1、Designation: D 6066 96 (Reapproved 2004)Standard Practice forDetermining the Normalized Penetration Resistance ofSands for Evaluation of Liquefaction Potential1This standard is issued under the fixed designation D 6066; the number immediately following the designation indicates the year oforiginal a
2、doption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice outlines a procedure to obtain a record ofnormalized r
3、esistance of sands to the penetration of a standardsampler driven by a standard energy for estimating soilliquefaction potential during earthquakes. The normalizedpenetration resistance determined in this practice may be usefulfor determination of other engineering properties of sands.1.2 This pract
4、ice uses Test Method D 1586 with additionsand modifications to minimize disturbance of saturated loosecohesionless sands during drilling. This practice combinesresults of Test Method D 1586 and interprets the data fornormalization purposes.1.3 Due to inherent variability of the SPT, guidance is give
5、non test configuration and energy adjustments. Penetrationresistance is adjusted for energy delivered in the penetrationtest. Energy adjustments can be estimated or measured andreported.1.4 Standard practice for normalizing penetration resistancevalues is given. Penetration resistance data are norma
6、lized to astandard overburden stress level.1.5 The normalized penetration resistance data may be usedto estimate liquefaction resistance of saturated sands fromearthquake shaking. Evaluation of liquefaction resistance maybe applied to natural ground conditions or foundations foreither planned or exi
7、sting structures.1.6 Using this practice representative disturbed samples ofthe soil can be collected for identification purposes.1.7 This practice is limited to use in cohesionless soils (seeTest Method D 2487 and classifications of SM, SW, SP,SP-SM, and SW-SM Practice D 2488). In most cases, testi
8、ng isperformed in saturated deposits below the water table. In somecases, dry sands may be tested (see 5.4). This practice is notapplicable to lithified materials or fine grained soils. Gravel caninterfere with the test and result in elevated penetrationresistance values. Normalization of penetratio
9、n resistance val-ues for gravelly soils is beyond the scope of this practice.1.8 Penetration resistance measurements often will involvesafety planning, administration, and documentation. This prac-tice does not purport to address all aspects of exploration andsite safety. This standard does not purp
10、ort 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. Performance of thetest usually involves use o
11、f a drill rig; therefore, safetyrequirements as outlined in applicable safety standards. Forexample, OSHA regulations,2DCDMA safety manual,3drill-ing safety manuals, and other applicable state and localregulations must be observed.1.9 The values stated in inch-pound units are to be regardedas standa
12、rd. Within the text, the SI units, are shown inparentheses. The values stated in each system are not equiva-lents, therefore, each system must be used independently of theother.1.9.1 In pressure correction calculations, common units areton/ft2, kg/cm2, atm, and bars. Since these units are approxi-ma
13、tely equal (within a factor of 1.1), many engineers prefer theuse of these units in stress correction calculations. For thoseusing kPa or kN/m2, 100 kPa is approximately equal to oneton/ft2. The stress exponent, n, (see 3.3.1) is approximatelyequal for these units.1.10 This practice may not be appli
14、cable in some countries,states, or localities, where rules or standards may differ forapplying penetration resistance to liquefaction estimates. Otherpractices exist for estimating soil instability from penetrationresistance data. Procedures may change with advances ingeotechnical engineering. It is
15、 dependent on the user inconsultation with experienced engineers to select appropriatemethods and correction to data. In earthquake engineeringstudies, many phenomena can affect soil instability. Thepractice reflects only one current exploration technique andmethod for normalizing penetration resist
16、ance data to a com-mon level for comparisons to case history information.1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.02 on Sampling andRelated Field Testing for Soil Evaluations.Current edition approved Nov. 1, 2
17、004. Published January 2005. Originallyapproved in 1996. Last previous edition approved in 1996 as D606696e1.2Available from OSHA, 1825 K. Street, NW, Washington, DC 20006.3Available from the Drilling Equipment Manufacturers Association, 3008Millwood Avenue, Columbia, SC 29205.1Copyright ASTM Intern
18、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1.11 This practice offers a set of instructions for performingone or more specific operations. This document cannot replaceeducation or experience and should be used in conjunctionwith professional judgment.
19、 Not all aspects of this practice maybe applicable in all circumstances. This ASTM standard is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,nor should this document be applied without consideration ofa projects many uniq
20、ue aspects. The word “Standard” in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.2. Referenced Documents2.1 ASTM Standards:4D 653 Terminology Relating to Soil, Rock and ContainedFluidsD 1586 Test Method for Penetration Test and Split-Barre
21、lSampling of SoilsD 2216 Method for Laboratory Determination of Water(Moisture) Content of Soil and RockD 2487 Classification of Soils for Engineering PurposesUnified Soil Classification SystemD 2488 Practice for Description and Identification of Soils(Visual Manual Procedure)D 3740 Practice for Min
22、imum Requirements for AgenciesEngaged in the Testing or Inspection of Soil and Rock, orboth, as Used in Engineering Design and ConstructionD 4633 Test Method for Stress Wave Energy Measurementfor Dynamic Penetrometer Testing SystemsD 5434 Guide for Field Logging of Subsurface Explora-tions of Soil a
23、nd RockD 5778 Performing Electronic Friction Cone and PiezoconePenetration Testing of Soil3. Terminology3.1 DefinitionsDefinitions of terms included in Terminol-ogy D 653 specific to this practice are:3.1.1 effective stressthe average normal force per unitarea transmitted from grain to grain of a so
24、il mass (see 13.4.1).3.1.2 equilibrium pore water pressure, uoat rest waterpressure at depth of interest. Same as hydrostaic pressure (see13.4.1.1).3.1.3 liquefactionthe process of transforming any soilfrom a solid state to a liquid state, usually as a result ofincreased pore pressure and reduced sh
25、earing resistance.3.1.4 standard penetration resistance, Nthe number ofblows of a 140 lbm (63.5 kg) hammer falling 30 in. (76 cm)required to produce1fofpenetration of a specified (standard)2-in. outside diameter, 138-in. inside diameter sampler intosoil, after an initial 0.5 f seating.3.2 Definition
26、s of Terms Specific to This Standard:3.2.1 anvil, nthat portion of the drive assembly that thehammer strikes and through which the hammer energy istransmitted into the drill rods.3.2.2 automatic hammer, na hammer drop system thatuses mechanical means to lift and control drop height of thehammer.3.2.
27、3 cathead, na spinning sheave or rotating drumaround which the operator wraps the rope used to lift and dropthe hammer by successively tightening and loosening the ropeturns around the drum.3.2.4 cleanout depth, ndepth that the bottom of thecleanout tool (end of drill bit or cutter teeth) reaches be
28、foretermination of cleanout procedures.3.2.5 cleanout interval, ninterval between successivepenetration resistance tests from which material must beremoved using conventional drilling methods. During theclean-out process, the previous penetration test interval (1.5 ft,45 cm) is drilled through and a
29、dditional distance is cleaned toassure minimal disturbance of the next test interval. The termclean out interval in this practice refers to the additionaldistance past the previous test.3.2.6 crown blocka pulley, set of pulleys, or sheaves at thetop of the drill derrick or mast on or over which the
30、hoist orother lines, or both, run.3.2.7 cylinder hammer, ndrive weight assembly consist-ing of a guide pipe, anvil, jar coupling, and an open cylindricalhammer. Also called a donut or casing hammer.3.2.8 downhole hammer, na hammer lowered down thedrill hole and attached a short distance above the sa
31、mpler.3.2.9 donut hammer, nsee cylinder hammer.3.2.10 drill rods, nrods used to transmit downward androtary force to the sampler or drill bit.3.2.11 drill rod energy ratio, ERi(see Test Method D 4633),nmeasured stress wave energy ratio. The ratio is that ofenergy measured in drill rods contained in
32、the first compressionwave to nominal energy of the drive weight system.3.2.12 drive interval, ninterval from 0.0 to 1.5 ft (45 cm)below the cleanout depth that consists of the 0.5 ft (15 cm)seating and the 1.0 ft (30 cm) test interval.3.2.13 drive length, ntotal length of the drive intervalpenetrate
33、d during testing, that is, the measured distance thesampler is actually advanced.3.2.14 drive weight assembly, nan assembly that consistsof the hammer, anvil, hammer fall guide system, drill rodattachment system, and any hammer drop system hoistingattachments.3.2.15 hammer, nthat portion of the driv
34、e weight assem-bly consisting of the 140-lbm impact mass that is liftedsuccessively and dropped to provide the energy that accom-plishes the penetration and sampling.3.2.16 hammer drop system, nthat portion of the driveweight assembly by which the operator accomplishes thelifting and dropping of the
35、 hammer to produce the blow.3.2.17 number of rope turns, nthe number of times a ropeis wrapped completely around the cathead. Penetration resis-tance testing is performed using two nominal rope turns on thecathead. Depending on operator position, direction of catheadrotation, and the angle at which
36、the rope leaves the cathead, theactual number of turns typically varies from 134 to 214 turns(Fig. 1).4For 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
37、Document Summary page onthe ASTM website.D 6066 96 (2004)23.2.18 rope, cathead method, na method of raising anddropping the hammer, which uses a rope strung through acenter crown sheave or pulley on the drill mast and turns on acathead to lift the hammer.3.2.19 safety hammer, ndrive weight assembly
38、consistingof a center guide rod, internal anvil, and hammer that enclosesthe hammer-anvil contact (Fig. 2).3.2.20 seating interval, ninterval from 0.0 to 0.5-ft (0 to15 cm) below the cleanout depth.3.2.21 test interval, ninterval from 0.5 to 1.5 ft (15 to 45cm) below the cleanout depth.3.2.22 trip h
39、ammers, nhammers hoisted by rope-catheadmethod and mechanically released for a drop without ropeattached.3.2.23 vertical effective stress, n, s8vthe average effectiveforce per unit area transmitted from grain to grain of a soilmass normal to the horizontal plane (see 13.4.1 for calcula-tion).3.3 Abb
40、reviations:Symbols and Abbreviations:3.3.1 nstress exponent in the equation:CN5 s8vref/s8v!n(1)where:s8vref= reference stress level,s8v= vertical effective stress at test depth,s8vref= 1 tsf (1kgf/cm2, 1 bar, 1 atm), andCn= 1/(s8v)n.3.3.2 N valuethe sum of the hammer blows required todrive the sampl
41、er over the test interval from 0.5 to 1.5 ft (15 to45 cm) below the cleanout depth.3.3.3 N60penetration resistance adjusted to a 60 % drillrod energy ratio (see 13.3.2).3.3.4 (N1)60penetration resistance adjusted for energy andstress level.3.3.5 SPTabbreviation for standard penetration test ofpenetr
42、ation resistance testing.4. Summary of Practice4.1 Drilling is performed with minimal disturbance to ad-vance a boring to the test interval. For loose sand, specificmeasures and quality checks may be required to assureminimal disturbance. If disturbance is evident, an alternatedrilling method may be
43、 required.4.2 After an initial seating drive of 0.5 ft (15 cm), a standardpenetration resistance sampler is driven 1.0 ft (30 cm) into soilbelow the bottom of a drill hole using a 140-lbm hammer,dropped 30 in. (75 cm). Penetration resistance, N, is expressedas the number of hammer blows required to
44、drive the samplerthe 1.0-ft (30-cm) distance.4.3 In Method A, the penetration resistance is adjusted to adrill rod energy ratio of 60 %, N60, by using hammer systemswith an estimated energy delivery. Safety hammers withrope-cathead operation are assumed to deliver approximately60 % drill rod energy
45、(Eri 60 %). Automatic hammer energymust be documented in previous measurements for a particularmake and model, either by the manufacturer or from previousmeasurements by other entities.4.4 In Method B, penetration resistance data is adjusted to60 % drill rod energy ratio through directly measured dr
46、ill rodstress wave energy using Test Method D 4633 or other docu-mented procedures. The adjustment can be made to the N valuefor a particular hammer system or the hammer system may beadjusted to deliver 60 % drill rod energy (see 6.4.2).4.5 The N60value is normalized to an effective overburdenpressu
47、re of 1-tsf (1 kg/cm2, bar, atm) using overburdenpressure correction factors from chamber tests. Typical adjust-ment factors are given to the user (see 13.4). The user mayadjust the factors depending on the nature of the foundationsoils, such as, previous stress history, particle size.FIG. 1 Number
48、of Rope Turns on CatheadFIG. 2 Internal Anvil Safety HammersTypical DesignsD 6066 96 (2004)35. Significance and Use5.1 Normalization of penetration resistance data is a fre-quently used method to evaluate the liquefaction susceptibilityof sands.Alarge case history database from many countries hasbee
49、n accumulated to estimate instability of saturated sandsduring earthquakes (1,2,3,4).5This test is used extensively fora great variety of geotechnical exploration programs whereearthquake induced instability of soil needs to be evaluated.Many widely published correlations and local correlations areavailable, which relate penetration resistance to the engineer-ing properties of soils and the behavior of earthworks andfoundations. The data from different countries with differingdrilling techniques have been interpreted to develop a preferr
