1

Mathews, Barbara

From: Arjmandi, MasoudSent: Friday, September 10, 2010 1:30 PMTo: Mathews, BarbaraSubject: FW: Upper Southwest Attachments: ADEQ Request2 for Sand Variance-lp-09.09.10.pdf

��-----Original Message----- From: Lance Powell [mailto:lpowell@ce-associates.biz] Sent: Thursday, September 09, 2010 3:46 PM To: Arjmandi, Masoud Cc: Leamons, Bryan; rebecca.hosey@live.com; 'Jeff Barfield' Subject: Upper Southwest ���Masoud,���On�behalf�of�the�Upper�Southwest�Arkansas�Regional�Solid�Waste�Management�District,�Civil�Engineering�Associates,�LLC�is�submitting�the�attached�information�associated�with�their�Class�1�landfill.���Thanks,���Lance�Powell,�P.E.�CIVIL�ENGINEERING�ASSOCIATES�2114�East�Matthews�Ave.�Jonesboro,�Arkansas�72401���Phone:�(870)�972�5316�Fax:�(870)�932�0432�Mobile:�(870)�243�9400�������

Rec’d Digitally

AFIN:_________________________

PMT#:_________________________ SW

DOC ID#:______________________ MD

TO:___________________________

By Barbara Mathews at 8:52 am, Sep 13, 2010

31-001070265-S1-R1

58239

MA> file

2114 East Matthews Avenue Jonesboro, Arkansas 72401 870-972-5316 Fax 870-932-0432

HOT SPRINGS � JONESBORO � POPLAR BLUFF

September 9, 2010 Arkansas Department of Environmental Quality Solid Waste Management Division Attn: Mr. Masoud Arjmandi 5301 Northshore Drive North Little Rock, Arkansas 72218 SUBJECT: Request for Alternate Leachate Drainage Layer Material Upper Southwest Arkansas Regional Solid Waste Management District

Solid Waste Permit No. 0265-S1-R1; AFIN 31-00107 ADEQ Document Reference Identifiers: 58175 and 58196 Dear Mr. Arjmandi, In accordance with Arkansas Department of Environmental Quality (ADEQ) Regulation 22.429 (b) (2), Civil Engineering Associates, LLC (CEA) submitted a request to the ADEQ for a variance from the grain size distribution testing requirement of ADEQ Regulation 22.429 (b) (1), for the referenced facility. As you are aware, the request was denied by the ADEQ in a letter dated September 1, 2010. On behalf of the Upper Southwest Arkansas Regional Solid Waste Management District (USARSWMD), CEA is asking the ADEQ to reconsider the request dated August 26, 2010 based on the enclosed information. ADEQ Regulation 22.429 (c) states that calculations or demonstrations must be provided to show that the leachate collection system will adequately dewater the waste mass and that clogging of the system will not occur. The primary reason for the grain size distribution requirement of Regulation 22.429 (b) (1) is to avoid the potential for clogging of the underlying leachate collection system. The enclosed Geotextile Filter Fabric Design and Clogging Potential Calculations demonstrate that a geotextile material for use around the leachate collection pipe can be selected to use with the material being proposed for the leachate drainage layer at the USARSWMD Class 1 Landfill. The grain size distribution of a sample of the actual sand proposed to be used was entered into the design software for selection of the appropriate geotextile material. The sand sample used for the calculations had 8.0 percent by weight passing the No. 200 sieve. Other grain size distribution testing that has been performed on the proposed sand by the USARSWMD has indicated typically 5 to 10 percent by weight finer than the No. 200 Sieve. The results of these tests are included with the calculations. As previously stated, the USARSWMD is requesting that the ADEQ reconsider the request that a maximum of 15 percent by weight passing the No. 200 sieve be allowed as a standard for material being utilized as the leachate drainage layer for the Class 1 landfill. Testing has already demonstrated that the material will meet the ADEQ Regulation 22.429 (b) permeability requirement of 1 x 10-3 cm/sec. In regard to the concern indicated in the September 1, 2010 letter that lab results and field performance could be quite different, the USARSWMD is proposing construction testing of the sand material at a rate of one test for every 5,000 cubic yards of material placed, which is not a specific requirement of ADEQ Regulation 22.

Upper Southwest Arkansas Regional Solid Waste Management District Class 1 Landfill Page 2

HOT SPRINGS � JONESBORO � POPLAR BLUFF

CEA appreciates the ADEQ’s consideration of this request. If you have any questions or need additional information, please contact me at (870) 972-5316. Sincerely, CIVIL ENGINEERING ASSOCIATES, LLC

Lance Powell, P.E. Project Manager Enclosure cc: Max Tackett (USARSWMD) Jeff Barfield (USARSWMD)

CALCULATION SUMMARY SHEET

PROJECT Upper Southwest Arkansas Regional Solid Waste Management DistrictClass 1 Landfill

PROJECT NO.SW-10-02

CALCULATION TITLE Geotextile Filter Fabric Design and Clogging Potential Calculations

CALCULATION NO. 1

ORIGINATED BY Lance Powell, P.E.

DATE 09/08/10

CHECKED BY Lance Powell, P.E.

DATE 09/08/10

SUBJECT:

The following calculations evaluate the potential for geotextile clogging as the basis for the design of the leachate collection system. This information provides the basis for construction technical specifications for the geotextile and leachate drainage layer materials to be used for future cell construction at the Upper Southwest Arkansas Regional Solid Waste Management District (USARSWMD) Class 1 Landfill.

DESCRIPTION OF PROBLEM:

The purpose of the geotextile filter fabric is to protect the leachate collection piping system while minimizing intrusion (clogging) from adjacent soil layers. This filter layer must be able to perform three functions. (i) The filter must prevent passage of significant amounts of soil; (ii) The filter must have a relatively high hydraulic conductivity; (iii) The soil particles in contact with the filter must not migrate significantly into the adjacent drainage layer.

Methods used to design the geotextile fabrics to be used at the USARSWMD Class 1 Landfill in conjunction with the proposed leachate drainage layer material, are based on methods developed by the Nicolon Corporation and Mirafi. These methods are widely used and accepted in the industry. The Mirafi Geotextile Filter Design, Application, and Product Selection Guide is enclosed for reference. The design guide was used in conjunction with Mirafi’s Geofilter 32 design software to prepare the enclosed calculations.

SUMMARY:

Specifications for the leachate collection system components involving geotextiles shall consider the following minimum standards based on the enclosed calculations:

1. The geotextile shall have a minimum permeability of 8.4 x 10-3 cm/s; 2. The geotextile shall have an Apparent Opening Size that is less than 0.21 mm. 3. The geotextile percent open area shall be 4 - 6% for woven geotextiles and the

porosity shall be at least 30%. 4. Geotextile fabric shall be a Mirafi 160N or equivalent.

In addition to the above conditions, the geotextile shall adhere to the following minimum specifications: Grab Strength (lbs): 160 Sewn Seam Strength (lbs) 145 Elongation (%): 50 Puncture Strength (lbs): 60 Burst Strength (psi): 190 Trapezoidal Tear (lbs): 60

SOURCES OF DATA:

Hari D. Sharma and Sangeeta P. Lewis. Waste Containment Systems. Waste Stabilization, and Landfills,John Wiley & Sons, Inc, 1994.

Donald H. Gray, Robert M. Koerner, and Xuede Qian. Geotechnical Aspects of Landfill Design and Construction, Prentice Hall, 2002.

Mirafi Geotextile Filter Design, Application, and Product Selection Guide (See Enclosed)

Geofilter 32 Design Software

INTENDED USE: � PRELIMINARY CALC.

� FINAL CALC.

� SUPERCEDES CALC NO.____________

� OTHER___________________________

REVNO

DESCRIPTION BY DATE CHK DATE

Geotextile filtration involves the movement of liquid through a geotextile fabric layer. At the same time, the fabric serves the purpose of retaining the soil on its upstream side. As such, both adequate permeability and soil retention are required simultaneously. As noted by Mirafi, filtration is summarized by the following two conflicting requirements:

� The filter must retain soil, implying that the size of filter pore spaces or openings should be smaller than a specified maximum value; and

� The filter must be permeable enough to allow a relatively free flow through it, implying that the size of filter porte spaces and the number of openings should be larger than a specified minimum value.

In designing geotextile filter fabrics to be used at the USARSWMD Class 1 Landfill, the following considerations were evaluated in accordance with the methodology recommended by Mirafi:

� Retention; � Permeability; � Anti-clogging; � Survivability; and � Durability.

STEP 1: APPLICATION FILTER REQUIREMENTS

Geotextile fabric materials to be used at the USARSWMD Class 1 Landfill will generally be associated with the leachate collection and removal systems for the individual waste disposal cells. The geotextiles will be used to wrap the leachate collection pipe and gravel bedding material.

Based on the above intended use, the drainage media adjacent to the geotextile will consist of washed gravel bedding leachate collection pipes. As noted in the Mirafi design guide, permeability and anti-clogging are favored in applications where the geotextile filter fabric will wrap collection pipe and gravel bedding.

STEP 2: BOUNDARY CONDITIONS

The applications described in Step 1 will generally involve situations where large confining stress conditions are inherently present. In other words, in most applications, the geotextile filter fabric will be situated under many layers of municipal solid waste and earthen material. The high confining stress could result in the following and must be considered in the design and selection of the filter media:

� High confining pressures tend to increase the relative density of coarse grained soil, increasing the soil’s resistance to particle movement. This affects the selection of retention criteria.

� High confining pressures decrease the hydraulic conductivity of fine grained soils, increasing the potential for soil to intrude into, or through the geotextile filter.

� High confining pressures increase the potential for the geotextile and soil mass to intrude into flow paths reducing flow capacity within the drainage media, especially when geosynthetic drainage cores are used.

Flow conLandfillcalculati

STEP 3

The parretentionchart besize.

nditions forare best reions.

3: SOIL R

rticle size on criteria foelow for ste

r the designepresented

RETENTI

of the adjaor the filteready state f

n of the geoby steady

ON REQU

acent soil mr fabric desflow conditi

otextile comy state flow

UIREMEN

materials prsign. As sons is used

mponents atw conditions

NTS

rovide the hown in thd to determ

t the USARs for the pu

basis for dhe Mirafi demine the ap

RSWMD Claurpose of t

determiningesign guidepparent ope

ass 1 hese

g the e the ening

The soils in contact with the geotextile fabric at the USARSWMD Class 1 Landfill will generally consist of soils with 5 to 10% fines passing the No. 200 Sieve. The particle size distribution of the sand proposed to be in contact with the geotextile, based on laboratory analysis, was entered into the Geofilter design software to determine the maximum allowable geotextile opening size. It was determined that an apparent opening size of O95 not more than 0.21 mm is required for the given applications at the USARSWMD Class 1 Landfill. The results from the grain size distribution testing of the sand, as well as additional sieve analysis with the No. 200 Sieve specifically, are attached with these calculations.

STEP 4: GEOTEXTILE PERMEABILITY REQUIREMENTS

The minimum allowable permeability of the geotextile is based on the requirement that the permeability of the geotextile must be greater than the permeability of the overlying soil. A permeability of 1X10-3 cm/sec is assumed for the overlying soil. However, this value should be confirmed during the construction of the leachate drainage layer.

The geotextile permeability is affected by the filter application, flow conditions, and soil type. Based on Giroud, 1988, the following formula can be used to determine the minimum geotextile permeability:

Kg > is ks

From Table 1 (See Mirafi Design Guide), a gradient of 1.5 is recommended for leachate collection and removal system designs. Therefore…

Kg > (1.5) x (1.0 x 10-3 cm/s) Kg > 1.5 x 10-3 cm/s

It is important to recognize that many of the geotextile laboratory test properties represent ideal conditions and thereby result in artificially high numeric values when used in design. As such, a laboratory test value can not generally be used directly and must be modified for in-situ conditions. To compensate for the difference between laboratory measured values and true performance values the following reduction factors have been utilized (Gray,2002):

Soil Clogging and Blinding Reduction Factor 5.0 Creep Reduction of Void Space Reduction Factor 1.5 Reduction Factor for adjacent material intruding

into geosynthetic void spaces 1.0 Chemical Clogging Reduction Factor 1.5 Biological Clogging Reduction Factor 5.0

As such, the allowable minimum property for hydraulic conductivity of the geotextile is 8.4 x 10-3 cm/s (1.5 x 10-3 cm/s x 5.0 x 1.5 x 1.0 x 1.5 x 5).

When evaluating suitability of various geotextiles, the permeability can be derived by multiplying the permittivity of the geotextile times the thickness.

STEP 5: ANTI-CLOGGING REQUIREMENTS

Clogging can be minimized by adhering to the following criteria:

� Use the largest opening size (O95) that satisfies the retention criteria. � For nonwoven geotextiles, use the largest porosity available, never less than

30%.� For woven geotextiles, use the largest percentage of open area available, never

less than 4%.

STEP 6: SURVIVABILITY REQUIREMENTS

Geotextiles can be damaged during construction depending on how they are placed and the materials adjacent to the geotextile fabric. Construction survivability can be assured by specifying the minimum strength properties that fit with the severity of the installation. Table 2 in the Mirafi Design Guide provides recommendations for various applications.

Assuming a subsurface application with high contact stresses, the following strength requirements are recommended (AASHTO, 1996):

Grab Strength (lbs): 160 Elongation (%) 50 Sewn Seam Strength (lbs): 145 Puncture Strength (lbs): 60 Burst Strength (lbs): 190 Trapezoidal Tear (lbs): 60

To allow for the required flow through the geotextile, void spaces must be sufficiently large. However, soil and waste particles should not pass through the fabric with the flowing liquid. This leads to a situation where finer soil particle increase until the upper gradient soil collapses. The result will be a minute sinkhole type pattern that grows larger with time. This undesired process can be prevented by making geotextile voids small enough to retain the soil.

STEP 7: DURABILITY REQUIREMENTS

Geotextiles are susceptible to UV deterioration if exposed to sunlight for extended periods. The geotextile applications planned for the USARSWMD Class 1 Landfill generally will not require extended periods of UV exposure. Geotextiles made from polyprobylene are generally inert to most naturally occurring chemicals. A Mirafi 160N or equivalent non-woven geotextile fabric is recommended for the conditions described herein. A product data sheet for the Mirafi 160N is attached for reference.

ATTACHMENTS

Marine & Transportation Engineering

geotextile filter design,application, and productselection guide

Introduction and Explanation of the Problem ....................................... 1

The Mirafi® Solution ...................................................................... 1

Systematic Design Approach .......................................................... 2

Step One:Application Filter Requirements ................................................ 3

Step Two:Boundary Conditions ............................................................. 3

Step Three:Soil Retention Requirements .................................................... 4

Step Four:Geotextile Permeability Requirements ........................................ 5

Step Five:Anti-Clogging Requirements .................................................... 6

Step Six:Survivability Requirements ..................................................... 7

Step Seven:Durability Requirements ......................................................... 7

Geotextile Filter Selection Guide ...................................................... 8

Geotextile Filter Minimum AveragePhysical Properties Chart ........................................................ 10

TABLE OFCONTENTS

GEOTEXTILE FILTER DESIGN, APPLICATION, AND PRODUCTSELECTION GUIDE

Drainage and Erosion Control Applications

Drainage

Geotextile filters retain soil particleswhile allowing seeping water to drainfreely. Fine soil particles are preventedfrom clogging drainage systems.

1

Filtration geotextiles provide alternatives to graded filters.

SOLUTION

DrainageAggregate trench and blanket drains are commonly used to drain water from

surrounding soils or waste materials. These drains are typically installed less thanthree feet deep. They may be at greater depths in situations where there is a needto significantly lower the groundwater table or to drain leachate.

In loose or gap graded soils, the groundwater flow can carry soil particlestoward the drain. These migrating particles can clog drainage systems.

Erosion ControlStone and concrete revetments are often used on waterway slopes to resist soil

erosion. These armored systems, when placed directly on the soil, have not suffi-ciently prevented erosion. Fluctuating water levels cause seepage in and out ofembankment slopes resulting in the displacement of fine soil particles.

As with trench drains, these fine soil particles are carried away with recedingflows. This action eventually leads to undermining of the armor system.

Typical SolutionsSpecially graded fill material which is intended to act as a soil filter is frequently

placed between the drain or revetment and the soil to be protected. This graded fil-ter is often difficult to obtain, expensive to purchase, time consuming to install andsegregates during placement, thus compromising its filtration ability.

AND EXPLANATION OFTHE PROBLEM

Erosion Control

Geotextile filters retain soil particleswhile allowing water to pass freely.Buildup of hydrostatic pressures in pro-tected slopes is prevented, thusenhancing slope stability.

INTRODUCTION

THE MIRAFI®

Designing with Geotextile FiltersGeotextiles are frequently used in armored erosion control and drainage applica-

tions. Some of the most common applications include slopes, dam embank-ments/spilllways, shorelines armored with riprap, flexible block mats and concretefilled fabric formed systems. Drainage applications include pavement edge drains,french drains, prefabricated drainage panels and leachate collection/leak detectionsystems.

In all of the above applications, geotextiles are used to retain soil particles whileallowing liquid to pass freely. But the fact that geotextiles are widely used wheretheir primary function is filtration, there remains much confusion about proper filtra-tion design procedures.

For this reason, Mirafi® commissioned Geosyntec Consultants, Inc. to develop a generic Geotextile Filter Design Manual. The manual offers a systematicapproach to solving most common filtration design problems. It is available to prac-ticing designers exclusively through Mirafi®. This Geotextile Filter Design, Applica-tion, and Product Selection Guide is excerpted from the manual.

2

• The filter must retain soil, implyingthat the size of filter pore spaces oropenings should be smaller than aspecified maximum value; and

Mechanisms of FiltrationA filter should prevent excessive migration of soil particles, while at the same

time allowing liquid to flow freely through the filter layer. Filtration is thereforesummarized by two seemingly conflicting requirements.

• Retention: Ensures that the geo-textile openings are small enough toprevent excessive migration of soilparticles.

• Permeability: Ensures that the geo-textile is permeable enough to allowliquids to pass through without caus-ing significant upstream pressurebuildup.

• Anti-clogging: Ensures that thegeotextile has adequate openings,preventing trapped soil from clog-ging openings and affecting perme-ability.

Geotextile Filter RequirementsBefore the introduction of geotextiles, granular materials were widely used

as filters for geotechnical engineering applications. Drainage criteria for geotextile fil-ters is largely derived from those for granular filters. The criteria for both are, therefore,similar.

In addition to retention and permeability criteria, several other considerations arerequired for geotextile filter design. Some considerations are noted below:

• The filter must be permeableenough to allow a relatively free flowthrough it, implying that the size offilter pore spaces and number ofopenings should be larger than aspecified minimum value.

• Survivability: Ensures that thegeotextile is strong enough toresist damage during installa-tion.

• Durability: Ensures that the geotextile is resilient to adversechemical, biological and ultravi-olet (UV) light exposure for thedesign life of the project.

The specified numerical criteria for geotextile filter requirements depends on theapplication of the filter, filter boundary conditions, properties of the soil being filtered,and construction methods used to install the filter. These factors are discussed inthe following step-by-step geotextile design methodology

DESIGN APPROACH

SYSTEMATICThe proposed design methodology represents years of research and experi-

ence in geotextile filtration design. The approach presents a logical progressionthrough seven steps.

Step 1: Define the Application Filter Requirements

Step 2: Define Boundary Conditions

Step 3: Determine Soil Retention Requirements

Step 4: Determine Permeability Requirements

Step 5: Determine Anti-Clogging Requirements

Step 6: Determine Survivability Requirements

Step 7: Determine Durability Requirements

Design Methodology

DEFINEBOUNDARY CONDI-TIONS

STEP TWO:

3

• Sharp contact points such as highlyangular gravel or rock will influencethe geosynthetic survivability require-ments.

• For all soil conditions, high confining pressures increase thepotential for the geotextile and soilmass to intrude into the flow paths.This can reduce flow capacity withinthe drainage media, especially whengeosynthetic drainage cores areused.

Geotextile filters are used between the soil and drainage or armoring medium.Typical drainage media include natural materials such as gravel and sand, as wellas geosynthetic materials such as geonets and cuspated drainage cores. Armoringmaterial is often riprap or concrete blocks. Often, an armoring system includes asand bedding layer beneath the surface armor. The armoring system can be con-sidered to act as a “drain” for water seeping from the protected slope.

Identifying the Drainage MaterialThe drainage medium adjacent to the geotextile must be identified. The primary

reasons for this include:

Retention vs. Permeability Trade-OffThe drainage medium adjacent to the geotextile often affects the selection

of the retention criterion. Due to the conflicting nature of filter requirements, it is necessary to decide whether retention or permeability is the favored filter charac-teristic.

For example, a drainage material that has relatively little void volume (i.e., a geonet or a wick drain) requires a high degree of retention from the filter.Conversely, where the drainage material void volume is large (i.e., a gravel trench orriprap layer), the permeability and anti-clogging criteria are favored.

Define Flow ConditionsFlow conditions can be either steady-state or dynamic. Defining these conditions

is important because the retention criteria for each is different. Examples of appli-cations with steady-state flow conditions include standard dewatering drains, walldrains and leachate collection drains. Inland waterways and shoreline protectionare typical examples of applications where waves or water currents cause dynamicflow conditions.

Evaluate Confining StressThe confining pressure is important for several reasons:

• Large voids or high pore volume caninfluence the selection of the reten-tion criterion

• High confining pressures tend toincrease the relative density ofcoarse grained soil, increasing thesoil’s resistance to particle move-ment. This affects the selection ofretention criteria.

• High confining pressures decreasethe hydraulic conductivity of finegrained soils, increasing the potential for soil to intrude into, or through, the geotextile filter.

DEFINEAPPLICATION FILTER REQUIRE-MENTS

STEP ONE:

Chart 1. Soil Retention Criteria of Steady-State Flow Conditions

4

DETERMINESOIL RETENTIONREQUIREMENTS

STEP THREE:

USETANGENT AT

d50 C’u

UNSTABLESOIL

MORE THAN20% CLAY

NON-DISPERSIVE SOIL

DISPERSIVE SOIL(DHR > 0.5)

(DHR < 0.5)

O95 < 0.21MM

USE 3 TO 6 INCHES OF VERY FINE SAND BETWEENSOIL AND GEOTEXTILE, THEN DESIGN THE GEOTEX-

TILE AS A FILTER FOR THE SAND

STABLESOIL USE

USE

d60

d30C’u

d30

d10C’u

(1 ≤ Cc ≤ 3)

(Cc > 3 orCc < 1)

WIDELYGRADED

MEDIUM(35% < ID < 65%) O95 <

13.5

C’ud’50

DENSE(ID > 65%)

O95 <18C’u

d’50

LOOSE(ID < 35%)

O95 < 9C’u

d’50

UNIFORMLYGRADED

MEDIUM(35% < ID < 65%)

DENSE(ID > 65%)

LOOSE(ID < 35%) O95 < C’u d’50

O95 < 1.5 C’u d’50

O95 < 2 C’u d’50

C’u > 3

C’u < 3

APPLICATIONFAVORS

RETENTION

APPLICATIONFAVORS

PERMEABILITY

PLASTIC SOIL

Pl > 5

NON-PLASTIC SOIL

Pl < 5

MORE THAN90% GRAVEL

d10 > 4.8mm

d20 < 0.002mm

LESS THAN10% SILT, andMORE THAN10% SAND

LESS THAN 20% CLAY, andMORE THAN 10% SILT

(d10 > 0.07mmand

d10 < 4.8mm)

(d20 > 0.002mm andd10 < 0.07mm)

FROM SOILPROPERTIES TESTS

NOTES:

relative density of the soilplasticity index of the soildouble-hydrometer ratio of the soilgeotextile opening size

IDPl

DHRO95

====

Cc =

=

=

(d30)2

d60 X d10dx

C’ud’100

d’0

particle diameter of which size x percent is smaller

where: d’100 and d’0 are the extremeties of a straight line drawnthrough the particle-size distribution, as directed above andd’50 is the midpoint of this line

Charts 1 and 2 indicate the use of particle-sizeparameters for determing retention criteria. Thesecharts show that the amount of gravel, sand, silt andclay affects the retention criteria selection process.Chart 1 shows the numerical retention criteria forsteady-state flow conditions; Chart 2 is for dynamicflow conditions.

For predominantly coarse grained soils, the grain-size distribution curve is used to calculate specificparameters such as Cu, C'u, Cc, that govern the retention criteria.

Chart 2. Soil Retention Criteria of Dynamic Flow Conditions

• For non-critical applications, estimate the soil-hydraulic conduc-tivity using the characteristic graindiameter d15, of the soil (see Figure2 on the following page).

• For critical applications, such asearth dams, soil permeability shouldbe lab measured using representative field conditions inaccordance with test procedureASTM D 5084.

Analysis of the soil to be protected is critical to proper filtrationdesign.

Define Soil Particle-Size DistributionThe particle-size distribution of the soil to be protected should be determined

using test method ASTM D 422. The grain size distribution curve is used to deter-mine parameters necessary for the selection of numerical retention criteria.

Define Soil Atterberg LimitsFor fine-grained soils, the plasticity index (PI) should be determined using

the Atterberg Limits test procedure (ASTM D 4318). Charts 1 and 2 show how to use the PI value for selecting appropriate numerical retention criteria.

Determine the Maximum Allowable Geotextile Opening Size (O95)The last step in determining soil retention requirements is evaluating the maxi-

mum allowable opening size (O95) of the geotextile which will provide adequate soil retention. The O95 is also known as the geotextile’s Apparent Open-ing Size (AOS) and is determined from test procedure ASTM D 4751. AOS canoften be obtained from manufacturer’s literature.

Define the Soil Hydraulic Conductivity (ks)Determine the soil hydraulic conductivity, often referred to as permeability, using

one of the following methods:

5

DETERMINEGEOTEXTILE PERME-ABILITY REQUIRE-MENTS

STEP FOUR:

MORE THAN20% CLAY

NON-DISPERSIVE SOIL

DISPERSIVE SOIL(DHR > 0.5)

(DHR < 0.5)

O95 < 0.21MM

USE 3 TO 6 INCHES OF VERY FINE SAND BETWEENSOIL AND GEOTEXTILE, THEN DESIGN THE GEOTEX-

TILE AS A FILTER FOR THE SAND

SEVERE WAVE ATTACK

MILD WATER CURRENTS

PLASTIC SOIL

Pl > 5

NON-PLASTIC SOIL

Pl < 5

MORE THAN90% GRAVEL

d10 > 4.8mm

d20 < 0.002mm

LESS THAN10% SILT, andMORE THAN10% SAND

LESS THAN 20% CLAY, andMORE THAN 10% SILT

(d10 > 0.07mmand

d10 < 4.8mm)

(d20 > 0.002mm andd10 < 0.07mm)

FROM SOILPROPERTIES TESTS

particle diameter of which size x percent is smallerplasticity index of the soildouble-hydrometer ratio of the soilgeotextile opening sized60 / d10

dxPlDHRO95Cu

=====

O95 < d50

O95 < 2.5 d50 and O95 < d90

d50 < O95 < d90

Cu > 5

Cu < 5

NOTES:

6

DETERMINEGEOTEXTILE PERME-ABILITY REQUIRE-MENTS(continued)

STEP FOUR:

Define the Hydraulic Gradient for the Application (is)The hydraulic gradient will vary depending on the filtration application.

Anticipated hydraulic gradients for various applications may be estimated usingTable 1 below.

Drainage Applications Typical Hydraulic GradientChannel Lining 1.0Standard Dewatering Trench 1.0Vertical Wall Drain 1.5Pavement Edge Drain 1.0Landfill LCDRS 1.5Landfill LCRS 1.5Landfill SWCRS 1.5Shoreline Protection

Current Exposure 1.0(b)

Wave Exposure 10(b)

Dams 10(b)

Liquid Impoundments 10(b)

Table 1. Typical Hydraulic Gradients(a)

Figure 2. Typical Hydraulic Conductivity Values

(a) Table developed after Giroud, 1988.(b) Critical applications may require designing with higher gradients than those given.

Determine the Minimum Allowable Geotextile Permeability (kg)The requirement of geotextile permeability can be affected by the filter appli-

cation, flow conditions and soil type. The following equation can be used for allflow conditions to determine the minimum allowable geotextile permeability(Giroud, 1988):

kg ≥ is ks

Permeability of the geotextile can be calculated from the permittivity testprocedure (ASTM D 4491). This value is often available from manufacturer’s lit-erature. Geotextile permeability is defined as the product of the permittivity, Ψ,and the geotextile thickness, tg:

kg = Ψtg

Both the type of drainage or armor material placed adjacent to the geotextileand the construction techniques used in placing these materials can result in dam-age to the geotextile. To ensure construction survivability, specify the minimumstrength properties that fit with the severity of the installation. Use Table 2 as aguide in selecting required geotextile strength properties to ensure survivability forvarious degrees of installation conditions. Some engineering judgement must beused in defining this severity.

7

• For woven geotextiles, use thelargest percentage of open areaavailable, never less than 4%.

NOTE: For critical soils and applica-tions, laboratory testing is recommend-ed to determine geotextile cloggingresistance.

• Use the largest opening size (O95)that satisfies the retention criteria.

• For nonwoven geotextiles, use thelargest porosity available, never lessthan 30%.

To minimize the risk of clogging, follow this criteria:

DETERMINEANTI-CLOGGINGREQUIREMENTS

STEP FIVE:

During installation, if the geotextile filter is exposed to sunlight for extended peri-ods, a high carbon black content and UV stabilizers are recommended for addedresistance to UV degradation. Polypropylene is one of the most durable geotextilestoday. It is inert to most naturally occurring chemicals in civil engineering applica-tions.

However, if it is known that the geotextile may exposed to adverse chemicals(such as in waste containment landfill applications), use test method ASTM D5322to determine its compatibility.

DETERMINESURVIVABILITYREQUIREMENTS

STEP SIX:

DETERMINE DURABIL-ITY REQUIREMENTS

STEP SEVEN:

Table 2. Survivability Strength Requirements (after AASHTO, 1996)

ReferencesGiroud, J.P., “Review of Geotextile Filter Design Criteria.” Proceedings of First Indian Conference on Reinforced Soil

and Geotextiles, Calcutta, India, 1988.Heerten, G., “Dimensioning the Filtration Properties of Geotextiles Considering Long-Term Conditions.” Proceedings of

Second International Conference on Geotextiles, Las Vegas, Nevada, 1982.AASHTO, “Standard Specification for Geotextile Specification for Highway Applications”, M288-96

GRAB STRENGTH(LBS)

SEWN SEAMSTRENGTH (LBS)

PUNCTURESTRENTH (LBS)

BURSTSTRENTH (LBS)

TRAPEZOIDTEAR (LBS)

ELONGATION(%)

247 < 50% * 222 90 392 56

157 > 50% 142 56 189 56

HIGH CONTACT STRESSES

(ANGULAR DRAINAGE MEDIA)(HEAVY COMPACTION) or

(HEAVY CONFINING STRESSES)SUBSURFACE

DRAINAGE

LOW CONTACT STRESSES

(ROUNDED DRAINAGE MEDIA)(LIGHT COMPACTION) or

(LIGHT CONFINING STRESSES)

HIGH CONTACT STRESSES

(DIRECT STONE PLACEMENT)(DROP HEIGHT > 3 FT)

ARMOREDEROSION CONTROL

LOW CONTACT STRESSES

(SAND OR GEOTEXTILECUSHION) and

(DROP HEIGHT < 3 FT)

180 < 50% * 162 67 305 56

112 > 50% 101 40 138 40

247 < 50% * 222 90 392 56

202 > 50% 182 79 247 79

247 < 50% * 222 90 292 56

157 > 50% 142 56 189 56

Only woven monofilament geotextiles are acceptable as < 50% elongation filtra-tion geotextiles. No woven slit film geotextiles are permitted.

*

Mild

Cur

rent

Exp

osur

e,M

inim

al D

raw

dow

n Po

ten-

tial,

Non-

Vege

tate

d

FILTERWEAVE 400 FILTERWEAVE 400 FILTERWEAVE 400 MIRAFI 180N

GEOTEXTILE FILTER FABRIC SELECTION GUIDE

Silty Sand (SM)

ks = .00005cm/sPI = 0

Cc = 3.0C'u = 16.2d'50 = .21Cu = 67

d50 = .22mmd90 = .95mm

(Note: Moderate toHeavy Compaction

Required)

Well-GradedSilty Sand

(SW) #2

ks = .001cm/sPI = 0

Cc = 2.1C'u = 5.3

d'50 = .28mmCu = 6.6

d50 = .28mmd90 = 1.6mm

Well-GradedSand

(SW) #1

ks = .005cm/sPI = 0

Cc = 1.0C'u = 9.1

d'50 = .52mmCu = 8.4

d50 = .60mmd90 = 2.7mmS

OIL

PR

OP

ER

TIE

S

Silty Gravelw/Sand

(GM)

ks = .005cm/sPI = 0

Cc = 2.8C'u = 34

d'50 = 3.5mmCu = 211

d50 = 5.0mmd90 = 22mm

Soil Retention(1)

Permeability

Clogging Resistance

Survivability Req’t

Gradation

Relative Soil Density

1.85 mm

5 x 10-3

P.O.A. > 6%

LOW

Widely Graded

Dense

1.03 mm

5 x 10-3

P.O.A. > 6%

LOW

Widely Graded

Dense

.95 mm

1 x 10-3

P.O.A. > 6%

LOW

Widely Graded

Dense

.18 mm

5 x 10-5

n > 30%

LOW

Widely Graded

Medium

SUBS

URFA

CE D

RAIN

AGE(2

)W

ave

Expo

sure

, Hig

hVe

loci

ty C

hann

el L

inin

g,Sp

illw

ay O

vert

oppi

ng

FILTERWEAVE 404 FILTERWEAVE 404 FILTERWEAVE 404 MIRAFI 180N

Soil Retention(1)

Permeability

Clogging Resistance

Survivability Req’t

Gradation

Relative Soil Density

.93 mm

5 x 10-3

P.O.A. > 6%

HIGH

Widely Graded

Loose

.51 mm

5 x 10-3

P.O.A. > 6%

HIGH

Widely Graded

Loose

.48 mm

1 x 10-3

P.O.A. > 6%

HIGH

Widely Graded

Loose

.18 mm

5 x 10-5

n > 30%

HIGH

Widely Graded

Medium

FILTERWEAVE 400 FILTERWEAVE 400 FILTERWEAVE 400 FILTERWEAVE 400

Soil Retention(1)

Permeability

Clogging Resistance

Flow Conditions

12.5 mm

5 x 10-3

P.O.A. > 6%

Mild Currents

1.5 mm

5 x 10-3

P.O.A. > 6%

Mild Currents

0.7 mm

1 x 10-3

P.O.A. > 6%

Mild Currents

0.55 mm

5 x 10-5

P.O.A. > 6%

Mild Currents

RECOMMENDEDFABRIC

FILTERWEAVE 404 FILTERWEAVE 404 FILTERWEAVE 500 FILTERWEAVE 700

Soil Retention(1)

Permeability

Clogging Resistance

Flow Conditions

5.0 mm

.5 x 10-2

P.O.A. > 6%

Severe Wave Attack

0.60 mm

.5 x 10-2

P.O.A. > 6%

Severe Wave Attack

0.28 mm

1 x 10-2

P.O.A. > 6%

Severe Wave Attack

0.22 mm

5 x 10-4

P.O.A. > 6%

Severe Wave Attack

RECOMMENDEDFABRIC

1 Maximum opening size of geotextile (O95) to retain soil. 2 Steady state flow condition. 3 Dynamic Flow Conditions

RECOMMENDEDFABRIC

RECOMMENDEDFABRIC

ARM

ORED

ERO

SION

CON

TROL

(3)

Lean Clay(CL)

ks = .0000001cm/sPI = 16.7Cc = 3.3C'u = n/ad'50 = n/aCu = 36

d50 = .014mmd90 = .05mm

> 16% silt< 20% clay

Sandy Silt(ML)

ks = .00005cm/sPI = 0

Cc = 2.9C'u = 1.7d'50 = .07Cu = 10.8

d50 = .072mmd90 = .13mm

Clayey Sand(SC)

ks = .00001cm/sPI = 16.0Cc = 20

C'u = n/ad'50 = n/aCu = 345

d50 = .55mmd90 = 5.8mm> 10% silt< 20% clay

.21 mm

1 x 10-5

n > 30%

LOW

Non-dispersive

.24 mm

5 x 10-5

n > 30%

LOW

Uniformly Graded

Dense

.21 mm

1 x 10-7

n > 30%

LOW

Non-dispersive

AGGREGATE

PERFORATED PIPE

PAVEMENT

GEOTEXTILEFILTER FABRIC

GeotextileFilter Fabric

6” Minimum Granular fill

Compacted Native Soil

Geogrid

Compacted Drainage Fill

Surcharge

NONWOVEN GEOTEXTILE

GEOTEXTILEFILTER FABRIC

LINER

DRAINAGE LAYER

ROCK REVETMENT

GEOTEXTILE FILTER FABRIC

GEOTEXTILE F

• Structure PressureRelief

• Foundation Wall Drains• Retaining Wall Drains• Bridge Abutment

Drains• Planter Drains

• Leachate Collectionand Removal

• Blanket Drains• Subsurface Gas Col-

lection

Proper installation of filtration geotextiles includes anchor-ing the geotextile in key trenches at the top and bottom of

• River and Streambed Lin-ing

• Culvert Inlet and DischargeAprons

• Abutment Scour Protection• Access Ramps

Underwater geotextile placement is common and mustinclude anchorage of the toe to resist scour.

MIRAFI 140N Series MIRAFI 140N SeriesMIRAFI 140N Series

.21 mm

1 x 10-5

n > 30%

HIGH

Non-dispersive

.18 mm

5 x 10-5

n > 30%

HIGH

Uniformly Graded

Medium

.21 mm

1 x 10-7

n > 30%

HIGH

Non-dispersive

MIRAFI 180N MIRAFI 160NMIRAFI 160N

1.4 mm

1 x 10-5

P.O.A. > 6%

Mild Currents

0.13 mm

5 x 10-5

n > 30%

Mild Currents

0.035 mm

1 x 10-7

n > 30%

Mild Currents

MIRAFI 1100N MIRAFI 1160NFILTERWEAVE 400

0.55 mm

1 x 10-4

P.O.A. > 6%

Severe Wave Attack

0.07 mm

5 x 10-4

P.O.A. > 6%

Severe Wave Attack

0.014 mm

1 x 10-6

n > 30%

Severe Wave Attack

MIRAFI 1160N MIRAFI 1160NFILTERWEAVE 404

• Seepage Cut-off• Pavement Edge Drains• Slope Seepage Cut-off• Surface Water Recharge• Trench or "French"

Drains

TYPICAL SECTIONS AND APPLICATIONS:

• Coastal Slope Protection• Shoreline Slope Protection• Pier Scour Protection• Sand Dune Protection

DISCLAIMERThe information presented herein will not apply to every instal-lation. Applicability of products will vary as a result of site con-ditions and installation procedures. Final determination of thesuitability of any information or material for the use contem-plated, of its manner of use, and whether the use infringes anypatents, is the sole responsibility of the user.

Mirafi® is a registered trademark of Nicolon Corporation.

DRAINAGE

ARMORED EROSION CONTROL

For more information on Mirafi® Geotextiles Filters in drainge and armored erosion control applications, contact one of the following offices:

In North America contact: log on to our website:Ten Cate Nicolon www.tcnicolon.com365 South Holland DrivePendergrass, Ga. 30567706-693-2226Toll free: 888-795-0808Fax: 706-695-4400

In Europe contact:Ten Cate Nicolon EuropeSluiskade NZ 14Postbus 2367600 AE AlmeloThe NetherlandsTel: +31-546-544487Fax: +31-546-544490

In Asia contact:Royal Ten Cate Regional Office11th Floor, Menara GlomacKelana Business Centre97, Jalan SS 7/247301 Petaling JayaSelangor Darul Ehsan MalaysiaTel: +60-3-582-8283Fax: +60-3-582-8285

In Latin America & Caribbean contact:Ten Cate Nicolon5800 Monroe RoadCharlotteNorth Carolina 28212USATel: 704-531-5801Fax: 704-531-5801

FGS000361 ETQR49

Mirafi® 160N is a needlepunched nonwoven geotextile composed of polypropylene fibers, which are formed into a stable network such that the fibers retain their relative position. Mirafi® 160N geotextile is inert to biological degradation and resists naturally encountered chemicals, alkalis, and acids. Mirafi® 160N meets Aashto M288-06 Class 2.

Mechanical Properties Test Method Unit Minimum Average

Roll Value MD CD

Grab Tensile Strength ASTM D 4632 N (lbs) 712 (160) 712 (160) Grab Tensile Elongation ASTM D 4632 % 50 50 Trapezoid Tear Strength ASTM D 4533 N (lbs) 267 (60) 267 (60) CBR Puncture Strength ASTM D 6241 N (lbs) 1780 (400)

Apparent Opening Size (AOS)1 ASTM D 4751 mm (U.S. Sieve) 0.212 (70) Permittivity ASTM D 4491 sec-1 1.4 Flow Rate ASTM D 4491 l/min/m2 (gal/min/ft2) 4481 (110)

UV Resistance (at 500 hours) ASTM D 4355 % strength retained 70

1 ASTM D 4751: AOS is a Maximum Opening Diameter Value NTPEP No. GTX-08-04-20

Physical Properties Test Method Unit Typical Value Weight ASTM D 5261 g/m2 (oz/yd2) 220 (6.5)

Thickness ASTM D 5199 mm (mils) 1.7 (65) Roll Dimensions (width x length) -- m (ft) 4.5 x 91 (15 x 300)

Roll Area -- m2 (yd2) 418 (500) Estimated Roll Weight -- kg (lb) 97 (215)

Disclaimer: TenCate assumes no liability for the accuracy or completeness of this information or for the ultimate use by the purchaser. TenCate disclaims any and all express, implied, or statutory standards, warranties or guarantees, including without limitation any implied warranty as to merchantability or fitness for a particular purpose or arising from a course of dealing or usage of trade as to any equipment, materials, or information furnished herewith. This document should not be construed as engineering advice. © 2010 TenCate Geosynthetics North America Mirafi® is a registered trademark of Nicolon Corporation

Mirafi® 160N