators in which ready-to- inject grouts are stored. They feed the pumps and injectors to inject the grout into the borehole, which can be a few hundred metres away. SOILMEC SGJ-8 grouting plant GPC: data input and parameter controls during execution Borehole length Injected length MISTRA grout SILACSOL grout grout injection Grout delivery...

Compensation Grouting Tunnelling and underground excavation under a thin cover between the tunnel roof and ground surface inevitably cause subsidence and therefore damage to the overlying buildings. To mitigate or eliminate the effect of subsidence, Compensation Grouting is used. The main idea of Compensation Grouting is to inject grouts into the soil between the tunnel and the overlying structure at risk, in order to offset the settlements caused by tunnelling, through induced To this end, grouts are injected at relatively high pressure to displace the soil. Fracture grouting or compaction...

Injections can be used for interventions aimed at • Realisation of cut-off walls under new dams improvingthefoundationsoilandrocksof new buildings, . poy^jjation soil consolidation of new structures suchas: buildings • Consolidation and/or waterproofing of soils and rocks before tunnelling or subway excavations • Realisation of watertight bottom walls to allow for excavation under water table Parbati Hydroelectric Project, Himachal Pradesh, India (2006-2008) - Waterproofing injection for the construction of a cut-off wall in the Paleo riverbed

Injections are also suitable for the restoration, retrofitting or upgrading of existing buildings to safety standards. A few examples are given in the following list: • Restoration of existing foundations (1) • Functional adaptation of buildings (2) • Recovery of sunken areas under the water table (3) • Interventions on existing dams, with the construction or integration of cut-off walls (4) or sealing of fissures in the dam body (5) • Restoration and adaptation of tunnels (6) • Construction of impervious barriers below Vibrating machine Pipes fitted with valves Treatment with ALLUVIAL SOIL...

5 - Nuraghe Arrubiu dam on Flumendosa, Sardinia (1994) - Epoxy resin injections into the dam body to stop water seepage and restore the single-piece concrete nature of the dam. Soil injected with SILACSOL grouts Tunnel lining Head sealing with Iron grouting pipes ALLODIAL SANDSTONE-MARL ALLODIAL SANDSTONE-MARL CONGLOMERATE MARLY LIMESTONE MORENIC 6 - Milan-Chiasso railway line - Monteolimpino 2 tunnel (2003-2004): restoration of a stretch under the water table following the settlement of the invert (caused by water seepage and simultaneous transport of solid materials into the tunnel due to...