150 years 150 years Jim Lindsay Head of UGC, NAFTA 14 September, 2016

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Soil Conditioning Additives

EPB Machine – The operational principle

To be able to fill the working chamber completely, a certain pasty rheology and impermeability of the excavated soil is necessary

This transformation can only take place through the addition of soil conditioning agents

Pressure equilibrium between the surrounding soil / groundwater and the mix soil in the chamber (gives us the earth pressure balance = EPB)

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• Working Chamber

Tunneling in Soft Soil

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EPB Shield - Foam Comparison

Different foams have different capacities

Foaming capacity

Stability

Anti-clay capacity

Rheological impact (liquefaction /stiffening)

Drying-up capacity

Foam Quality over wide range of FER and output quantity

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FER = 8 FER = 20 FER = 14

EPB Shield - Foam Properties for Excavation

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AIRE

Foam Generators - designs and shapes

Different Designs / Shapes / Media

Different Bubble Structures

Soil Conditioning Types and Application

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Foams Allow filling of the working chamber Increase TBM speed Decrease abrasion, torque, temperature

Anti-clay-additives Decrease clogging, adhesion, transportation problems Increases TBM speed

Polymers Increases soil adhesion, impermeablity Decreases liquid soil consistency Decreases settlements

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EPB Shield - Foam Capacities

LUBRICATION CAPACITY

DRYING CAPACITY RHEOLOGICAL

IMPACT

highly stable foam to hold the face pressure and maintain the rheology of the excavated

ground much longer than conventional foaming agents.

Changing the Rheology of Soil - Soil Lubricating Foams

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soil addition of water addition of foam the result

EPB Shield CLOGGING with Clay

CONCLUSION Clogging of cutting wheel Clogging of screw conveyor or excavation chamber

PROBLEMS Adhesion on steel surface Cohesion of greater clay lumps

SOLUTION Addition of anti-clay polymers

Clogging of the Cutterhead

Adhesion on Cutterhead

Ineffective Tools

Closure of Opening

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Changing the Behavior of Clay

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Where each Soil Conditioner works best..

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Another Important Chemistry - SWA (Super Water Absorbers)

Allows Soil transportation in Highly Water Saturated Soils,

Increases TBM speed, Production

Decreases Abrasion, TBM Temperature , Down Time

Decreases Water Management

150 years

BASICS of Soil Conditioning