Improvement of granular soilsImprovement of granular soilsDesign aspects, execution,Design aspects, execution,

monitoring and quality controlmonitoring and quality control

Rainer Massarsch Rainer Massarsch Geo Engineering ABGeo Engineering AB

GEOTEKNIKERDAG 2007GEOTEKNIKERDAG 2007GrundforbedringGrundforbedring -- Session A3:Session A3:

Objectives of deep soil Objectives of deep soil compactioncompaction

Bearing capacity of foundations, stability of slopes Bearing capacity of foundations, stability of slopes excavations ( static and/or dynamic)excavations ( static and/or dynamic)SettlementsSettlements (total (total & & differential deformations)differential deformations)Lateral earth pressure against retaining structuresLateral earth pressure against retaining structuresLiquefaction hazard due to dynamic and cyclic Liquefaction hazard due to dynamic and cyclic loading (e.g. caused by earthquakes)loading (e.g. caused by earthquakes)Soil permeabilitySoil permeabilityGeneral improvement of heterogeneous soil depositsGeneral improvement of heterogeneous soil deposits

Recent DevelopmentsRecent DevelopmentsAvailability of powerful construction equipmentAvailability of powerful construction equipment

Reliable and accurate field investigation Reliable and accurate field investigation methods methods

Better understanding of the static and dynamic Better understanding of the static and dynamic stressstress--strain behaviour of soilsstrain behaviour of soils

Advanced analytical tools for geotechnical Advanced analytical tools for geotechnical analysis and designanalysis and design

Increasing awareness of seismic effects on Increasing awareness of seismic effects on foundations foundations

Reliable electronic measuring systemsReliable electronic measuring systems

Design ConsiderationsDesign ConsiderationsCCompaction energy at each compaction pointompaction energy at each compaction pointSpacing between compaction pointsSpacing between compaction pointsDuration of compaction in each point Duration of compaction in each point Ground settlements due to compaction Ground settlements due to compaction Time interval between compaction passes Time interval between compaction passes Verification of the achieved compaction effect Verification of the achieved compaction effect CCompaction effect with time after compactionompaction effect with time after compactionGround vibrations in the vicinity Ground vibrations in the vicinity SStabilitytability of nearby slopes or excavations of nearby slopes or excavations Monitoring of equipment performanceMonitoring of equipment performance

Classification of Soil Classification of Soil Compaction MethodsCompaction Methods

Energy transfer from ground surface:Energy transfer from ground surface:Impact:Impact: Dynamic Compaction, Impact RollerVibratoryVibratory:: Vibratory Plate

Energy transfer below ground surface:Energy transfer below ground surface:ImpactImpact:: Driven probe/pile, Driven stone column

ExplosivesVibratoryVibratory:: Vibroflotation, Vibratory probes,

Resonance compaction

Energy applied at Ground SurfaceEnergy applied at Ground Surface

••Dynamic CompactionDynamic Compaction

••Impact RollerImpact Roller

••Vibratory PlateVibratory Plate

Energy Transfer below Ground Energy Transfer below Ground SurfaceSurface

ResonaceResonace CompactionCompaction

VibroflotationVibroflotation

ExplosivesExplosives

Displacement Pile Method Displacement Pile Method

Driven stone columnDriven stone column

VibroVibro--Probes Probes

Dynamic CompactionDynamic Compaction

Sand ColumnsSand Columns

Stone Column MethodsStone Column Methods

VibroflotationVibroflotation

VibroVibro--Replacement ColumnsReplacement Columns

Stone Columns Stone Columns -- VibroflotationVibroflotation

VibroVibro--Compaction ProbesCompaction Probes

VibrocompactionVibrocompaction -- VibroWingVibroWing

Soil Investigation MethodsSoil Investigation MethodsPlanning phasePlanning phase of a project for establishing of of a project for establishing of geotechnical conditionsgeotechnical conditionsDesign phaseDesign phase for selection of appropriate for selection of appropriate compaction methodcompaction methodTrial phaseTrial phase for evaluation of compaction for evaluation of compaction procedure and verification procedure and verification Production phaseProduction phase for production control for production control compaction effect compaction effect CompletionCompletion of the project for documentation of of the project for documentation of longlong--term performanceterm performance

Soil Investigation MethodsSoil Investigation Methods

Standard Penetration Test (SPT)Standard Penetration Test (SPT)

Cone Penetration Tests (CPT)Cone Penetration Tests (CPT)

Pressuremeter Test (PMT)Pressuremeter Test (PMT)

Dilatometer Test (DMT)Dilatometer Test (DMT)

Seismic testsSeismic tests

Results of CPTU TestResults of CPTU Test

Results of CPTU TestResults of CPTU Test

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 5 10 15 20

CONE STRESS (MPa)

DE

PTH

(m

)0

1

2

3

4

5

6

7

8

9

10

0 10 20 30 40 50

SLEEVE FRICTION (KPa)

DE

PTH

(m

)

AFTER

BEFORE

BEFORE

AFTER

CompactibilityCompactibility of Soils base on CPTof Soils base on CPT

1

10

100

0 0,5 1 1,5 2 2,5 3

FRICTION RATIO, %

CO

NE

PEN

ETR

ATI

ON

RES

ISTA

NC

E, M

Pa

compactable notcompactable

marginally compactable

Settlement EstimationSettlement EstimationTangent Modulus MethodTangent Modulus Method

Correlation of soil modulus with stressCorrelation of soil modulus with stress--adjusted cone resistance adjusted cone resistance

⎥⎦

⎤⎢⎣

⎡ ′−

′⎟⎠⎞

⎜⎝⎛=

rrm σσ

σσε 012

( )j

r

vrt m

ddM

−

⎟⎟⎠

⎞⎜⎜⎝

⎛ ′==

1

σσ

σεσ

Soil Type Correction factor, aSilt, organic soft 7 Silt, loose 12 Silt, medium dense 15 Silt, dense 20 Sand, silty loose 20 Sand, loose 22 Sand, compact 28 Sand, dense 35 Gravel, loose 35 Gravel, dense 45

r

Mqamσ

=

MarchettiMarchetti DilatormeterDilatormeter

Effective StressC

ompr

essi

on

Over-consolidated

Normally consolidated

Increase in stiffness

M

Soil Compaction causes Overconsolidation!

IncreaseIncrease of of SoilSoil StiffnessStiffness & & PrePre--consolidationconsolidation

Compaction

VibratoryVibratory--installed Soil Nailsinstalled Soil NailsHalle, GermanyHalle, Germany

Increasedconfiningstress aroundnails

Q

Load fromnails

Load fromfooting

9000

150

500

200

φ 180

200

0

0,5

1

1,5

2

2,5

0 50 100 150 200 250 300 350

LOAD, kN

DEF

OR

MA

TIO

N, m

m

Stell tube

Concrete Nail

ResultsResults of of LoadLoad --testingtesting

Thank you for your attention!Thank you for your attention!