1、Designation: D 4452 06Standard Practice forX-Ray Radiography of Soil Samples1This standard is issued under the fixed designation D 4452; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenth
2、eses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers the determination of the quality ofsoil samples in thin wall tubes or of extruded cores by X-rayradiography.1.2 This practice ena
3、bles the user to determine the effects ofsampling and natural variations within samples as identified bythe extent of the relative penetration of X-rays through soilsamples.1.3 This practice can be used to X-ray cores (or observetheir features on a fluoroscope) in thin wall tubes or linersranging fr
4、om approximately 2 to 6 in. (51 to 152 mm) indiameter. X-rays of samples in the larger diameter tubesprovide a radiograph of major features of soils and distur-bances, such as large scale bending of edges of varved clays,shear planes, the presence of large concretions, silt and sandseams thicker tha
5、n 1/4 in. (6.4 mm), large lumps of organicmatter, and voids or other types of intrusions. X-rays of thesmaller diameter cores provide higher resolution of soil fea-tures and disturbances, such as small concretions (1/8 in. (3.2mm) diameter or larger), solution channels, slight bending ofedges of var
6、ved clays, thin silt or sand seams, narrow solutionchannels, plant root structures, and organic matter. TheX-raying of samples in thin wall tubes or liners requiresminimal preparation1.4 Greater detail and resolution of various features of thesoil can be obtained by X-raying of extruded cores, ascom
7、pared to samples in metal tubes. The method used forX-raying cores is the same as that for tubes and liners, exceptthat extruded cores have to be handled with extreme care andhave to be placed in sample holders (similar to Fig. 2) beforeX-raying. This practice should be used only when naturalmoistur
8、e or other undisturbed soil characteristics are irrelevantto the end use of the sample.1.4.1 Often it is necessary to obtain greater resolution offeatures to determine the propriety of sampling methods, therepresentative nature of soil samples, or anomalies in soils.This practice requires that eithe
9、r duplicate samples be obtainedor already tested specimens be X-rayed.1.5 This practice can only be used to their fullest extent afterconsiderable experience is obtained through many detailedcomparisons between the X-ray film and the sample X-rayed.1.6 The values stated in inch-pound units are to be
10、 regardedas the standard. The SI values given in parentheses areprovided for information purposes only.1.7 This practice offers a set of instructions for performingone or more specific operations. This document cannot replaceeducation or experience and should be used in conjunction withprofessional
11、judgment. Not all aspects of this practice may beapplicable 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
12、many unique aspects. The word “Standard” in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.1.8 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
13、 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecaution statements, see Section 6.2. Referenced Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 3740 Pra
14、ctice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and ConstructionE7 Terminology Relating to Metallography3. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to soil samples, referto Terminology D 653.3
15、.1.2 For definitions of terms relating to X rays, refer toDefinitions E7.1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and are the direct responsibility of Subcommittee D18.07 on Identification andClassification of Soils.Current edition approved Nov. 1, 2006. Publish
16、ed January 2007. Originallyapproved in 1985. Last previous edition approved in 2002 as D 445285(2002)e1.2For 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 standard
17、s Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Significance and Use4.1 Many geotechnical tests require the utilization o
18、f undis-turbed, representative samples of soil deposits. The quality ofthese samples depends on many factors. Many of the samplesobtained by undisturbed sampling methods have inherentanomalies. Sampling procedures cause disturbances of varyingtypes and intensities. These anomalies and disturbances,
19、how-ever, are not always readily detectable by visual inspection ofthe undisturbed samples before or after testing. Often testresults would be enhanced if the presence and the extent ofthese anomalies and disturbances are known before testing orbefore destruction of the sample by testing. Such deter
20、mina-tions assist the user in detecting flaws in sampling methods, thepresence of natural or induced shear planes, and the presenceof natural intrusions, such as gravels or shells at critical regionsin the samples, the presence of sand and silt seams, and theintensity of some of the unavoidable dist
21、urbances caused bysampling.4.2 X-ray radiography provides the user with a picture ofthe internal massive structure of the soil sample, regardless ofwhether the soil is X-rayed within or without the samplingtube. X-ray radiography assists the user in identifying thefollowing:4.2.1 Appropriateness of
22、sampling methods used,4.2.2 Effects of sampling in terms of the disturbancescaused by the turning of the edges of various thin layers invarved soils, large disturbances caused in soft soils, shearplanes induced by sampling, or extrusion, or both, effects ofoverdriving of samplers, the presence of cu
23、ttings in samplingtubes, or the effects of using bent, corroded, or nonstandardtubes for sampling,4.2.3 Naturally occurring fissures, shear planes, and the like,4.2.4 The presence of intrusions within the sample, such ascalcareous nodules, gravel, or shells, and4.2.5 Sand and silt seams, organic mat
24、ter, large voids, andchannels developed by natural or artificial leaching of soilscomponents.NOTE 1The quality of the results produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteri
25、a of Practice D 3740 are generally cojsidered capable of competentand objective testing/sampling/inspection/and the like. Users of thismethod are cautioned that compliance with Practice D 3740 does not initself assure reliable testing. Reliable testing depeds on many factors;Practice D 3740 provides
26、 a means of evaluating some of those factors.5. Apparatus5.1 X-Ray Radiography EquipmentThe equipment shallhave a minimum output voltage of 100 kV. Equipment with apeak current of approximately 15 mA is needed for a widerange of applications capable of accommodating commerciallyavailable film, suita
27、ble for the sample sizes to be X-rayed, andsuitable for the sample holders. The equipment may beequipped with a fluoroscope.NOTE 2Certain types of samples may require equipment capable ofperforming at lower voltages (for example, 40 kV). In such instances,equipment with lower voltages can be substit
28、uted for that required in 5.1.For maximum resolution in certain types of applications a fine-focusX-ray tube may be necessary. Persons inexperienced with X-ray radiog-raphy should discuss their specific equipment needs and the requirementsof these methods with equipment manufacturers prior to purcha
29、sing.NOTE 3Equipment with berryllium window X-ray tubes may benecessary to perform radiography at low voltages.5.2 Solid Slice Trough, as shown in Fig. 1 or, other suitabletrough.5.3 Extruded Tube Sample Holder, as shown in Fig. 2,orother suitable holders.5.4 Thin Wall Tube Holders, as shown in Fig.
30、 3, or othersuitable holders.5.5 Measuring Tape, minimum 36 in. (914 mm) long.5.6 Personal Dosimeters or Film Badges.5.7 Small Hand Tools, such as wire saws, spatulas, andknives.5.8 Industrial Type X-Ray Film, or equivalent.5.9 Intensifying Screens, made of sheets of thin lead.5.10 Alphanumeric Lead
31、 Markers.h =d12 in. (12.7 mm)d = diameter of the sample to be slicedL = varies to suit sample lengthFIG. 1 Soil Slice Trough and HolderL = variable length to suit the length of the sampled = inside diameter of sampling tube usedW =d+2in.(51mm)H =d+0.25in.(6.4mm)FIG. 2 Extruded Tube Sample HolderD445
32、20626. Safety Precautions6.1 Radiation safety and policies for the use of X-rayradiography machines applicable to these methods should beestablished based on federal, state, and institutional require-ments meeting acceptable radiation safety standards, such asthose established by the National Counci
33、l on Radiation Pro-tection and Measurements (NCRP).37. Procedures7.1 Tubes and Liners7.1.1 Place the thin wall tube or liner holding the soilsample in the appropriate size sample holder, such as the oneshown in Fig. 3. If such a holder is not available, pack the tubesample in sand, clay, or plaster
34、of paris, forming an approxi-mately rectangular cross-section, as shown in Fig. 3.7.1.2 Load suitable X-ray film. Place the intensifying leadscreen in contact with the film.7.1.3 Position the sample and adjust the equipment so thatthe distance from the X-ray source to the film provides the bestpossi
35、ble radiograph. Experience has shown that a distance ofnot less than 30 in. (762 mm) is appropriate for most samples.Place the alphanumeric lead identification markers next to, oron, the portion of the sample that was closest to the groundsurface in situ that will be included in the X ray. If more t
36、hanone exposure is required to cover the entire length of thesample, a lead marker should be placed to serve as a matchmark.7.1.4 Adjust the output to a level which will provide theclearest radiograph or fluoroscopic image of the sample. Theoutput is to be determined by the user.7.1.5 Expose the fil
37、m an appropriate length of time. Processthe exposed film following film developing methods recom-mended by the manufacturer. The exposure time may vary withequipment, type of soil, or type of tubing material used. It isadvisable to experiment with the exposure time, keeping thedistance of the specim
38、en from film constant until well-defined,clear, X-ray radiographs are obtained. Adjustments also can bemade by keeping the exposure time constant and by varying thedistance of the X-ray source from the film.7.1.6 Rotate the sample 90 about its longitudinal axis andrepeat the procedure. Identify the
39、0 and 90 exposures withlead markers.7.1.7 For some applications it may be sufficient to preparesamples as in 7.1.1-7.1.3 and simply observe various featureson the fluoroscope; in such cases, eliminate 7.1.4.7.2 Extruded Samples7.2.1 Specimen Preparation:7.2.1.1 Place the specimen horizontally on the
40、 soil slicingtrough.7.2.1.2 Slice the specimen using a clean wire saw or otheracceptable cutting device.7.2.1.3 Remove the top portion of the specimen by placinga 180 segment of appropriate diameter thin wall tube over thespecimen. Turn the thin wall tube segment, the specimen, andthe slicing trough
41、 upside down in unison, so that the slicedspecimen rests in the thin wall tube segment.7.2.1.4 Remove the slicing trough and the portion of thespecimen contained within. Discard the portion of the speci-men removed from the slicing trough.7.2.1.5 Wipe the slicing trough clean.7.2.1.6 Place the porti
42、on of the specimen held in the thinwall tube segment in the trough with the sliced plane facing up.7.2.1.7 Repeat 7.2.1.2.7.2.1.8 Place a14-in. (6.4-mm) thick window glass or clearacrylic plate over the exposed face of the sample.7.2.1.9 Holding the glass plate with one hand and thespecimen trough w
43、ith the other, turn the glass plate, thespecimen, and the trough over.7.2.1.10 Remove the trough and the portion of the specimenremaining within. This should leave a38-in. (9.5-mm) thicksoil slice specimen on the glass plate.7.2.2 Procedure:7.2.2.1 Load suitable X-ray film. Place the intensifying le
44、adscreen in contact with the film.7.2.2.2 Position the specimen and glass plate and adjust thedistance from the X-ray source to the film to provide theclearest radiograph. Place the alphanumeric lead identificationmarkers on the glass plate next to the specimen.7.2.2.3 Repeat 7.1.3 and 7.1.4.7.2.2.4
45、 If radiography is not required, see 7.1.7.8. Interpretation of Test Results8.1 The interpretation of X-ray radiographs must be done bypersonnel experienced in analyzing X-ray radiographs of soils.8.2 X-ray radiographs show variations in the ability ofX-rays to penetrate matter. These variations are
46、 exhibited asvarying shades of gray color burned on the X-ray film.8.3 The following factors can be discerned from the radio-graph:3See the National Council on Radiation Protection and Measurements ReportNo. 33, 1973; Report No. 49, 1976; and Report No. 51, 1977.L = variable length to suit the lengt
47、h of sampling tubeW =d+2in.(51mm)H =d+0.25in.(6.4mm)d = outside diameter of sampling tube usedNOTE 1Aluminum sheet or pipe section is optional. Samples in tubescan be placed in the box and sand can be packed around and under it toconform with the dimensions shown.FIG. 3 Thin Wall Tube HolderD4452063
48、8.3.1 VoidsOpen void spaces will show as dark dots, orspaces, or channels, depending on the shape of the void (Fig.4).8.3.2 BeddingHorizontal, inclined, or distorted beddingwill show as layers of various shades of gray easily identifiableas bedding (Fig. 4).8.3.3 Turning of EdgesTurning or bending o
49、f edges ofvarious thin layers show as curved down edges on the sides ofthe specimen (Fig. 5). In extreme cases this turning down isaccompanied by a symmetrical curving of the distorted layers.This may be an indication of improper sampling or extrusionmethods (Fig. 6).8.3.4 Peat, Organic Matter, RootsPeat and organic matterwill appear as dark or black spots (Fig. 7), while roots willappear as black, irregular, often interconnected lines (Fig. 8).8.3.5 Shells and InvertebratesThey will appear as lightcolored shapes, generally easily identified from their profile(Fig.
