Table 6. Data Requirements and Testing Standards for Soils and Dredged Material (cont.)

ERDC TN-DOER-R6

December 2004

Table 6 (Concluded)

ASTM Procedures

and References

Requirement

Comments

Procedures for establishing the optimum dry unit weight

Moisture Content and Dry

ASTM D4959-00

and water content ranges required for attainment of the

Unit Weight

(ASTM 2000b)

desired hydraulic conductivity are discussed in Daniel

Daniel and Benson

and Benson (1990). These procedures involve the

(1990)

compaction and permeameter evaluation of five or six

soil samples at each of the three compactive efforts:

modified Proctor, standard Proctor, and "reduced"

Proctor, for a total of 15 to 18 analyses for each soil to

be evaluated for use.

Hydraulic Conductivity and

Increased accuracy of conductivity estimates will be

Permeability

assured if test materials are in a compaction state

similar to the condition expected in the field.

Constant Head Perme-

ASTM 2434-68

For high hydraulic conductivity materials.

ameter

(ASTM 2000e)

Flexible Wall Perme-

ASTM 5084-00

For low and high hydraulic conductivity materials.

ameter

(ASTM 2000f)

Evaluation of

PSDDF

Provides a means to estimate hydraulic conductivity of

consolidation,

(Stark 1996)

liner materials following consolidation.

compression, and

desiccation of dredged

fill for determining

long-term storage

requirements

Synthetic Liners. Utilization of synthetic materials, including geomembranes, geonets, and geotextiles,

in CDF liners and leachate collection systems also requires testing of individual components for

compliance with contract specifications.

Serving as relatively impermeable barriers to liquids or vapors, geomembranes typically possess

permeability (measured by water vapor transmission tests (ASTM 1995) from 0.3x10-10 cm/sec to 0.5x10-13

cm/sec. Table 7 summarizes additional recommended minimum properties for geomembranes, including

applicable ASTM test methods for thickness, tensile strength, tear resistance, puncture resistance, and

impact resistance.

Leachate Collection Systems. Leachate collection systems are comprised of geosynthetic materials

(geotextiles overlying geonets), natural materials (sand or gravel filtration and drainage layers), or a

combination of geosynthetics and natural materials (e.g., geotextile overlying high hydraulic conductivity

sand drainage layer). Requirements for minimum hydraulic conductivity for granular and synthetic

materials are provided in Table 8.

CONSTRUCTION CONSIDERATIONS: CDF liner construction differs in many ways from

construction methods used for solid and hazardous waste landfills, due to the high water content of

dredged material, remote and sometimes difficult site accessibility, and potential low trafficability of the

working surface. Liner construction must also consider the future employment of other CDF control

systems, including lateral containment and cover systems, as well as costs. Further, CDF liner systems