CQC-CQA procedures for different materials (EuroGeo5) · • number of samples: according the...

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COURSE B

QUALITY ASSURANCE AND CONTROL OF

GEOSYNTHETICS IN LANDFILL APPLICATION

Madalena Barroso

CQC/CQA procedures (observations, tests, testing frequencies, corrective actions and documentation) for different materials

Outline

• Aims

• Background

• CQC/CQA activities

• Summary

Aims

• Introduce the main QC/CA activities to be

performed to assure that the geosynthetic

processes, to be used in the landfill, conform

to the specifications

• Discuss the major issue to take into

consideration to ensure the quality of

installation of geosynthetics

2

Background

CQA Plan: aims to ensure that the geosynthetic materials

and workmanship meet design specifications

� responsabilities of all staff involved in the construction

� documents/reports to be prepared to evidence the quality of construction

�sets out in detail the QC/QA activities

Background

Waste

Compacted Clay Liner

Geotextile filter

GeomembraneGeotextile protection

GCL

Pipes Primary leachate collection

Typical section for the geosynthetic lining system of a municipal

solid waste landfill (non-hazardous landfill)

Background

Polymers Abbreviation Type of compoundHigh density polyethylene HDPE Thermoplastic

Low density polyethylene LDPE Thermoplastic

Very low density polyethylene VLDPE Thermoplastic

Linear low density polyethylene LLDPE Thermoplastic

Polypropylene PP Thermoplastic

Ethylene propylene diene monomer EPDM Thermoset

Chlorinated polyethylene CPE Thermoplastic/thermoset

Polyvinyl chloride PVC Thermoplastic

Chlorosulfonated polyethylene CSPE Thermoplastic/ thermoset

Ethylene interpolymer alloy EIA Thermoplastic

3

CQC/CQA activities

• Acceptance/receipt of materials

• Storage

• Transport and handling

• Installation (observations, tests, testing

frequencies, corrective actions, etc.)

• Leak detection

Geomembrane

Similar activities for other geosynthetics!

CQC/CQA activitiesAcceptance/receipt of materials

• Review the information from manufacturer (CE-accompanying

documents, producer’s manufacturer quality control, producer’s roll

data reports, producer’s certification- if available-, etc.)

• identification of the rolls (producer, brand, product type,

roll-weight, dimensions, mass per unit area, raw material-, etc.),

CE-marking affixed, marking of product name in accordance with

the purchase order and delivery note

• Conformance testing for evaluation of the compliance of a delivered

product with the design specification

CEN/TR 15019 (2005) - Geotextile and geotextile-related products: On-site quality control

• Is correct product delivered to site?

• Does the product meet design specifications?

CQC/CQA activitiesAcceptance/receipt of materials

Conformance testing

• independent laboratory

• priory installation

• tests to be performed shall include all relevant properties to the performance of geosynthetic

• number of samples: according the design specification

CEN/TR 15019:

• safety level high applications: 1 sample/30 000m2, with a minimum 1 test above 1 000 m2

• safety level normal applications: 1 sample/50 000m2, with a minimum 1 test above 10 000 m2

All specimens shall pass for all tested properties !

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CQC/CQA activitiesStorage

CQC/CQA activitiesStorage

CQC/CQA activities

Transport and handling

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CQC/CQA activitiesTransport and handling

CQC/CQA activitiesInstallation

� Surface preparation

� Anchor trench

� Panel placement

� Seams

� Seam testing

� Protection of geomembrane



� Anchor trench

� Panel placement

� Seams

� Seam testing


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Surface preparation| side slopes


Surface preparation| side slopes


Surface preparation| bottom

Design specifications may require Wopt. (optimum water content)

to be between 2 and +4 % points of Wopt. (lowest hydraulic

conductivity)

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� Anchor trench

� Panel placement

� Seams

� Seam testing



Anchor trench

20IGS-Brasil (2003)

Geomembrane

Fill material

Must be properly designed!


Anchor trench

rounded

8


Anchor trench

22


Anchor trench

Inadequate construction practices (insufficient weight at anchor trench)

Temperature effect

Wrinkles at the toe of slope



� Anchor trench

� Panel placement

� Seams

� Seam testing


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Panel placement

• Layout (Panel Installation Plan) shall covers the needed boundaries

• Layout shows the planned placement sequence of the panels and the

locations of all special features

• Seam type and lap has must be identified on the layout and shall

conform to the specifications

• Seams shall be oriented as addressed in the specifications (on slopes,

seams shall be parallel to the slope gradient)

• “T” seams will be prepared in the approved manner (spacing > 0.5 m)

• Layout shall formally be accepted when complete and accurate

Panel numbering system and seam numbering system shall be in agreement

(shall have correspondence between panel numbers, seam numbers, roll

numbers, test locations, repair locations, and other information)


Panel placement |corners

26

> 0,5 m

B = panel width

slopes > 15 m

slopes < 15 m

GM without support

(“trampoline”)!

Evitar

remendos em

cruz

≥0,5 m

≥0,5 m

≥0,5 m

≥0,5 m

Cross seams

shall be avoided

Toe of slope Panel at base

Seam

Toe of slope

Top of slope


Panel placement |slopes

Panels placed in curve:

• seams parallel to the slope gradient

• unwrinkled panels

≥ 0,5 m

≥ 1,5 m

B = panel width

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Panel placement |horizontal seams

horizontal seams

horizontal seams


Panel placement |Overlaps

Soldadura

horizontal

Flow

Flow

Overlaps

Overlaps


Panel placement |wind

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Panel placement |wind



� Anchor trench

� Panel placement

� Seams

� Seam testing



Seams | seaming methods

Type of

geomembrane

Seaming methodExtrusion

(fillet and flat)

Thermal fusion

(hot wedge and hot air)

Chemical fusion

(chemical and bodied)

Adhesive

(chemical and contact)

HDPE √ √

VLDPE √ √

PP √

PVC √ √ √

CSPE-R √ √ √

EIA-R √ √ √

R = reinforced

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Seams | seaming methods (HDPE)

Extrusion150 mm

25 a 40 mm

Extrusion

T = Thickness

Top geomembrane

Bottom geomembrane

inferior

Thermal fusion (dual hot wedge)


Seams | Trial seams

Aim to reproduce all aspects of the actual field seaming activities

intended to be carried out in the immediately upcoming

geomembrane installation, to confirm equipment and operator

proficiency

• Used for all routine destructive seam testing for seam strength

evaluation

• Tests are typically made at beginning of the work shift and after

lunch break; after each interruption of work; whenever personal

or equipment are changed; and weather conditions dictate

• Field seaming only allowed when the test results pass


Seams | production seaming

� The area to be seamed is clean, dry and without folds or wrinkles

� Seams are not made below 10°C or above 40°C

� Seams are not made at night, with rain, excessive humidity or wind

� Overlaps between the panels meet the design specifications and /or the

manufacturer's recommendations

� No solvent or adhesive are used in the seam area

� On slopes, seams are parallel to the slope gradient

� There is no horizontal seam less than 1.5 m from the toe of the slope or in areas

where large concentrations are predictable

� At the corners, or places of complicated geometry, the number of seams shall be

minimized

� All seams are identified (at seam and at layout)

� Equipment used does damage the geomembrane

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� Anchor trench

� Panel placement

� Seams

� Seam testing


• Destructive tests | relative strength of the seams

(according the frequency defined in project

specifications)

• Non-destructive tests| seams continuity (over

100% of the seams)

Seams need to be both fluid-tight and to have a

strength of the same order of magnitude as

geomembrane panels

Seam testing



Seam testing | detructive tests

�Peel test | evaluate the adhesion strength between

two seamed geomembranes or between the extruded

polymer and the sheets

�Shear test | assess how the seaming process affects

the strength of the adjacent geomembrane

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Seam testing | detructive tests | peel test (ASTM D 6392)


Seam testing | detructive tests | shear test (ASTM D 6392)

• Peel test

– peel strength

– peel separation

– locus-of-break pattern

• Shear test

– shear strength

– shear elongation

– locus-of-break pattern


Seam testing | destructive tests | test results (ASTM D 6392)

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Seam testing | destructive tests | test results |locus-of-break patterns

Per their description in ASTM D 6392


GRI-GM 19 Seam Specification provides

required seam strength and related properties

for accept/reject HDPE GM seams

Seam testing | destructive tests | acceptance criteria

Seam Test PropertyMinimum/maximum properties values

(HDPE geomembranes, 2.0 mm)

Dual hot wedge

peel

strength 72 % of the tensile GM yield strength

separation ≤ 25%

unacceptable break codes*

shear


elongation at break ≥ 50 %

unnacceptable break codes*

Extrusion

peel


separation ≤ 25%


shear


elongation at break ≥ 50 %



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Seam testing | destructive tests | sampling and testing frequency

Testing frequency: GRI-GM 19 recommends 1 sample per 150 m

of seam length; must be flexible, depending on the quality

Sampling: suspected seams/local

1 LABORATÓRIO INDEPENDENTE

2 ARQUIVO

3 INSTALADOR

Data Amostra nº

Soldadura nº Aterro de ...

Data Amostra nº


Data Amostra nº


1, 5 m

Sample: CQA; installer, file


Seam testing | non-destructive testsTest

methodDescription Applicability Comments

Air

lan

ce

A jet of compressed air is directed through a nozzle beneath the upper edge of the overlapped

seams. If a portion of seam leaks, either air flows under the geomembrane and inflates it, or

causes the geomembrane vibration. An audible sound change when unbounded areas are

encountered.

Mostly for flexible

geomembranes; best for thin

geomembranes (lower than

1mm).

Results not very

reproducible; very high

operator dependency.

Pre

ssu

rise

d

du

al s

ea

m

The gap existent in the double seams is pressurised by air injection during a certain period. If

no drop on the pressure gauge occurs during that time interval the seam is acceptable.

All type of geomembranes

seamed with double hot wedge

or double hot air.

Fast method. Sensitive to

the seam parameters.

Va

cuu

m

bo

x A soap solution is sprayed on the top of the seam. A transparent box is placed on the seam

and a vacuum is pulled in the box. If no bubbles or froth appear the seam is acceptable.

Mostly for stiff geomembranes;

mainly, for HDPE, of which the

thickness exceeds 1 mm.

Slow method; often

difficult to make a vacuum-

tight joint; mainly for

patches.

Ele

ctri

c

wir

e

A copper or stainless wire is placed between the overlapped sheets and embedded into the

completed seam. A charged probe of high-voltage (~20000 V) is connected to one end of the

wire and slowly moved over the entire seam. An audible alarm rings when defect is

encountered.

All types of geomembranes

seamed.High operator dependency.

Ele

ctri

cal

spa

rkin

g

A conduction wire inserted into the seam during seaming. By applying a suitable voltage above

the seams leakage to ground will transmit a spark, accompanied by an audible alarm signal.

All geomembranes, for areas

where vacuum cannot be used

such as corners.

Difficult to set up

accurately over large areas;

results not always reliable.

Ult

raso

nic

pu

lse

ech

o

Compares the measured thickness of the seam with the thickness that it should have. A high-

frequency pulse (5-15 MHz) is sent into the upper geomembrane, which will not be reflected

on the bottom of the lower one if an unbounded area is present.

Only for nonreinforced

geomembranes; not applicable

to extrusion fillet seams.

Qualitative result.

Ult

raso

nic

imp

ed

an

ce

pla

ne

A continuous wave (160-185 kHz) is transmitted through the seam by means of a transducer in

contact with the geomembrane and a characteristic dot pattern is displayed on a monitor. The

location of the dot pattern indicates if the seam is bonded or not. Calibration of the dot

pattern is required to signify a good seam.

Has potential for all types of

geomembranes.Qualitative result.

Ult

raso

nic

sha

do

w

It uses two roller transducers, one sends a multi-frequency pulse into the upper

geomembrane and the other receives the signal from the lower geomembrane on the other

side of the seam. The analyses of the displayed results (amplitude versus time) indicate the

quality of the seam.

Not applicable to reinforced

geomembranes; can be used for

all types of seams.

Best suited to

semicrystalline

geomembranes.

M.

pro

be

test Uses a stiff probe under the top edge of a seam to detect unbounded areas, which are easier

to split than the properly welded areas.

All geomembranes and all seams

with well-defined edge.

Depends largely on

sensitivity of the operator.

Vacuum box

Soap bubbles

pump


Seam testing | non-destructive tests | testing frequency

Testing frequency: 100% of the seams!

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Seam testing | corrective actions

> Patch (whenever possible made by thermal fusion)

> Removal and replacement of the seam (strip of GM

seamed on both sides by thermal fusion)

> Reinforce the seam (extrusion)

Non-destructive testing on all repairs!



� Anchor trench

� Panel placement

� Seams

� Seam testing



Protection of geomembrane

Geotextile

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Heavy equipment16%

Seams6%

Cuts1%

Works6%

Stones71%

Main cause of leaks in geomembrane liners (after covering layer installation)

Nosko & Touze-Foltz (2000)

CQC/CQA activities

Leak detection_ +

Leak

Geomembrane

D C

Cathode

Anode

Current

Electrical leak location methods locate leaks in the

geomembrane liner by applying an electrical potential

across the geomembrane and then locate areas where

electrical current flows through discontinuities in the liner

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CQC/CQA activities

Leak detection

solo fino

areiaGTX

GMBGCL

eléctrodo de injecção

Project PTDC/AAC-AMB/102846/2008

Small scale tests

CQC/CQA activities

Leak detectionProject PTDC/AAC-AMB/102846/2008

Prototype

CQC/CQA activities


Data acquisition system

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CQC/CQA activities


Data acquisition system

CQC/CQA activities

Similar activities for other

geosynthetics!.

Few examples on following

CQC/CQA activities

GCL: Overlaps

Longitudinal overlap

cross overlap

≥ 0.5 m

≥ 0.3 m

Spreader bar

“T” overlap

GCL

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CQC/CQA activities

GCL: Attachment details

bentonite

geotextile

cover soil

clamp

geotextile

GCL

CQC/CQA activities

GCL: Repairs

bentonite

patch

Summary

• Presentation and discussion of the main QC/CA

activities, highlighting the activities undertaken

during the installation of the geosynthetics

• Presentation focused on the geomembrane,

however, similar activities shall be performed with

the other geosynthetics, in order to assure that

materials and workmanship meet design

specifications

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References

• Barroso, Madalena & Lopes, M.G. (2008). Plano de Garantia de Qualidade da Instalação dos Geossintéticos (Plano GQIG) em Aterros de Resíduos. Informação Técnica do LNEC, ITG 27, Lisboa

• Barroso, Madalena & Lopes, M.G. (2007). “Ensinamentos recentes sobre o desempenho dos geossintéticos em sistemas de confinamento”. Seminário Geotécnico sobre Aterros de Resíduos, LNEC, Lisboa, Portugal, 29 p.

• Barroso, Madalena C.P. & Pardo de Santayana, F. (2004). “Contribuições geotécnicas para melhorar a construção dos sistemas de confinamento de aterros de RSU”. II congresso Luso-Brasileiro de Geotecnia, Aveiro, Portugal, pp. 229 – 238;

• Bouazza, A. Zornberg, J.G. & Adam, D. (2002). “Geosynthetics in waste containment facilities: Recent advances”. Keynote Paper, Proceedings of Seventh International Conference on Geosynthetics, Vol. 2, Nice, France, pp. 445-511.

• CEN TR 15019 (2005) - Geotextile and geotextile-related products: On-site quality control.

• Comité Français des Géosynthétiques (2003). “Présentation de méthods de détection et de localisation de défauts dans les dispositifs d’etanchéité par géomembranes”. 44 p.

• Daniel, D.E. & Koerner, R.M. (1993). “Quality assurance and quality control for waste containment facilities”. United States Environmental Protection Agency Report EPA/600/R-93/182, Cincinnati, OH, USA, 305 p.

• Directive DVS 2225 - Parte 4 (1996). “Soudage de géomembranes en polyethylene utilisées pour l’étanchéification de décharges d’ordure et des déchetes”. Institute de Soudure.

• EN ISO 10320 - “Geotextiles and geotextile-related products - identification on site”.

• GRI GM19 (2002). “Standard specification for seam strength and related properties of thermally bonded polyolefin geomembranes”. Geosynthetic Research Institute, Drexel University, USA. (Revista em 2003).

• Holtz, R.D.; Christopher, B.R. & Berg, R.R. (1997). Geosynthetic engineering. Published by BiTech Publishers Ltd., 452p.

• IAGI (Associação Internacional de Aplicadores de Geossintéticos) (2004). “Improving geomembrane installations”. White paper, 17 p.

• Koerner, R.M. & Lord Jr. A. E. (1990). “Nondestructive evaluation of geomembrane seams: methods in development”. Geotextiles and GeomembranesNo. 9 (4), pp 431-443.

• Koerner, R.M. (1998). Designing with Geosynthetics. Prentice Hall, Fourth Edition, 761 p.

• Lopes, M. G. (2006a). “Análise dos métodos de controlo de integridade de geomembranas de PEAD usadas em aterros de RSU”. Revista Geotecnia nº106, Março, pp. 107-131.

• Lopes, M. G. (2006b). “Experiência de colocação de geomembranas de PEAD em aterros de RSU”. Revista Geotecnia nº106, Março, pp. 55-74.

• Lopes, M.G. et al. (2002). Concepção, construção e exploração de tecnossistemas. Projectos, metodologias e tecnologias aplicadas em Portugal no período de 1996 a 2001. Edição do Instituto de Resíduos.

• Nosko, V. & Touze-Foltz, N. (2000). “Geomembrane liner failure: Modelling of its influence on contaminant transfer”. Proceedings of EuroGeo 2, Vol. 2, Bologna, Italy, pp. 557-560.

ACKNOWLEDGEMENTS

The author gratefully acknowledge Fundação para a

Ciência e Tecnologia (FCT), for financial support under

its Project PTDC/AAC-AMB/102846/2008

CQC-CQA procedures for different materials (EuroGeo5) · • number of samples: according the...

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