2008 G&T 01 Testing PPL

R. Plinninger & U. Restner: Abrasivity Testing, Quo Vadis

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Abrasivity Testing, Quo Vadis?

- A Commented Overview

of Abrasivity Testing Methods

Ralf J. Plinninger & Uwe Restner

Kurzfassung: Der stetig zunehmende wirtschaftliche Druck auf Tunnelbau und Rohstoffgewin-

nung fhrt zu einer steigenden Bedeutung von Untersuchungsverfahren zur Bewertung der Ab-

rasivitt von Fest- und Lockergesteinen. Derartige Untersuchungen knnen mit einer Vielzahl

von Verfahren durchgefhrt werden, die von vor-Ort-1:1-Untersuchungen ber Modellversuche

mit vereinfachten Werkzeugen bis hin zu mikroskopischen oder chemischen Untersuchungen

eine weite Bandbreite an Untersuchungsmastben einschlieen. Der vorliegende Beitrag gibt

einen berblick ber die derzeit wesentlichsten Untersuchungsverfahren, versuchstechnische

Aspekte ihrer Anwendung, angewandte Klassifizierungsschlssel sowie Einsatzerfahrungen.

Abstract: The growing economic pressure on tunnelling and mining operations worldwide has

lead to an increasing importance of investigation methods for assessing the abrasivity of rock

and soil. Such investigations can be based on a wide variety of testing procedures and stand-

ards covering a wide span of scale, ranging from on-site real-scale drilling tests to model tests

with simplified tools and microscopic and chemical analysis of rocks and minerals. This paper

gives an overview over some of the most important procedures, technical aspects of their use,

classification of testing results and the current state of experience.

Keywords: Wear Prediction, Rock Abrasivity, Testing Methods, Laboratory Investigations, CAI,

ABR, LCPC, RAI.

1 Introduction

The growing economic pressure on tunnelling and mining operations worldwide has in the past

decades lead to a increasing importance of prediction models for tool wear and investigation

methods for assessing the abrasivity of rock and soil. In the preliminary phase of an under-

ground project such values are of crucial importance for the choice of an economic excavation

method and wear-related cost estimations. During operation these are basic input parameters

for adjusting tools and machinery as well as for judging contractual aspects of the works.

This paper is intended to give an overview of some of the most important recent procedures,

technical aspects of their use, classification of testing results and the current state of experi-

ence.

2 Scales of Abrasivity Investigation

The term abrasivity describes the potential of a rock or soil to cause wear on a tool. As this

potential depends significantly on the specific circumstances of the observed system (e.g. in-

volved tools, mechanisms of excavation, temperature, applied loads, etc.) it should be kept in

mind that rock abrasivity can never be an intrinsic physical parameter.


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The investigation of abrasivity can be based on a wide variety of testing procedures and stand-

ards [6]. For the estimation and discussion of investigation methods it is important to understand

that procedures cover a wide span of scale, ranging from on-site real-scale drilling tests to mod-

el tests with simplified tools and microscopic and chemical analysis of rocks and minerals (Fig-

ure 1). Depending on its individual scale and testing setup, each method is able to take different

factors into account while disregarding others.

Figure 1: Scales of abrasivity investigation, shown for the example of roadheader operation.

3 Real-scale Abrasivity Investigations

Real-scale abrasivity investigations feature the original tool and machinery layout of the chosen

excavation method. Such investigations can by subdivided into in-situ testing (for example in

pre-cuts or exploratory galleries) and large-scale testing (on large samples). Depending on the

size and how representative the testing area or sample is, such testing represents a simple

method to obtain reliable data for tool wear and excavation performance since all influencing

factors are taken into account.


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3.1 Technical Aspects of Real-scale Investigations

In order to achieve a high level of accuracy, wear and performance documentation as well as

rock mechanical testing and geotechnical documentation should follow a scheduled procedure

from the beginning of the works and should be performed regularly. Reporting of results should

give a detailed description of employed tools and machinery and encountered geological cir-

cumstances, including relevant rock and rock mass parameters. The report should then con-

clude on the calculation and classification of encountered gross tool wear rates and description

as well as statistical analysis of tool wear forms.

Examples and suggestions on this topics are presented in [23] as well as in Plinningers paper

on abrasivity assessment for drilling tools in this magazines issue.

3.2 Classification of Testing Results

A descriptive classification of rock abrasivity based on the encountered tool wear rates of drill

bits, point attack picks and TBM cutter discs based on the typically used terms is available in

Table 1.

Table 1: Classification of Rock Abrasivity and Tool lifetime for Drill Bits, Point Attack Picks and TBM cutter

discs (according to [23])

Abrasivity

Drill Bits (ref: 45 mm)

Point Attack Picks TBM cutter discs

(ref: 17)

Drill bit lifetime [drilled m/bit]

Specific pick con-sumption [picks/m]

cutter disc lifetime [km/disc]

very low > 2000 < 0,01 > 2000

low 1500 - 2000 0.01 - 0.05 1500 - 2000

moderate 1000 - 1500 0.05 - 0.15 1000 - 1500

high 500 - 1000 0.15 - 0.30 500 - 1000

very high 200 - 500 0.3 - 0.5 200 - 500

extremely high < 200 > 0.5 < 200

3.3 Correlations and Experiences

Test excavations performed solely for investigational reasons are rather expensive with respect

to personnel and material costs and so such cutting or drilling tests are carried out very rarely.

In contrast to this, preliminary works like exploratory galleries or pre-cuts are available quite

often and these measures should be used as a valuable source of information for performance

and tool wear of the methods used. There are some recent papers giving examples for the

presentation and interpretation of case studies for TBM [22] and roadheader excavation [17],

[19].

4 Model Tests Using Original Tools

Model tests using original tools (drill bits, picks or cutter discs) represent testing layouts that

have in the past provided basic knowledge about the rock fragmentation process and the inter-

action between rock and tool. Such testing devices are well suited to investigate the influence of

single tool and machinery parameters or rock parameters since nearly all influencing factors can

be accurately defined under laboratory conditions (Figure 2).


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Figure 2: Overview (left) and detail (right) from SMCs cutting frame using original point attack picks.

4.1 Technical Aspects of Model Tests Using Original Tools

At present, each testing device in this category is unique and construction as well as operation

of these devices is rather expensive. Currently only a few research institutes and machine man-

ufacturers are able to use such model tests for abrasivity and performance assessment. Since

such tests represent no standard procedures, suggestions on technical aspects cannot be

made here.


Unlike in-situ testing, laboratory tests with limited rock volume allow and require measurements

of material loss in terms of dimension or weight. Such net wear rates (expressed e.g. as loss in

weight per excavated volume of rock e.g. [g/m]) may then be used as input data for estimations

on gross tool wear (normally expressed as tool lifetime per excavated length or volume of rock,

e.g. [picks/m]. Consequently the same classifications apply as given for in-situ and large-scale

investigations as given in Table 1.

5 The CERCHAR Abrasiveness Index (CAI; Model Test)

The CERCHAR scratch test represents a model test with a simplified tool. The testing principle

was invented in France in the 1980s and is based on a steel pin with defined geometry and

quality that is scratched over 10 mm of a rough rock sample under a static load of 70 N (Figure

3). The CAI is then calculated from a number of single tests and with regard to the measured

diameter of the resulting wear flat on the testing needle.


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Figure 3: Testing layouts for the Cerchar Test: Original CERCHAR apparatus (left) and modified West

apparatus (right).

The extended use of this test by various manufacturers, research institutes and consultants in

the field of rock excavation has led to the CAI being one the few standard parameters for as-

sessing hardrock abrasivity. The CAI is for this purpose also referred to as the 2001 GG rec-

ommendations for the geomechanical design of underground structures with conventional

methods [13].

5.1 Technical Aspects of CERCHAR Testing

An internal 1986 CERCHAR testing recommendation [4] and a French AFNOR standard from

the year 2000 [1] are available for testing. Nevertheless a number of investigations on technical

and geotechnical influences on the testing result [10], [15] have shown that some varying tech-

nical features (mainly pin quality / steel hardness, testing frame stiffness, testing velocity and

number of tests) play an important role for the testing result. The current state of knowledge is

summarised in this magazines issue by Ksling & Thuro.

The German DGGT working group on rock mechanical investigations (AK 3.3) is currently pre-

paring a national testing recommendation for the CERCHAR test in order to improve CERCHAR

testing and to assure comparable testing results.

5.2 Classification of the CERCHAR Abrasiveness Index

Two classifications for the CERCHAR Abrasiveness Index (CAI) are used widely: The original

classification by CERCHAR, 1986 [4] and an improved scheme developed at Sandvic Mining

and Construction [18]. Both classifications are presented in Table 2 and Table 3.

Table 2: CERCHARs Classification of Rock Abrasivity from CAI [4].

CAI [ ] Classification

0.3 - 0.5 not very abrasive

0.5 - 1.0 slightly abrasive

1.0 - 2.0 medium abrasiveness

2.0 - 4.0 very abrasive

4.0 - 6.0 extremely abrasive


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Table 3: SMCs Classification of Rock Abrasivity from CAI [18].

CAI [ ] Classification

< 0.5 not abrasive

0.5 - 1.0 little abrasive

1.0 - 1.3 moderately abrasive

1.3 - 1.8 considerably abrasive

1.8 - 2.3 abrasive

2.3 - 3.0 very abrasive

3.0 - 4.5 highly abrasive

> 4.5 extremely abrasive


The simplicity of the testing principle and its ability to use relatively small rock specimens (some

cm in diameter) are the main reasons why the CERCHAR Test is used worldwide use in the

field of tunnelling and rock engineering. Given that even on-site testing is possible, the CAI is an

index which is relatively cheap and quickly available in hardrock conditions. Figure 4 shows typ-

ical CAI values for different rock types.

Figure 4: Typical CAI values for different rock types (compiled from [3], [14] and own data).

To date there are some problems in correlating CAI values gained from different laboratories

with different testing equipment, which is primarily related to the mentioned technical aspects

influencing CERCHAR testing. With more precise testing standards these problems should be

overcome in the next few years.

With a long history of application there are many experiences and correlations available to

compare the testing results of the CERCHAR test with other wear-relevant indices and parame-

ters. Figure 5 and 6 show the empirical correlations of CAI with the RAI wear index and the ABR

index value derived from the LCPC model test.


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Figure 5: Empirical correlation between CAI

and RAI (acc to. [16]).

Figure 6: Empirical correlation between CAI and ABR

(acc. to [3]).

Additionally, empirical correlations exist for estimations on tool wear rates from a given CAI

e.g. for drill bits (see paper by Plinninger in this issue), point attack picks (see Figure 7) and

cutter discs (e.g. [9]). The CAI is also referred to by more sophisticated formulas for perfor-

mance and wear prediction such as for example Gehrings system for TBM wear and penetra-

tion system [8].

Figure 7: Example for a detailed correlation between CAI, UCS and specific point attack pick wear for

22mm picks based on empirical data sets.

Nevertheless one should keep in mind that the scale of CERCHAR testing allows only the inves-

tigation of basic rock and mineral influences and neglects any influences on tool wear coming

from larger scale rock mass parameters (e.g. jointing, stress conditions, etc.). It is in this context

an interesting recent finding that the CAI increases significantly with an increasing confining

pressure applied on the rock sample [20] which is mostly similar to stress effects stated for

real scale tool wear [14].

6 LCPC Abroy Test (ABR; Model Test)

The LCPC Abroy test was developed in France in the 1970s in order to investigate and classi-

fy abrasivity related to rock crusher application. In this model mill test, the weight loss of a

steel plate with defined geometry and hardness is measured which rotates at 4500 rpm for 5

minutes in a rock sample of 500 g (Figure 8). The ABR value is than calculated from the weight


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loss of the plate. Since the sample consists of particles of a defined (relatively small) grain size

(4 6.3 mm) it is applicable to any hardrock and soil where such fine gravel may be produced

by crushing and/or separating (sieving).

Figure 8: Testing layout for LCPC Abroy test (acc. to MLPC brochure)

6.1 Technical Aspects of LCPC Testing

Since 1990 a French AFNOR standard [2] is available for testing. If the test is carried out in ac-

cordance to this standard, comparable testing results should be achieved.


Two classifications for the LCPC Abrasiveness Index (ABR) are available at present. The origi-

nal classification presented also in AFNOR P18-579 ([2], [3]) and an improved scheme devel-

oped at TU Munich and published in 2006 [24]. Both classifications are presented in Table 4

and 5.

Table 4: LCPCs Classification of Rock Abrasivity from ABR [2].

ABR [g/t] Classification

< 500 very low abrasiveness

500 - 1000 low abrasiveness

1000 - 1500 medium abrasiveness

1500 - 2000 high abrasiveness

> 2000 very high abrasiveness


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Table 5: TUMs Classification of Rock Abrasivity from ABR [24].

ABR [g/t] Classification

0 - 50 not abrasive

50 - 100 slightly abrasive

100 - 250 low abrasiveness

250 - 500 abrasive

500 - 1250 very abrasive

1250 - 2000 extremely abrasive


For application in hardrock some authors [7], [14] criticise the testing principle as not useful at

all for assign tool wear in excavation, mainly because some of the most important rock features

are destroyed during sample preparation and therefore neglected in the determination of the

ABR abrasivity index. Currently, for hardrock drilling or cutting no correlations for tool wear rate

estimation are available.

For application in soils and very weak rock, the testing principle has in the last decade seen

increased use. Nevertheless it should be kept in mind that in the course of sample preparation

some of the most relevant soil parameters are changed significantly or even discarded com-

pletely (Table 6).

Table 6: Relevant soil parameters influencing tool wear and excavation performance and their impact on

the ABR.

Relevant soil parame-ters

Parameter impact

description

hardness and abrasive-ness of grains and

considered

absolute grain sizes and grain size distribution

mostly ne-glected

material < 4 mm is discarded, material > 6.3 mm is crushed to 4-6.3 mm

grain shape / rounding mostly ne-

glected

only fine gravel particles (4-6.3 mm) are testes in their original grain shape, courser material is crushed and is tested in angular shape

soil cohesion & friction angle

mostly ne-glected

changed significantly since fines are discarded and original grain shape and grain size distri-bution is destroyed during sampling prepara-tion

binder materials (e.g. ferritic, carbonatic bind-er)

neglected if abundant, most of binding is destroyed dur-ing sampling and sample preparation

natural soil density neglected changed significantly during sampling and sample preparation

stickiness (adhesion po-tential)

neglected adhesion potential cannot be identified, since any fines are discarded

natural water content mostly ne-

glected changed significantly during sampling and sample preparation

As another major geological influence on the ABR value one has to remind that in natural sedi-

ments petrographical and grain shape features may vary with grain sizes. This fact is suggested

to be the main reason for the effect that samples prepared from different grain size spectrums

often show significantly differing ABR values (e.g. [24]).


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7 The NTNU System: AV, AVS and SAT Model Tests

NTNU Trondheims AV (Abrasion Value), AVS (Abrasion Value Steel) and SAT (Soil Abrasion)

tests are part an investigation approach, based on more sophisticated simplified model tests for

performance and wear estimation of several rock excavation methods, including drilling, hard-

rock TBM and shield excavation. The tests are used in combination with two more model tests

(Brittleness Test and Sievers-J miniature drilling test). AV, AVS and SAT tests are very simi-

lar testing layouts, based on a rotating steel disc carrying the sample material that is either

crushed or sieved to particles < 1 mm (Figure 9) and abrading a model tool from tungsten car-

bide (AV) or steel (AVS, SAT) under defined circumstances like applied load, duration and rota-

tional speed ([11], [12]).

Figure 9: Testing layout for the AV, AVS and SAT tests (according to [11])

7.1 Technical Aspects of Testing

These tests are mainly used by SINTEF, Norway and problems with comparability of testing

results have not been reported.


Since introduction in the 1960s there are a number of experiences on testing results and corre-

lations to actual excavation performance and tool wear available and NTNU has published a

series of books on this data and estimation procedures including a catalogue of drillability indi-

ces and a number of project reports on estimations e.g. for tunnelling, bench drilling, etc. (see

[11], [12] for further references).

7.3 Other Model Tests

An overview of all model tests with simplified tools invented and used in the field of geomechan-

ics and tunnelling would by far exceed this paper. Testing layouts like the Los Angeles Test,

Ball Mill Test, Dorry Abrasion Test and Miller Slurry Test are just a few more approaches used

in this field. Nevertheless recent papers show that the development of new testing layouts has

not ever come to an end. It will be one task of the near future to prove the reliability and correla-

tion of these tests in field investigations and case studies.


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8 Geotechnical Indices

In contrast to model tests, geotechnical indices use a different approach for abrasivity assess-

ment. Instead of testing specific (simplified) wear systems, they relate to standard intrinsic rock

(and soil) parameters. The difference in these indices is the choice of different input parameters

and their different weight in the calculation formulas. Some of the geotechnical wear indices

most often applied are:

Geochemical parameters like SiO2 and Al2O3 content

Abrasive Mineral Content (AMC), Vickers Hardness Number of the Rock (VHNR) and

Equivalent Quartz Content (EQC)

Schimazeks wear index [21] and the modified Schimazek index presented by Ewendt

[7]

the Rock Abrasivity Index (RAI), presented in detail in the following chapters

Some of these factors are not only used as a stand-alone parameter for correlation of tool wear

but included in more sophisticated prediction formulas such as for example Dekeths Specific

Wear Equation (SPW; [5]).

8.1 The Rock Abrasivity Index (RAI)

The Rock Abrasivity Index, RAI is a geotechnical wear index applicable to hardrock. The RAI

tool wear assessment procedure suggests an investigation program taking into account the hole

range of scale from rock mass to mineral scale. It is based on easy-to-obtain, conventional rock

and rock mass parameters which in most cases are already available from standard stability

assessment of the underground opening [14].

Based on the "mineral scale" and "rock scale" investigations, the RAI is calculated for relevant

rock types by multiplying the rocks Unconfined Compressive Strength (UCS) and Equivalent

Quartz Content (EQC).

8.2 Technical Aspects of Determining the RAI

The use of UCS and EQC as the very basic input parameter is one of the main reasons, why

the RAI has found a relatively fast and broad application since its introduction in 2002. Since

these standard geotechnical parameters are the subject of various testing standards and rec-

ommendations as well as technical influences on both parameters are well known, this also as-

sures a worldwide reliability for the index.


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8.3 RAI Classification

A classification for rock abrasivity is available from [14] and presented in Table 7.

Table 7: Classification of Rock Abrasivity from RAI [14].

RAI [ ] Classification

< 10 not abrasive

10 - 30 slightly abrasive

30 - 60 abrasive

60 - 120 very abrasive

> 120 extremely abrasive


The RAI has to date shown good results for the estimation of button bit wear, which is present-

ed in this magazines issue in the paper by Plinninger. A correlation between RAI and CAI is

given in Figure 5 and typically achieved RAI values for different rock types are presented in Fig-

ure 10.

Figure 10: Typical RAI values for different rock types.

9 Conclusions

The presented overview shows that there is a vast amount of testing approaches available for

the investigation of rock and soil abrasivity. Judging from the total number of tests available,

model tests with simplified tools prevail and there are even new testing principles being devel-

oped in order to allow abrasivity assessment from a - possibly fast and cheap to obtain - index

value. Nevertheless quite a number of researchers who have undertaken case studies on tool

wear (e.g. [5], [7], [14]) have found that it is not as easy as hoped to transfer the abrasivity val-

ues determined in a model system to real rock excavation.

Geotechnical wear parameters, based on simple rock and soil parameters represent a very

common approach of engineering geologist to geotechnical questions. Some of the presented

wear indices are in use for at least 50 years or more and their reliability is based upon the fact


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that the testing procedures required for their determination are standard tests available

throughout the world in a mostly similar form. As standard parameters they also allow what a

special test does not allow: The use of empirical estimations where no measurements are avail-

able and empirical judgement on how representative a chosen value is.

This papers title begins with a somewhat provocative question: Abrasivity testing quo vadis?

From the authors point of view, abrasivity testing has since the 1970s focused merely on some-

times sophisticated model testing setups. In order to understand the abrasiveness of a rock,

rock mass or soil in its complete geological complexity, going forward the focus should be on

representative real-scale investigations and case studies on the one hand and the acquisition of

relevant standard rock, rock mass and soil parameters on the other.

10 References

[1] AFNOR: NF P 94-430-1: Roches Dtermination du pouvoir abrasive d'une roche Partie 1:

Essai de rayure avec une pointe, October 2000.

[2] AFNOR: P18-579: Granulats - Essai dabrasivit et de broyabilit, Dcembre 1990.

[3] Bchi, E., Mathier, J.-F. & Wyss, Ch.: Gesteinsabrasivitt - ein bedeutender Kostenfaktor

beim mechanischen Abbau von Fest- und Lockergestein. Tunnel: p. 38-43, 1995.

[4] CERCHAR - Centre d Etudes et Recherches de Charbonnages de France: The CER-

CHAR Abrasiveness Index, Verneuil: 1986.

[5] Deketh, H.J.R.: Wear of rock cutting tools - Laboratory experiments on the abrasivity of

rock, Rotterdam, Brookfield: Balkema, 1995.

[6] DIN (Deutsches Institut fr Normung e.V.): DIN 50320 - Verschlei. Begriffe, Systemana-

lyse von Verschleivorgngen, Gliederung des Verschleigebietes, Berlin: Beuth, 1979.

[7] Ewendt, G.: Erfassung der Gesteinsabrasivitt und Prognose des Werkzeugverschleies

beim maschinellen Tunnelvortrieb mit Diskenmeieln, Bochumer geol. u. geot. Arbeiten,

33, Bochum, 1989.

[8] Gehring, K.: Leistungs- und Verschleiprognosen im maschinellen Tunnelbau; Felsbau

13, 6: p. 439-448, Essen: Glckauf, 1995.

[9] Maidl, B., Schmid, L., Ritz, W. & Herrenknecht, M.: Tunnelbohrmaschinen im Hartgestein,

Berlin: Ernst & Sohn, 2001.

[10] Michalakopoulos, T.N., Anagnostou, V.G., Bassanou, M.E. & Panagiotou, G.N.: Technical

note: The influence of steel styli hardness on the Cerchar abrasiveness index value, Inter-

national Journal of Rock Mechanics and Mining Sciences, 43: p. 321-327, 2006.

[11] Nilsen, B., Dahl, F., Holzhuser, J. & Raleigh, P.: Abrasivity testing for rock and soils,

Tunnels and Tunnelling International Magazine, 38, 4: p. 47-49, 2006.

[12] Nilsen, B., Dahl, F., Holzhuser, J. & Raleigh, P.: SAT - NTNUs new soil abrasion test,

Tunnels and Tunnelling International Magazine, 38, 5: p. 43-45, 2006.

[13] GG sterreichische Gesellschaft fr Geomechanik: Richtlinie fr die Geomechanische

Planung von Untertagebauarbeiten mit zyklischem Vortrieb, 2001.


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[14] Plinninger, R.J.: Klassifizierung und Prognose von Werkzeugverschlei bei konventionel-

len Gebirgslsungsverfahren im Festgestein, Mnchner Geologische Hefte, Reihe B, 17 -

Angewandte Geologie, Mnchen: Hieronymus, 2002.

[15] Plinninger, R., Ksling, H., Thuro, K. & Spaun, G.: Testing conditions and geomechanical

properties influencing the CERCHAR abrasiveness index (CAI) value, International Jour-

nal of Rock Mechanics and Mining Sciences, 40: p. 259-263, 2003.

[16] Plinninger, R.J., Ksling, H. & Thuro, K.: Wear Prediction in Hardrock Excavation Using

the CERCHAR Abrasiveness Index (CAI), in: Schubert, W.: Rock engineering - theory and

practise, Proceedings of the ISRM regional Symposium EUROCK 2004 & 53rd Geome-

chanics Colloquy: p. 599-604, Essen: Glckauf, 2004.

[17] Plinninger, R.J. & Thuro, K.: Erfahrungen bei Frsvortrieben im Nrnberger U-Bahn-Bau,

Felsbau, 19: p. 1-8, Essen: Glckauf, 2001.

[18] Restner, U.: Sandvik Mining and Constructions Rock Testing Standards 2007, Sandvik

Mining and Construction G.m.b.H., Department of Geotechnical Consulting & Engineering,

Zeltweg, 2007.

[19] Restner, U. & Reumueller, B.: Metro Monreal Successful operation of a state-of-the-

art- rodheader ATM 105-ICUTROC competing with drill & blast operation in urban tun-

nelling, in: Schubert, W.: Rock engineering - theory and practise, Proceedings of the

ISRM regional Symposium EUROCK 2004 & 53rd Geomechanics Colloquy: p. 589-594,

Essen: Glckauf, 2004.:

[20] Rhl, S. & Alber, M.: Die Spannungsabhngigkeit des Cerchar Abrasivittsindex fr unter-

schiedliche Gesteinstypen Confining pressure dependence of the Cerchar abrasiveness

index for different rock types, in: Otto, F.: Verffentlichungen von der 16. Tagung fr Inge-

nieurgeologie, Bochum, 07.-10. Mrz 2007: P. 209-213, 2007.

[21] Schimazek, J. & Knatz, H.: Der Einfluss des Gesteinsaufbaus auf die Schnitt-

geschwindigkeit und den Meielverschlei von Streckenvortriebsmaschinen.- Glckauf,

106: p. 274-278, Essen: Glckauf, 1970.

[22] Thuro, K. & Brodbeck, F.: Auswertung von TBM-Vortriebsdaten - Erfahrungen aus dem

Erkundungsstollen Schwarzach, Felsbau, 16: p. 8-17, Essen: Glckauf, 1998.

[23] Thuro, K. & Plinninger, R.: Geologisch-geotechnische Grundlagen der Gebirgslsung im

Fels, in: Eichler, K. et. al.: Fels- und Tunnelbau II: p. 112-160, Kontakt und Studium, Band

684, Renningen-Malmsheim: Expert, 2007.

[24] Thuro, K., Singer, J. Ksling, H. Bauer, M.: Soil abrasivity assessment using the LCPC

testing device, Felsbau, 24: p. 37-45, Essen: Glckauf, 2006.

[25] Verhoef, P.N.W.: Wear of rock cutting tools, Rotterdam, Brookfield: Balkema, 1997.


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Authors:

Dipl.-Geol. (Univ.) Dr.rer.nat Ralf J. Plinninger, Dr. Plinninger Geotechnik, Kirchweg 16, D-

94505 Bernried/Germany, Tel. +49 9905/7070-360, Fax: +49 9905/7070-361, email: geotech-

[email protected]

Mag. Uwe Restner, Head of Geotechnical Consulting & Engineering, Sandvik Mining and Con-

struction G.m.b.H., Supply Unit Zeltweg, Alpinestrasse 1, A - 8740 Zeltweg/Austria, Tel. +43

3577/755234, Fax: +43 3577/7559234, email: [email protected]

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