Eng. Diego Marchetti29 May 2015www.marchetti-dmt.it

Seismic Flat Dilatometer (SDMT)Working Principle, Equipment, Test Procedure, Results

MiddelfartDenmark

Lab Testing In Situ Testing: SCPT & SDMT

In situ testing : simple, fast, economical,repeatable, provides continuous soil profile,results real time, ..

In Sand :recovering undisturbed samples very difficultand in situ testing is the state-of-practice.

Caution : laboratory is the basis for research

TOO SLOW !

Mayne et al: State-of-the-Art Lecture (Alexandria Egypt 2009)17th Int. Conference on Soil Mechanics and Geotechnical Engineering

SCPT & SDMT fast and convenient tools for everyday investigations

SDMT Equipment

DMT(static)

Seismic(dynamic)

DMT equipment

DMT Flat Dilatometer equipment

BLADE

FLEXIBLEMEMBRANE(D = 60mm)

DMT Test Layout

blade

rods

penetrationmachine

pneumatic-electric cable control box

gas tank(air, nitrogen,etc)

Test Procedure

stop every 20 cm

P0: Lift-off pressure

P1: Pressure for1.1 mm expansion

DMT Equipment (mechanical)

Machines for advancing the DMT andSDMT equipment

Truck Penetrometer (most efficient)

cable exitsfrom rods

Light Penetrometer (most common)

Role of penetration for CPT and DMT

CPT – measurements performed during penetration

at a fix speed of 2 cm / sec (with some tolerance)

DMT – penetration necessary to arrive at next test

depth, without constraint on penetration speed.

Measurements when blade is not moving

High flexibility to advance DMT in the soil

Many ways of advancing the blade

Driven by Spt tripod

Driven by drill rig

Pushed by drill rig Driven or pushed bylight penetrometer

Pushed by a fixed platformPushed from a barge

Drill Rig – downhole Torpedo method

• TORPEDO pre-assembled before test and joined to drill rods

• Cable exits from slot of adaptor and is taped to drill rods

• Drill rods + torpedo inserted at bottom of borehole (then advance 20 cm)

DMT test from Jack-up

Venice lagoon, Italy (MO.SE.) Roskilde Fjord,Frederikssund - Denmark

Seafloor DMT

WATERDEPTH 0 to 100 m - PUSH CAPACITY 5 ton

Max test depth is the depth penetrable with 5 ton push.

6-7 ton ballast(built locally)

Shipped byair (50 Kg)

4 bolts

First Seafloor DMT test: 13 June 2014

First Seafloor DMT test: 13 June 2014

First Seafloor DMT test: 13 June 2014

SEAFLOOR DILATOMETER

Shipped by air (50 Kg)

Seafloor

ballast built locally ballast built locally

Supportanchoredto ballast

SeismicDilatometer

SEAFLOOR DMT (2015 USA – river bed)

2015 April 30th

6.5 ton ballast (steel plate)

5 ton push (max)

Field data and Interpretation of the Results

Field Data

Z(m)

P0

(kPa)P1

(kPa)

0.200.400.600.801.001.20…

220210305310285290…

300310420450380390…

DMT Intermediate parameters

Intermediate ParametersDMT Field Readings

P0

P1

Kd: Horizontal Stress Index

Ed: Dilatometer Modulus

Id: Material Index

DMT Formulae – Interpreted parameters

Intermediate

Parameters

Id

Kd

Ed

Interpreted Geotechnical Parameters

Cu: Undrained Shear Strength

Ko: Earth Pressure Coeff (clay)

OCR: Overconsolidation ratio (clay)

Φ: Safe floor friction angle (sand)

γ : Unit weight and description

M: Constrained Modulus

ID contains information on soil type

Performing DMT, immediately notice that:

p1

CLAY

pp0

SAND

p0

p1

p

SILT falls in between

ID=(p0 -u0)

(p1 -p0)

ID contains information on soil type

SAND

CLAY

KD contains information on stress history

KD is an ‘amplified’ K0, because (p0 - u0)is an ‘amplified’ σ’h, due to penetration

KD =σ’v

(p0 - u0)

p0

DMT

Definition of KD similar to K0:

Very roughly Kd ≈ 4 KoE.g. in NC : Ko ≈ 0.5 and Kd ≈ 2

KD reflects ‘stress history’ (OCR)

Depth

Z

Kd

KD contains information on stress history

2

KD = 2 in NC clay (OCR = 1)

NC

OC

KD > 2 in OC clay (OCR > 1)

KD contains information on stress history

OC Kd > 2

NC Kd͌ 2

Taranto 1987

KD correlated to OCR (clay)

ExperimentalKamei & Iwasaki 1995

TheoreticalFinno 1993

TheoreticalYu 2004

OCR = Kd

1.56

Marchetti 1980 (experimental)0.5

KD correlated to K0 (clay)

Theoretical2004 Yu

ExperimentalMarchetti (1980)

K0 =Kd 0.47

Marchetti 1980 (experimental)1.5

0.6

ED contains information on deformation

Theory of elasticity:

ED = elastic modulus of the horizontal load test performed

by the DMT membrane (D = 60mm, 1.1 mm expansion)

1.1 mm

DMT

ED= 34.7 (P1 -P0)

Gravesen S. "Elastic Semi-Infinite Medium bounded by a Rigid Wall with a CircularHole", Danmarks Tekniske Højskole, No. 11, Copenhagen, 1960, p. 110.

ED not directly usable corrections(penetration,etc)

M obtained from Ed using information onstress history (Kd) and soil type (Id)

ED (DMT modulus)

MConstrained

Modulus

KD (stress history)

ID (soil type)

Definition of M (no ambiguity)

Vertical drained confinedtangent modulus (at σ'vo)

M = Eoed = 1/mv = ∆σ'v / ∆εv (at σ'vo)

M Comparison from DMT and from Oedometer

Norwegian Geotechnical Institute (1986)."In Situ Site Investigation Techniques andinterpretation for offshore practice".Report 40019-28 by S. Lacasse, Fig. 16a,8 Sept 86

ONSOY Clay – NORWAY

Constrained Modulus M (Mpa)

Constrained Modulus M (Mpa)

Tokyo Bay Clay - JAPAN

Iwasaki K, Tsuchiya H., Sakai Y.,Yamamoto Y. (1991) "Applicability of theMarchetti Dilatometer Test to SoftGround in Japan", GEOCOAST '91,Sept. 1991, Yokohama 1/6

Virginia - U.S.A.

Failmezger, 1999

Cu from OCRLadd SHANSEP 77 (SOA TOKYO)

Ladd: best Cu measurement not from TRX UU !!

Using m ≈ 0.8 (Ladd 1977) and (Cu/σ’v)NC ≈ 0.22 (Mesri 1975)

Cu

σ’v OC

=Cu

σ’vNC

OCR m OCR = 0.5 Kd

1.56

Cu = σ’v 0.5 Kd

1.250.22

best Cu from oed OCR Shansep

A.G.I., 10th ECSMFE Firenze 1991Vol. 1, p. 37

Cu at National Site FUCINO – ITALY

different CPT profileaccording to Nc value

(Nc 14-22)

Cu comparisons from DMT and from other tests

Recife - Brazil

Coutinho et al., Atlanta ISC'98 Mekechuk J. (1983). "DMT Use on C.N.Rail Line British Columbia",First Int.Conf. on the Flat Dilatometer,Edmonton, Canada, Feb 83, 50

Skeena Ontario – Canada Tokyo Bay Clay - JAPAN

Iwasaki K, Tsuchiya H., Sakai Y.,Yamamoto Y. (1991) "Applicability of theMarchetti Dilatometer Test to SoftGround in Japan", GEOCOAST '91,Sept. 1991, Yokohama 1/6

Interpretation of Soil Description & Unit weight

I )EQUATION OF THE LINES:

SOIL DESCRIPTION

0.6

Material Index

If PI>50, reduce by 0.1

D

Dil

atom

ete r

Mod

ulus

0.1

and/or

PEAT5

MUD12

10

20

50

( )1.5

0.2 0.5

MUD

A

B

C

0.33

1.6

1.8

1.7

1000

(bar

)E

100

200

D

500

2000

D

0.585

0.6570.694

CLAY

2.05

DC

AB 0.621

m

1.9

SILTY

2.0132.2892.564

1.737

n

E =10(n+m log

3.3

1.7

γ

1

I

2

D

0.8 1.2

1.6

1.7

1.8

5

SAND

2

1.8

1.9

2.15

1.95

1.8

2.1

SILT

CL

AY

EY

SILTY

SA

ND

Y

D

and ESTIMATED γ/γwChart for evaluating:

ɣ unit weight ( σ'vo profile)

Soil description

as f (ID, ED)

Material Index ID

Dila

tom

ete

rM

od

ulu

sE

D(b

ar)

Marchetti & Crapps 1981

Example red dot:

ID = 1.6, Ed = 200 bar

Ɣ = 1.8 Ɣw

Soil description: sandy silt

C-reading

Readings:

ON OFF ON (OFF) ON

P0 P1 C (P2)

Audio signal:

C readings (in sand): pore water pressure

Schmertmann 1988 (DMT Digest No. 10, May 1988, Fig. 3)

SAND: C ≈ Uodrainage (≈ piezometer)

CLAY: C > Uono drainage (≈ highlights ∆u)

Du≈0

Du≈0

Du>0

UD=(p0 -u0)

(p2 -u0)

Example of C readings

Catania Harbour - 2012

Example of C readings

Catania Harbour - 2012

Example of C readings

wedge vs cone (dissipation)

Dissipation test in cohesive soilsestimate coefficient consolidation & permeability

Time (min)

h(k

Pa

)

Totani et al. (1998)

wedgeFrom a ≈ miniembankmentLarger volumein a lessdisturbed zone

coneFrom u(t) ina singularhighlydisturbedpoint

Acquisition DMT Dissipation (T, A)

DMT Dissipation Interpretation (Ch, Kh)

Validation of consolidation coefficientDMT vs. other dissipation tests

Totani et al. ISC '98 - Atlanta, Georgia (USA)

Seismic Dilatometer (2004)

SDMT – Test Layout

Acquisition Board

DM

TS

eis

mic

pro

be

Top Sensor

Bottom Sensor

Shear wave velocity measurement

Hammer generating shear wave

Data Acquisition is rapid (7-8 sec)

Vs interpretation real time

Automatic delay evaluation

Cross-correlation algorithm

shift red signal back

towards blu signal, until

best superimposition is

obtained

Δt = wave delay

SDMT main features

Accuracy of delay (Δt) calculation

• true-interval (2 receivers instead of 1)

• Trigger offset no influence on Δt calculation

• Same wave to both receivers

• Signals are amplified and digitized in depthclean waves delay Δt very clear

• Vs interpretation

• Automatic

• operator independent

• real time

• Test execution is rapid

• no hole

• no wait for cementation (e.g. crosshole, downhole)

SDMT

Fucino-TelespazioNational Research Site

(Italy) 2004

SDMT(2004)

SCPTCross HoleSASW

AGI (1991)

Vs at National Site FUCINO – ITALY

Vs validations

Bothkennar(UK)

Treporti-Venezia(Italia)

Zelazny Most(Polonia)

0

5

10

15

20

25

30

35

40

0 100 200 300 400Vs (m/s)

Z(m

)

SDMT P.I.

SDMT T.I.

SCPT P.I.

SDMT pseudo-intervalSDMT true-intervalSCPTU pseudo-interval

Młynarek et al.(2006)

McGillivray &Mayne (2004)

Hepton(1988)

Soils testable by DMT/SDMT

DMT• ALL SANDS, SILTS, CLAYS• Very soft soils (Cu = 2-4 kPa, M=0.5 MPa)

• Hard soils/Soft Rock (Cu = 1 MPa, M=400 MPa)

• Blade robust (safe push 25 ton)

SDMT• All penetrable soils

• Non penetrable soils (gravel, rock, ..):

inside a backfilled borehole

Max depth: 135 m in L’Aquila (2009)

Vs in non-penetrable soils

Totani (2009)

Method (downhole):

Drill borehole

careful backfill of borehole with

gravel (grains D = 5-15 mm)

Vs in borehole

the sand

travelpath

is similar

Travelpath includes short path in the

sand backfill similar for both receivers

delay Δt does not change

SDMT validation in non-penetrable soils

(only Vs in sandfilled borehole - no DMT !!!)

In penetrable soils both

procedures are possible

results ≈ same

SDMT in borehole (140m) – Aquila (ITALY)

SHEAR WAVE VELOCITY (m/s)Aquila (Earthquake – 2009)Fill Material

Calcareous Breccia

LACUSTRINE DEPOSITS:

SILTY SAND and

CLAYEY-SANDY SILT

De

pth

(m)

Main Applications using SDMT results

SDMT main graph

DMT Seismic DMT

GO= ρ Vs2

grain size stress historycompressibility strength Vs and G0

SDMT repeatability

repeatability ≈ 1-2%

Other SDMT results

OCR (clay)

K0 (clay)

Soil description

Unit weight ɣ (kN/m3)

Friction angle (sand)

Pore water pressure (sand)

Ch and Kh (clay & silt)

Vp (compression wave)

KD indicator of Stress History

KD indicator of stress history

Calibration chamber tests with prestraining cycles

Jamiolkowski & Lo Presti ISC'98 Atlanta

CC TEST N. 216 IN TICINO SAND

Kd increased 7 times the increaseof penetration resistance

Stress History: effects on CPT and DMT

Effect of SH onnormalized Qc (CPT)

Lee 2011, Eng. Geology – CC in sand

Effect of SHon KD (DMT)

Kd more reactive than Qc to Stress History

Stress History may have a very strong impacton settlement and liquefaction huge costsavings, especially in medium-big projects

KD leads to a more economical design

Two sites: same Qc, different OCR. Site 2 much ‘stronger’

Main SDMT applications

Settlements of shallow foundations

In situ G-γ decay curves

Compaction control

Liquefaction risk analysis

Slip surface detection in OC clay

Seismic design (Eurocode 8)

Laterally loaded piles (P-y curves)

Diaphragm walls (springs model)

FEM input parameters (es. Plaxis)

DMT for Settlements

Main DMT Application: Settlement prediction

LOAD

Boussinesq

Δσv

SOIL

DMT

M

ƩS =Δσv

MΔz

1-D approach (classic Terzaghi)

Many publications & case histories ofgood agreement between measured andDMT-predicted settlements / moduli:

• Vargas (2009)

• Bullock (2008)

• Monaco (2006)

• Lehane & Fahey (2004)

• Mayne (2001, 2004)

• Failmezger (1999, 2000, 2001)

• Crapps & Law Engineering (2001)

• Tice & Knott (2000)

• Woodward (1993)

• Iwasaki et al. (1991)

• Hayes (1990)

• Mayne & Frost (1988)

• Schmertmann 1986,1988)

• Steiner (1994)

• Leonards (1988)

• Lacasse (1986)

…

…

Observed vs. predicted by DMTSilos on Danube Bank (Belgrade )

DMT Settlement prediction: 77 cmMeasured Settlement: 63 cmDMT +22%

D. Berisavijevic, 2013

Observed vs. predicted by DMTDormitory Building 13 storeys (Atlanta - USA)

DMT

observed

Settlements profile: Measured vs DMT predicted

(Piedmont residual soil)

Mayne, 2005

SPT Settlement prediction: 460 mm

DMT Settlement prediction: 250 mm

Observed Settlement: 250 mm

SPT large error conservative expensive !!!

M at Sunshine Skyway BridgeTampa Bay – Florida

World record span for cablestayed post-tensioned concretebox girder concrete construction

(Schmertmann – Asce Civil Engineering – March 1988)

M from DMT ≈ 200 MPa (≈ 1000 DMT data points)M from laboratory: M ≈ 50 MPaM from observed settlements: M ≈ 240 MPa DMT good estimate of M

DMT Settlements software

Settlement prediction using DMT Settlements

software from the Constrained Modulus obtained

with the Flat Dilatometer in Bogotà two weeks

ago (May 9th) in a 30 m SDMT test lasted 4 hours

SDMT Escuela Colombiana 9 May 2015

SDMT Escuela Colombiana 9 May 2015

SDMT Escuela Colombiana 9 May 2015

SDMT Escuela Colombiana 9 May 2015

SDMT Escuela Colombiana 9 May 2015

SDMT Escuela Colombiana 9 May 2015

SDMT Escuela Colombiana 9 May 2015

Possible reasons DMT good settlement predictions

Baligh & Scott (1975)

measure zone

measurezone

Stiffness ≠ Strength

2. Modulus by mini load test relates betterto modulus than penetration resistance

1. Wedges deform soil less than cones

Possible reasons DMT predicts well settlement

Mayne(2001)

Soil is loaded at strain level for deformation analysis

Go and MDMT on the G - γ decay curve

G0 / MDMT may provide an estimate of in situ G-γ decay curve- Amoroso et al (2014, 2012)

- Marchetti et al (2008) in Schmertmann Volume

- Lehane & Fahey (2004) Porto ISC-2 – non linear settlement analysis from in situ tests

HARA (1973)

YOKOTA et al. (1981)

TATSUOKA (1977)

SEED & IDRISS (1970)

ATHANASOPOULOS (1995)

CARRUBBA & MAUGERI (1988)

0.05 to 0.1%

HARA (1973)

YOKOTA et al. (1981)

TATSUOKA (1977)

SEED & IDRISS (1970)

ATHANASOPOULOS (1995)

CARRUBBA & MAUGERI (1988)

0.05 – 0.1%

Maugeri (1995)

Mayne (2001)Ishihara (2001)

SDMT G0 - small strain modulus

MDMT - working strain modulus (γ = 0.05 – 0.1 %)two points

low GO/M

high GO/M

0

0.2

0.4

0.6

0.8

1

1.2

0.0001 0.001 0.01 0.1 1 10

no

rma

lized

sh

ea

rm

od

ulu

s,G

/G0

shear strain,g (%)

GDMT/G0 sand:gDMT ≈ 0.015 - 0.30 %

GDMT/G0 silt and clay:gDMT ≈ 0.23 - 1.75 %

G0 (Vs) from SDMT

1.2Sands (Darendeli2001)

Silts and clays with PI=0-50%(Darendeli2001)

Silts and clays with PI=50-100%Darendeli (2001)

Sands (experimentaldata)Silts and clays (experimentaldata)

"typical shape" G/G0-γcurves in different soiltypes

range of values of GDMT/G0 andcorresponding shear strain γDMT determinedby the "intersection" procedure in differentsoil types

G - γ decay curve: experimental results

(Amoroso et al. 2012, 2014)

SDMT experimental data usedto assist the construction of ahyperbolic equation

Summary of results

(Amoroso et al. 2014)

Comparison betweenhyperbolic and "measured"stiffness decay curves

DMTDMTG

GG

G

γ

γ

−+

=

11

1

00

0

0.2

0.4

0.6

0.8

1

1.2

0.0001 0.001 0.01 0.1 1 10

DSDSS - Roio Piano S3 C2

GDMT/G0 Roio Piano S3 C2

Hyperbolic curve

ROIO PIANOClayey silt(b)

no

rmal

ize

dsh

ear

mo

du

lus,

G/G

0

shear strain,g (%)

Compaction Control

DMT for Compaction Control

The high sensitivity to changes of stresses and density make the DMT particularly

suitable for detecting benefits of SOIL IMPROVEMENT

Compaction of a loose sandfillResonant vibrocompaction technique

Van Impe, De Cock, Massarsch, MengéNew Delhi (1994)

Dep

th(m

)

DMT vs CPT sensitivity to Compaction

Schmertmann (1986) DYNAMIC COMPACTION of sand site.MDMT % increase ≈ twice % increase in Qc

Jendeby (1992) monitored DEEP COMPACTION in a sand fillby VIBROWING. MDMT increase ≈ twice increase in Qc.

Pasqualini & Rosi (1993) VIBROFLOTATION job :

"DMT clearly detected improvement even in layers wherebenefits were undetected by CPT".

Ghent group (1993) before-after CPTs DMTs to evaluateeffects (±∆σh , Dr) by PILE (Atlas) INSTALLATION"DMTs before-after installation demonstrate more clearly

[than CPT] beneficial effects of Atlas installation".

Compaction Control DMT vs CPT

Jendeby 92: Qc & Mdmt before & after compaction of a loose sandfill

Before compaction

After compaction

Subgrade Compaction Control

MDMT acceptance profile(max always found at 25-26 cm)

Bangladesh Subgrade Compaction Case History90 km Road Rehabilitation Project

Acceptance MDMT profile fixed and used asalternative/fast acceptance tool for quality control ofsubgrade compaction, with only occasional verificationsby originally specified methods (Proctor, CBR, plate),(Marchetti, 1994)

DMT for Liquefaction Risk Assessment

Liquefaction risk assessment

Robertson & Wride (1998) CRR by CPT adequate for low-risk projects. For high-risk: estimate CRR by more than onemethod

Youd & Idriss (NCEER Workshops 2001) use 2 or moretests for a more reliable evaluation of CRR

Idriss & Boulanger (2004) the allure of relying on a singleapproach (e.g. CPT-only) should be avoided

Jamiolkowski (1985, 11 ICSMFE) reliable predictions ofCRR require the development of some new in situ device[other than CPT or SPT] much more sensitive to theeffects of past stress and strain histories

VERY CAUTIOUS RECOMMENDATIONS USING SPT AND CPT

Basis of the correlation CRR-KD

Research has pointed out:

KD sensitive to stress history (including aging),cementation, structure …

KD correlated with relative density and in situstate parameter

all factors known to influence liquefaction resistance

KD ≈ Stress History Index ≈"cumulative" index

parameter of liquefaction resistance

Horizontal Stress Index KD = (p0- u0) /σ'v0

Summary of CRR-KD correlations(Seed & Idriss 1971 simplified procedure)

MAGNITUDE M = 7.5 – CLEAN SAND

SDMT for LIQUEFACTION

SDMT provides 2 independent evaluations of CRR

Andrus & Stokoe (2000)Andrus et al. (2004)

CRR from VsCRR from KD

Marchetti ASCE 2013

... good to have more than one method for CRR …

SDMT for LIQUEFACTIONVittorito – L’Aquila (April 2009)

Kd

Vs

Moment magnitude MW: 6.3Distance from the epicentre: 45 kmPeak ground acceleration PGA: 0.065 g

CSR

SDMT for LIQUEFACTION

Liquefaction depth from Vs: 1-2.5 m

0

0.1

0.2

0.3

0.4

0.5

0.6

0 50 100 150 200 250

Normalized shear wave velocity, Vs1 (m/s)C

yclic

Str

ess

Ra

tio

,C

SR

or

Cyc

licR

esis

tan

ce

Ra

tio

,C

RR

Fc <=5%

Fc= 15%

Fc >= 35%

LIQUEFACTION

NOLIQUEFACTION

Monaco et al. (2009, 2010)

Liquefaction depth from KD: 2-6 m

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10

Cyc

licS

tress

Ra

tioC

SR

or

Cyc

licR

esi

stance

Ratio

CR

R

KD

LIQUEFACTION

NO LIQUEFACTION

Both Kd and Vs indicated Liquefaction (red points)

Liquefaction case history in Costarica

“Just a few weeks after the SDMT execution, the cyclic wave action dueto a storm induced liquefaction of the soil deposit..” (Vargas & Coto 2012)

cofferdam

Design Earthquake (M Richter = 7,5 and PGA = 0,25 g)

LIQUEFACTION

NO LIQUEFACTION

LIQUEFACTION

NO LIQUEFACTION

Slip surface detection in OC clay slopes

(Totani et al. 1997)

DMT-KD method Verify if an OC clay slopecontains active (or old quiescent) slip surfaces

Validation of DMT-KD methodLANDSLIDE "FILIPPONE" (Chieti)

LANDSLIDE "CAVE VECCHIE" (S. Barbara)

DOCUMENTEDSLIP SURFACE

DOCUMENTEDSLIP SURFACE(inclinometers)

Slip surface detection in clay slopes

SS. N. 83 “Marsicana”Gioia dei Marsi (2006)

blocked

Mine of lignite S. Barbara(San Giovanni Valdarno)

Quantify σ'h relaxation behind a landslide

Case History:Landslide in Milazzo, Sicily

Horizontal Stress σ’h(kPa)

Z(m

)–

above

sea

leve

l 1

2

3

σ’h obtained using K0 from DMT

RAILWAY

123

clay

Design of Laterally Loaded Piles

Design of laterally loaded piles (Winkler)

Three different methods using DMTresults for evaluating P-y curves forlaterally loaded piles:

Es = constant

Deflection yS

oil

rea

ctio

n,

p

Linear P-y curve

Es = f (y)

Deflection y

So

ilre

actio

n,

p

Non Linear P-y curve

Gabr & Borden (1988)

Robertson et al. (1989)

Marchetti et al. (1991)

recommendedmethods

Robertson et al. (1989)

Marchetti et al. (1991)

Observed vs. DMT predicted pile deflections

single pile, 1st time monotonic loading In clay.L=57m, D=0.50m

Mortaiolo (Italy)

NC soft clay

Mortaiolo (Italy)

NC soft clay

Validation:2 independent methodsusing DMT results(Robertson 1989 &Marchetti 1991) providesimilar predictions, invery good agreementwith measured full-scalepile behaviour

(1989)

Design of Diaphragm Walls

DMT for DESIGN of DIAPHRAGM WALLS

Tentative correlation forderiving the Winkler modelsprings for design of multi-propped diaphragm wallsfrom MDMT

Indications on input modulifor FEM analyses (PLAXISHardening Soil model) basedon MDMT

g.l.

sH

L

g.l.g.l.

ssHH

LL

Monaco & Marchetti (2004 – ISC'2 Porto)

DMT for FEM input parameters→ PLAXIS Hardening Soil constitutive model

E50ref is a reference stiffness

modulus corresponding to thereference confining pressurepref (pref =1 bar)

E50 is the Modulus for primary loading

Eurref =4⋅Eoed

ref = 4⋅MDMT

(Vermeer, 2001)

E50ref correlated to MDMT and Eoed

ref

(Schanz & Vermeer, 1997)

literature: E50ref = 15 to 75 MPa, like

MDMT by DMT (quartz sand, loose

to very dense sand)

E50ref = Eoed

ref = MDMT

Some SDMT test sites...

Via Fori Imperiali Piazza Venezia

Underground in Rome - New Line C

Palazzo Esposizioni - Rome

This building experienced acrack in the ceiling due todifferential settlements

SDMT 1 (front) SDMT 2 (front) SDMT 3 (back)

CROSS SECTION: CONSTRAINED MODULUS M (MPa)

SDMT - NASA Cape Kennedy (USA)

SDMT at Zelazny Most – PolandTests performed for monitoring copper waste dam

DMT users community

Major diffusion: North-America, Europe, Eastern Asia

Expanding in: South America and Australia

STANDARDSEUROCODE 7 (2007). Standard Test Method, European Committee forStandardization, Part 3: Design Assisted by Field Testing, Section 9: FlatDilatometer Test (DMT), 9 pp.

ASTM (2007). Standard Test Method D6635-01, American Society for Testingand Materials. The standard test method for performing the Flat DilatometerTest (DMT), 14 pp.

TC16 (1997). “The DMT in soil Investigations”, a report by the ISSMGETechnical Committee tc16 on Ground Property, Characterization from in-situtesting, 41 pp.

ASTM (2011) – Standard Test Method D7400 – 08, “Standard Test Methods forDownhole Seismic Testing“, 11 pp.

NATIONAL STANDARDS:

• Italy: Consiglio Superiore Lavori Pubblici (2009), Protezione Civile (2008)

• Sweden: Swedish Geotechnical Society SGF report (1994)

• France: ISO/TS 22476-11:2005(F)

• China: TB10018 (2003), GB50021 (2003), DGJ08-37 (2012)• ..

Website: www.marchetti-dmt.it

3rd International Conference on theFlat Dilatometer (DMT)

Rome 14th-16th June 2015

Official web site:

www.dmt15.com

Papers:

papers@dmt15.com

Contact Info:

info@dmt15.com

Highlights of the conference include

Prof. Roger Frank (ISSMGE president) Welcomespeech

Prof. J. Schmertmann’s dinner talk

Prof. M. Jamiolkowski: use of SDMT in theZelazny Most dam in Poland

Prof. F. Schnaid: use of DMT and SDMT in

tailings dam

120 abstracts from over 32 countries

www.dmt15.com

Conference venue in the town centerwww.dmt15.com

Rome Touristic Attractionswww.dmt15.com

St. Peters and Pope Francescowww.dmt15.com