GT4R4A1 Slurry for use on slurry shield TBM

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  • Slurry for use in SLURRY SHIELD TBM

    GT4R4A1

    www.aftes.asso.fr

    ASSOCIATION FRANAISE DES TUNNELSET DE LESPACE SOUTERRAIN

    Organization member of the AFTES

    AAAFFFTTTEEESSS RRReeecccooommmmmmeeennndddaaatttiiiooonnnsss

  • Text prepared by P. LONGCHAMP (Bouygues Travaux Publics)

    with the close collaboration of:Antony BESQ (LEA) - Fabrice BONIN (JF Tech) - Bruno DEMAY (Vinci) - Michel GUERIN (Calypso)

    Alexandre GUILLAUME (MS) - Anne PANTET (ESIP-Poitiers) - Jean-Marie ROGEZ (RATP)Andr SCHWENZFEIER (CETU)

    Other members of Working Group GT 4 (Mechanized Excavation) also contributed to these Recommendations:Alain AMELOT (SPIE) - Daniel ANDRE (SNCF) - Franois BERTRAND (Chantiers Modernes) Laurent CHANTRON (CETU) - Didier CUELLAR (SNCF) - Jean-Marc FREDET (Pergolese)

    Jean-Louis GIAFFERI (EDF) - Christian MOLINES (Eiffage) - Philippe MONNET (ESIP Poitiers) - Laurent NICOLAS (JF Tech) - Paul RENAULT (Razel) and Jean-Franois ROUBINET (Vinci).

    The Working Group acknowledges the help of J. GUILLAUME (Razel) - B. GODINOT ( GTM Construction) - G. PIQUEREAU (CAP)

    of the Technical Committee for reviewing and validating the text.

    Grateful to D.P. Richards (Parsons Brinckerhoff International) for his translation review

    AFTES RECOMMENDATIONS CONCERNING

    SLURRY FOR USE IN SLURRY-SHIELD TBM

    PagesPages

    1 FOREWORD PURPOSE OF THE RECOMMENDATIONS - - 1652 BASIC ROLES AND FUNCTIONS - - - - - - - - - - - - - - - - - - - - - 166

    2.1 - General - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1662.2 Primary functions of slurry - - - - - - - - - - - - - - - - - - - - - - - - 1662.3 Secondary functions and qualities of slurry - - - - - - - - - - - 166

    3 BASIC PRINCIPLES FOR USING SLURRY - - - - - - - - - - - - - - - 1673.1 Confinement function - - - - - - - - - - - - - - - - - - - - - - - - - - 167

    3.1.1 General - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1673.1.2 Filtration - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1673.1.3 Stiffening of slurry - - - - - - - - - - - - - - - - - - - - - - - - - - 1673.1.4 Types of cake - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1673.1.5 Speed of cake formation - - - - - - - - - - - - - - - - - - - - - 167

    3.2 Transport function - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1673.3 Separation function - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1673.4 Changes to slurry during excavation - - - - - - - - - - - - - - - - 167

    3.4.1 Physical contamination of slurry by solid load - - - - - - 1673.4.2 Chemical contamination of slurry - - - - - - - - - - - - - - - 167

    4 BASIC PROPERTIES OF SLURRY AND THEIR MEASUREMENT 1674.1 Rehological properties - - - - - - - - - - - - - - - - - - - - - - - - - - 168

    4.1.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1684.1.2 Apparent viscosity (AV) - - - - - - - - - - - - - - - - - - - - - - - 168

    4.1.3 Plastic viscosity (PV) - - - - - - - - - - - - - - - - - - - - - - - - 1684.1.4 Yield point - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1684.1.5 Thixotropy and gels - - - - - - - - - - - - - - - - - - - - - - - - 169

    4.2 Physical properties - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1694.2.1 Density of slurry - - - - - - - - - - - - - - - - - - - - - - - - - - - 1694.2.2 Sand content (particles > 80 m) - - - - - - - - - - - - - - 1694.2.3 Filterability - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1694.2.4 Quality of cake - - - - - - - - - - - - - - - - - - - - - - - - - - - 169

    4.3 Chemical properties - - - - - - - - - - - - - - - - - - - - - - - - - - 1694.3.1 Presence of electrolytes - - - - - - - - - - - - - - - - - - - - - 1694.3.2 pH variation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 170

    5 - MATERIELS AND PROCEDURES FOR MEASURING SLURRY QUALITY - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 170

    5.1 Test equipment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1705.2 Procedures - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 170

    6 CHOICE OF MAIN SLURRY CHARACTERISTICS - - - - - - - - - 1706.1 Properties - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1706.2 Guiding the choice of slurry type - - - - - - - - - - - - - - - - - 170

    7 COMPONENTS OF SLURRY - - - - - - - - - - - - - - - - - - - - - - - - 1717.1 Composition - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1717.2 Choice of components - - - - - - - - - - - - - - - - - - - - - - - - - 171

    CONTENTSCONTENTS

    TUNNELS ET OUVRAGES SOUTERRAINS HORS-SERIE N 1 2005

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  • Slurry for use in SLURRY SHIELD TBM

    TUNNELS ET OUVRAGES SOUTERRAINS HORS-SERIE N 1 2005

    165

    For vertical drilling:

    The volume and sectional area of the bore-hole are relatively small, and any ground insta-bility is localized.

    The mud pressure is governed directly by itsdensity and the hydrostatic head.

    Cuttings from the cutterhead are carried up

    the hole by laminar flow to prevent erosion ofthe borehole walls. This calls for low flow velo-cities and a mud whose viscosity enables it tocarry the cuttings at that speed.

    The borehole generally goes through a seriesof sub-horizontal geological strata, but gene-rally crosses them at nearly perpendicularangles.

    For tunnelling:

    Support conditions are generally more diffi-cult , with a high risk of instability.

    Slurry pressure is produced and controlledmechanically.

    Spoil is carried by a turbulent flow regimewhich requires high flow velocity; the suspen-

    1 - FOREWORD PURPOSE OF THE RECOMMENDATIONS

    Slurry is an indispensable aspect in the use of closed face slurry-shield tunnel boring machines (TBMs), for tunnel support and for slurry remo-val. The AFTES Recommendations on the choice of mechanized tunnelling techniques (TOS No. 157, January/February 2000, paragraphs4.3.4, 6.3.3, 7.3.3, and 8.5) provide more information on this.AFTES Working Group GT 4 dealing with mechanized excavation considered it important to publish recommendations on slurry.

    The science of slurry for this kind of application is indeed relatively complex. It consists of a combination of experience and theory, as the slurryitself combines rehological, physical, and chemical phenomena. It also has to take account of another range of complex sciences, the earthsciences.

    Use of slurry for tunnelling can undoubtedly trace its origins back to drilling fluid (mud) for vertical holes. Because of their immense resources andthe economic issues involved, oil companies played a leading role in the development of the technology. Civil engineering thus benefited from awealth of prior knowledge, first in respect of deep foundations and drill holes for ground improvement, and then, some years later, for excavationof tunnels in loose water bearing granular soils.

    While the composition of tunnelling slurry is essentially the same as that of the drilling mud used in the oil industry, it does have its own specialrequirements. Some examples are given below:

    PagesPages

    8 TREATMENT OF EXCESS SLURRY (see Appendix 6) - - - - - - 1719 SLURRY SCHEDULE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 172

    9.1 Objectives - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1729.2 Preparation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 172

    9.2.1 Regulatory considerations: environment / health and safety - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 172

    9.2.2 Site conditions: project geometry, geology, geotechnics, and landtake - - - - - - - - - - - - - - - - - - - - - - 172

    9.2.3 Plant - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1729.2.4 Quality of components (water, additives) - - - - - - - - - - 1729.2.5 Consumption estimate - - - - - - - - - - - - - - - - - - - - - - - 172

    9.3 Testing implementation and follow-up - - - - - - - - - - - - - - 1729.3.1 Documentary system and checks - - - - - - - - - - - - - - - 1729.3.2 Personnel - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 172

    10 USING SLURRY - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17310.1 Reception of basic products - - - - - - - - - - - - - - - - - - - - - 17310.2 Manufacture - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 173

    APPENDIX 1: GLOSSARY - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 173APPENDIX 2: POLYMERS AND BENTONITES FOR TUNNELLING SLURRIES - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1741- General - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 174

    2 - Types of polymers used in tunnelling slurry - - - - - - - - - - - - - 1742.1 Starches and amylase derivatives - - - - - - - - - - - - - - - - - 1742.5 Polyacrylamides - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1742.6 Polyacrylates - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 174

    3 - Bentonite - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1743.1 Structure of bentonite- - - - - - - - - - - - - - - - - - - - - - - - - - 1753.2 Bentonite properties - - - - - - - - - - - - - - - - - -

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