Practical Application of GI Technique Rev 0 HAKI pdf

Bauer Design & Construction Systems

PRACTICAL APPLICATIONS OF GROUND IMPROVEMENT TECHNIQUES

Gavin Chung Regional Manager Senior Manager Bauer South East Asia Pacific Region Bauer (M) Singapore Ground Improvement Division

Indonesian Society of Civil and Structural Engineers (HAKI) 14th December 2013

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CONTENTS

Principles of Ground Improvement

Ground Improvement Techniques

Selection of Techniques

Type of Applications

Liquefaction

Bauer-Betterground Range of Techniques

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PRINCIPLES OF GROUND IMPROVEMENT

Consolidation Techniques that drains and reduction of voids

Inclusion / Reinforcement Techniques that introduce foreign elements to improve in situ soil

Compaction Techniques that densify soil by compaction

Ground improvement methods are used to improve unsuitable subsurface soils and/or to improve the performance of structures or embankments. These methods are used when replacement of the in-situ soils is impractical because of physical limitations, environmental concerns, or other conventional methods are costly. Functions:

Increase bearing capacity, shear, or frictional strength, Increase density, Control deformations, Increase or provide lateral stability, Form seepage cutoffs or fill voids, Transfer embankment loads to more competent layers, and Increase resistance to liquefaction.

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PRINCIPLES OF GROUND IMPROVEMENT

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GROUND IMPROVEMENT TECHNIQUES

Ground Improvement

Consolidation

PVD + Surcharge

Vacuum Consolidation

Stone Column + Surcharge with

or w/o PVD

Reinforcement

Vibro – Stone Column,

Concrete Column

Soil-Cement mix – SCC, CSM, FDC

Grouting

Compaction

Vibro Compaction

Dynamic Compaction

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GROUND IMPROVEMENT TECHNIQUES Category Function Methods

Consolidation Accelerate consolidation , increase shear strength and increase density with time

a. Prefabricated Vertical Drain b. Vacuum Consolidation

Reinforcement

In soft foundation soils, increases shear strength, density, improves resistance to liquefaction and reduce settlements

a. Vibro Stone Columns b. Vibro Concrete Columns c. Dynamic Replacement

Physio-chemical alteration of foundation soils to increase their tensile, compressive, and shear strength; reduce settlement; and to provide lateral stability confinement

a. Soil Cement Mix - Soil Cement Column - Cutter Soil Mix - Full Displacement Column

To form fill voids, increase density, increase tensile and compressive strength

a. Grouting - Permeation, Compaction, Jetting & Compensation

Compaction

Increase instantaneous density, bearing capacity, and frictional strength of granular soils. Reduce settlement and increase resistance to liquefaction

a. Vibro Compaction b. Dynamic Compaction

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SELECTION OF TECHNIQUES

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Step Selection Process

1 Suitability of technique (soil and technique compatible)

2 Technical/Performance compliance

3 Possible damage to adjacent structures

4 Construction time available for ground improvement

5 Cost – (check material availability & compare techniques)

6 Environmental issues influencing the technique

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Soil Description Densification Reinforcement

Gravel and sand <10% silt, no clay

Excellent Very good

Sand - 10% to 20% silt and <2% clay

Very good Very good

Sand - >20% silt and non-plastic silt

Marginal (with large displacement)

Excellent

Clays Not applicable Excellent

Example of selection with Stone Column

Treatment depth of vibro stone column can be up to 30m

Example of selection with Vibro Compaction Soil Description Densification

Well graded sand <5% silt, no clay Excellent

Uniform fine to medium sand with <5% silt and no clay

Good

Silty sand with 5% to 10% silt and no clay

Moderate

Silty sand > 10% and >2% clay Not applicable

Clays Not applicable

Treatment depth of vibro compaction column have been done up to 70m (Lausitz, Germany 1999 by Degen family inventor of vibroflot) Limited improvement in silts can be achieved with stone backfill. Densification base on 70% relative density

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EFFECT Accelerate settlement

Reduce settlement

Increase instantly Stability

Mitigate soil liquefaction

PVD, Vacuum + - - - PVD & Preloading + + - -

Columns + + + + Columns & Preloading + ++ + +

Columns & Preload &PVD

++ ++ + +

Soil Mixing n.a. +++ ++ + Jet Grouting n.a. +++ ++ +

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Information Required For Design Selection Geotechnical report (consist of soil investigation report with location of SI shown with footprint of structures), laboratory test such as soil classification, plastic index, undrained shear strength Cu values or friction angles, consolidation test ie Oedometer, SPT, CPT, Vane Shear, boreholes, ground water table etc. Plan view & cross section of the project Specification for geotechnical solutions Design loads – infrastructure and adjacent buildings Load bearings of structures and drawings of the dimension of structures Engineering performance/design criteria and seismic design requirement, if any Standards and codes expected to follow Design reports for foundation and ground improvement Construction time frame and expected commencement for the ground engineering works. The time allowance is critical in determining a cost effective proposal. For projects involving mitigation of earthquake induced settlements and lateral spreading: Mw, Moment Magnitude and PGA, Peak Ground Acceleration datas required.

The above information is crucial to check the 3 main elements for any ground improvement design: a. Settlement b. Stability c. Liquefaction

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TYPE OF APPLICATIONS Infrastructure: Energy Industrial Cut-Off Wall Retaining Wall Embankments Airports Highways Reclamations Low Rise Buildings

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LIQUEFACTION What is “Soil Liquefaction” ?

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LIQUEFACTION Earthquakes with Magnitude > 5 between 2000 and 2008

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Effects of liquefaction – Niigata, Japan LIQUEFACTION

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Bearing capacity failure, Izmit, Turkey. Aug 17th, 1999, M 7.4

Liquefaction – What does it do if not controlled?

LIQUEFACTION

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LIQUEFACTION

Liquefaction – What happens to uncompacted soil

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Prediction of Earthquakes?

Globally a Magnitude 6 earthquake happens once a week, Magnitude 5 ≈ 10 times , 4 ≈ 100 times, 3 ≈ 1000 times.

These quakes happen often in uninhabited locations and then generate little or no damage.

The main damage by earthquakes originates from large quakes of a size that only happens a few times in a century.

Per today we are not able to predict location, time, and magnitude of future earthquake events.

This has to do with the fact that in contrast to weather phenomena, the phenomena generating earthquakes occur mainly underground , hidden from direct observation.

The best insight is gained from recording annual movements on the fault lines and from recording the small-earthquake activity.

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Propagation of earthquake waves (Distance approx. 350 km)

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Loma Prieta earthquake, San Francisco Bay 1989

Liquefaction Computer Simulation with FLAC

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Loma Prieta Earthquake 1989

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LIQUEFACTION MITIGATION

Increase strength ( CRR) Ground improvement (densification or

grouting) Decrease exertion stress ( CSR)

Shear reinforcement with ‘stiffer’ elements within soil mass

Decrease excess pore pressure quickly Reduce drainage path distance with tightly

spaced drains

“What to do?”

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Stone Columns act as vertical drains, thus

reducing the excess pore pressures that lead to

liquefaction.

The earthquake induced shear stress τ is distributed

onto soil and column in a ratio proportional to the stiffness ratio

between both materials.

LIQUEFACTION MITIGATION

Liquefaction prevention by Stone Columns

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BAUER-BETTERGROUND TECHNIQUES

Improvement by Consolidation

Improvement by Inclusion/Reinforcement

Improvement By Compaction

Prefabricated Vertical Drain

Vibro Stone Column Cutter Soil Mix

Soil Cement Column

Vibro Concrete Column

Full Displacement Column

Grouting

Vibro Compaction Dynamic Compaction

Dynamic Replacement

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IMPROVEMENT BY CONSOLIDATION


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PREFABRICATED VERTICAL DRAIN

Joint Operation

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IMPROVEMENT BY INCLUSION/REINFORCEMENT


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VIBRO STONE COLUMN

Vibro Replacement (Wet Top Feed Method)

Vibro Displacement (Dry Bottom Feed Method)

Marine Vibro Stone Column (Dry Bottom Feed Method)

Joint Operation

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VR – Vibro Replacement

VD – Vibro Displacement

Applications of Vibro Technique

VC – Vibro Compaction

Joint Operation

Vibro Technique

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VIBRO STONE COLUMN

Joint Operation

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VIBRO STONE COLUMN Vibro Replacement

Joint Operation

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VIBRO STONE COLUMN

Joint Operation

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Vibro Displacement

VIBRO STONE COLUMN

Joint Operation

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VIBRO STONE COLUMN Vibro Displacement

Bucket Feed System suspended from crane

Excavator Mounted Bottom Feed

Gravel Pump Feed System suspended from crane

Joint Operation

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VIBRO STONE COLUMN Marine Stone Column (bottom feed system)

Joint Operation

Pressure Chamber Injection System (Double Lock Gate)

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TR13 TR17 TR85 Excentrical Moment 13 Nm 17Nm 85Nm

Rotation Speed 3250 min-1

= 54Hz3250 min-1

= 54Hz1900 min-1

= 31Hz Centrifugal Force 150kN 193kN 295kN Amplitude: at Excenter +2.3mm +3.4mm +7.5mm

at Tig +3.5mm +6.0mm +10.5mm Install Engine Power 96kW 96kW 224kW Hydraulic Power Requirement H180 H180 HD420

118kW 118kW 240kW180l/min 180l/min 380l/min

Vibrator Tip: JointLength 3100mm 3200mm 3900mmWeight 1010kg 1100kg 2100kgDiameter 300mm 300mm 406mm

Follower Tube Weight 200 kg/m 200 kg/m 240 kg/m Diameter 300mm 300mm 406mm Flush Air/Water Air/Water Air/Water

Vibroflot (Bauer)

VIBRO EQUIPMENT

Joint Operation

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Vibroflot (Betterground)

VIBRO EQUIPMENT

Joint Operation

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VIBRO STONE COLUMN 2012: Hong Kong Boundary Crossing Facility

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VIBRO STONE COLUMN

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Airport Height Restriction

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VIBRO STONE COLUMN

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VIBRO CONCRETE COLUMN

VCC Process

Joint Operation

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Data Logger Type (Betterground)

Data Logger Type (Bauer)

QUALITY COTROL (DATA LOGGER)

Joint Operation

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Cutter Soil Mix (CSM)

Joint Operation

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CSM Sequence of Work

Cutter Soil Mix (CSM)

CSM Site Configuration

P 1S 2

P 3

S 4

P 5

S 6

P 7S 8

P 9

S 10

P 11

S 12

P 13

S 14

dia 8,5 m

Ø 8,5m

Joint Operation

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Soil-Cement Mix (Wet Method) with Single Auger

Soil Cement Column (SCC)

Joint Operation

49 Joint Operation

Mixing Tools for Triple Auger

Soil Cement Column (SCC)

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Single elements Wall elements

Grid patterns Block types

Deep Cement Mix Configuration

Joint Operation

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Full Displacement Column (FDC)

Joint Operation

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Permeation Grouting

Permeation grouting – is a process of injection of grout into granular, fissured or fractured ground to produce a solidified mass to support increased load and/or to fill voids and fissures.

Joint Operation

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Compaction Grouting

Drilling to final depth Start grouting from lowest level Gradually lifting the rod Grouting in steps

Compaction grouting – injected to loose soils, homogenous grout bulbs are formed and displace, densify and strengthen the surrounding soil

Joint Operation

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Jet Grouting

Joint Operation

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Compensation Grouting

Compensation grouting – process used to control or reverse the settlement of structures, to induce fractures in the soil thereby causing an expansion to take place counteracting settlement and producing controlled heave.

Joint Operation

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Dynamic Replacement (DR)

Ground reinforcement technique which inclusion such as stone or sand is compacted into the ground

Typical design of 2.5m diameter column with spacing between 4.5m to 6m with depth up to 4m-5m

Increase bearing capacity, stability, drainage path and reduce settlement

Joint Operation

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IMPROVEMENT BY COMPACTION


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Vibro Compaction Vibro compaction applications are use in conditions where existing

cohesionless or slightly cohesive soils can be improve by vibration. The basic principles is that the cohesionless soils can be rearranged by

means of vibration, which requires a combination of high frequency vibration and movement induced by the flushing action of injected water resulting in initial replacement and compression of the surrounding soils.

Densification of granular soils by VC results in: a. Increased bearing capacity of soil b. Reduced foundation settlement c. Increased resistance to liquefaction d. Increased resistance to shear movement

Joint Operation

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Vibro Compaction 3

Process

Joint Operation

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Vibro Compaction 3

Marine Vibro Compaction

Joint Operation

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• compaction by surface impact,

• Typical drop height: 20 - 30 m,

• Typical weight:10 to 30 tons,

• Economic depth reach: 12 m to 15 m. (depending on material)

Dynamic Compaction

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Dynamic Compaction VS Vibro Compaction at Depth

Silt Layer

Joint Operation 62

63 For more info: www.bauer.de/en

Special thanks to Dr. Dradjat Hoedajanto, President of HAKI for giving us the opportunity to make this presentation, the support of Mr. Thomas Domanski, Bauer’s Regional Director and our partner Betterground, Dr. Wilhelm Degen.

Practical Application of GI Technique Rev 0 HAKI pdf

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