ASTM_D_7498_-_D_7498M_-_09_2014e1.pdf

Designation:D7498/D7498M09(Reapproved 2014)1Standard Test Method forVertical Strip Drains Using a Large Scale ConsolidationTest1This standard is issued under the fixed designation D7498/D7498M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEUnits information and designation were corrected and editorial changes were made throughout in February 20141.Scope1.1 This test method is a performance test,which measuresthe effectiveness of vertical strip drains on the time rates ofconsolidation of compressible soils from construction projectsites.1.1.1 It is expected that the design agency will be respon-sible for performing this test.It is not intended to be amanufacturer performed test.1.2 This test method is applicable to all vertical strip drains.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs)for TestingD4439 Terminology for Geosynthetics3.Terminology3.1 DefinitionsFor definitions related to geosynthetics,seeTerminology D4439.3.2 Definitions of Terms Specific to This Standard:3.2.1 vertical strip drains,na geocomposite consisting ofa geotextile cover and drainage core installed vertically intosoil to provide drainage for accelerated consolidation of soils.4.Summary of Test Method4.1 This test method describes procedures for determiningthe effectiveness of vertical strip drains used under specifiedsoil conditions to enhance the time rate of consolidation ofcompressible soils.4.2 A specimen of the vertical strip drain is inserted in thetest chamber and compressible soil from the project site isremolded around the vertical strip drain,such that the drain isin a similar position as it would be on the project site.4.3 The top of the soil is sealed with a wax seal,such thatdrainage only occurs through the vertical strip drain.Thevertical strip drain protrudes up through the seal.4.4 Asand drainage blanket is placed on top of the wax seal,such that the vertical strip drain drains into the sand blanket.4.5 A rubber cup seal provides the means of applyingincremental loads in a similar manner to a standard soilsconsolidation test.4.6 A similar setup is used,only with a 50 mm 2 in.sanddrain in place of the vertical strip drain.4.7 The Coefficients of Consolidation are determined fromthe test results for both the vertical strip drain and the sanddrain.Time rates of consolidation are then compared.4.8 Persons performing this test shall have knowledge in theconsolidation testing of soils.5.Significance and Use5.1 As this is a time intensive test,it should not beconsidered as an acceptance test for commercial shipments ofprefabricated vertical strip drains.5.2 Prior to the development of vertical strip drains,when itwas desired to increase the rate of consolidation of a compress-ible soil on a construction project,large diameter sand drainswere installed.Vertical strip drains can be installed in areas1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.03 on Perme-ability and Filtration.Current edition approved Jan.1,2014.Published February 2014.Originallyapproved in 2009.Last previous edition approved in 2009 as D749809.DOI:10.1520/D7498_D7498M-09R14E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 where it is desired to increase the rate of soils consolidation inplace of these large diameter sand drains.5.3 This test method can be used to compare the perfor-mance of vertical strip drains to that of sand drains.6.Apparatus6.1 The apparatus for this test method is a specialty piece ofequipment that must be capable of safely handling loads up to206.8 kPa 30 psi using compressed air.6.1.1 As this is a time intensive test,it is recommended tohave three test apparatus setups.This will allow simultaneoustesting of three vertical strip drain specimens.6.1.2