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Tunnel Boring Machines (TBM)
Tunnel Boring Machines (TBM) are employed in tunnel digging, with different functions: the main one is to dig the tunnel profile, stabilise the digging front, and carry excavated soils away from the tunnel head. When digging in soft and unstable soils, two different types of TBM are employed: Slurry Shield Machines and Earth Pressure Balance Machines (EPBM). The main difference between these two types lies in the method used to stabilise the excavation front. Slurry Shield machines use bentonite or polymer slurries injected onto the head of the tunnel to cool it down and prop up the front of the working face. Further, slurries form a cake which, in turn, stabilises and seals the tunnel face. In EPBM, pressure digging of the soil provides the necessary support to the working face.
In this latter case, the soil is conditioned with foaming agents and additives selected depending on soil features and EPBM specs. Our products can be employed with every available technology and under all working conditions. We can also provide customised solutions to meet specific requirements.
BENTOGEL PL
cement-stable sodium bentonite with fast swelling, recommended for back-fill grout (annulus grout)
BENTOGEL HP2
high-yield sodium bentonite, recommended for slurry-shield tunnelling. Provides good soil stabilisation and cutting removal
BENTOGEL HP3
very high-yield sodium bentonite for slurry-shield tunnelling. Provides good soil stabilisation and cutting removal
BENTOGEL Y
Extra high yielding bentonite for high performance cementitious slurries with low dosage of bentonite
SIFAST L
cement set accelerator used for back-fill grout
SITARD L
fluidifier and cement set retarder used for back-fill grout. Improves workability up to 72 hours
DISSIP L
liquid anti-stick additive. Used also as a slurry thinner
SIFOAM HPX-L
biodegradable foaming agent used as a soil conditioner for earth pressure balance machine
SIPOL S
polymer (in powder form) used as an anti-clay agent for slurry shield machine
SILIQ LV
polymer (in liquid form) used as an anti-stick agent for slurry shield machines. Recommended also to enhance foam half-life for earth pressure balance machines
SICEL SX
cellulosic polymer used as a viscosifier in drilling muds. Also recommended to enhance foam half-life for earth pressure balance machines
SIPOL SEAL
super absorbent polymer powder. Absorbs up to 200 times its own weight. Used as a waterproofing agent
JETSOL N
Alkaline based setting accelerator for shotcrete