1、Designation: D6951/D6951M 09 (Reapproved 2015)D6951/D6951M 18Standard Test Method forUse of the Dynamic Cone Penetrometer in ShallowPavement Applications1This standard is issued under the fixed designation D6951/D6951M; the number immediately following the designation indicates theyear of original a
2、doption 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.1. Scope1.1 This test method covers the measurement of the penetration rate of th
3、e Dynamic Cone Penetrometerdynamic conepenetrometer with an 8-kg 17.6-lb hammer (8-kg 17.6-lb DCP) through undisturbed soil or compacted materials, or both. Thepenetration rate may be related to in situ strength such as an estimated in situ CBR (California Bearing Ratio). A soil density maybe estima
4、ted (Note 1) if the soil type and moisture content are known. The DCP described in this test method is typically used forpavement applications.1.2 The test method provides for an optional 4.6-kg 10.1-lb sliding hammer when the use of the 8-kg 17.6-lb sliding massproduces excessive penetration in sof
5、t ground conditions.1.3 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. The values statedin each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining valuesfrom the two systems may res
6、ult in non-conformancenonconformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and
7、 determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendat
8、ions issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D7380 Test Method for Soil Compaction Determination at Shallow Depths Using 5-lb (2.3 kg) Dynamic Cone Penetrometer3. Terminology3.1 Definitions of Terms Specific to This
9、 Standard:Definitions:3.1.1 8-kg 17.6-lb DCP dynamic cone penetrometer with an 8-kg 17.6-lb hammer penetrometer, (see nFig. 1)a devicewith an 8-kg 17.6-lb hammer used to assess the in situ strength of undisturbed soil or compacted materials, or both.both, bydropping the hammer from a set height and
10、measuring the depth of penetration and counting hammer drops (blows). (See Fig. 1.)3.1.2 sliding attachment, (see nFig. 1)an optional device used in reading the distance the DCP tip has penetrated. It maybe fastened to the anvil or lower rod to hold/slide along a separate measuring rod, or it may be
11、 fastened to the separate rod andslide along a graduated drive rod. (See Fig. 1.)4. Summary of Test Method4.1 The operator drives the DCP tip into soil by lifting the sliding hammer to the handle and then releasing it. The totalpenetration for a given number of blows is measured and recorded in mm/b
12、low, which is then used to describe stiffness, estimatean in situ CBR strength from an appropriate correlation chart, or other material charcharacteristics.characteristics.1 This test method is under the jurisdiction ofASTM Committee E17 on Vehicle - Pavement Systems and is the direct responsibility
13、 of Subcommittee E17.41 on PavementTesting and Evaluation.Current edition approved May 1, 2015May 1, 2018. Published July 2015May 2018. Originally approved in 2003. Last previous edition approved in 20092015 asD6951/D6951M 09.D6951/D6951M 09 (2015). DOI: 10.1520/D6951_D6951M-09R15.10.1520/D6951_D695
14、1M-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended o
15、nly to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current ver
16、sionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This test method is used to assess in situ strength of undisturbed soil and
17、compacted materials (or both). The penetrationrate of the 8-kg 17.6-lb DCP can be used to estimate in-situ in situ CBR (California Bearing Ratio), to identify strata thickness,shear strength of strata, and other material characteristics.5.1.1 Other test methods exist for DCPs with different hammer w
18、eights and cone tip sizes, which have correlations that areunique to the instrument.instrument, such as Test Method D7380.5.2 The 8-kg 17.6-lb DCP is held vertically, and therefore is typically used in horizontal construction applications, such aspavements and floor slabs.5.3 This instrument is typi
19、cally used to assess material properties down to a depth of 1000 mm 39 in. below the surface. Thepenetration depth can be increased using drive rod extensions. However, if drive rod extensions are used, care should be takenwhen using correlations to estimate other parameters, since these correlation
20、s are only appropriate for specific DCPconfigurations.The mass and inertia of the device will change and skin friction along drive rod extensions will occur.5.4 The 8-kg 17.6-lb DCP can be used to estimate the strength characteristics of fine- and coarse-grained soils, granularconstruction materials
21、, and weak stabilized or modified materials. The 8-kg 17.6-lb DCP cannot be used in highly stabilized orcemented materials or for granular materials containing a large percentage of aggregates greater than 50 mm 2 in.5.5 The 8-kg 17.6-lb DCPcan be used to estimate the strength of in situ materials u
22、nderlying a bound or highly stabilized layerby first drilling or coring an access hole.FIG. 1 Schematic of DCP DeviceD6951/D6951M 182NOTE 1The DCP may be used to assess the density of a fairly uniform material by relating density to penetration rate on the same material. In thisway, undercompacted o
23、r “soft spots”“soft” spots can be identified, even though the DCP does not measure density directly.34.5.1 A field DCP measurement results in a field or in situ CBR and will not normally correlate with the laboratory or soakedCBR of the same material. The test is thus intended to evaluate the in sit
24、u strength of a material under existing field conditions.5.6 Afield DCPmeasurement results in a field or in situ CBR and will not normally correlate with the laboratory or soaked CBRof the same material. The test is thus intended to evaluate the in situ strength of a material under existing field co
25、nditions.6. Apparatus6.1 The 8-kg 17.6-lb DCPis shown schematically in Fig. 1. It consists of the following components: a 16-mm 58-in. diametersteel drive rod with a replaceable point or disposable cone tip, an 8-kg 17.6-lb hammer which is dropped from a fixed height of575 mm 22.6 in., a coupler ass
26、embly, and a handle. The tip has an included angle of 60 degrees 60 and a diameter at the baseof 20 mm 0.79 in. (See Fig. 2.)6.1.1 The apparatus is typically constructed of stainless steel, with the exception of the replacement point tip, which may beconstructed from hardened tool steel or a similar
27、 material resistant to wear.6.2 The following tolerances are recommended:required:6.2.1 Hammer weight-measurement weight measurement of 8.0 kg 17.6 lb; tolerance is 0.01 kg 0.02 lb,6.2.2 Hammer weight-measurement weight measurement of 4.6 kg 10.1 lb.; tolerance is 0.01 kg 0.02 lb,6.2.3 Drop of hamme
28、r-measurement hammer measurement of 575 mm 22.6 in.; tolerance is 1.0 mm 0.04 in.,6.2.4 Tip angle measurement of 60 degrees 60 included angle; tolerance is 1 degree, 1, and6.2.5 Tip base diameter measurement of 20 mm 0.79 in.; tolerance is 0.25 mm 0.01 in.in.NOTE 2A disposable cone tip may be used.
29、The deposabledisposable cone tip is held in place with an o-ring,O-ring, which allows the cone tip tobe easily detached when the drive rod is pulled upward after completion of the test. The disposable cone tip is shown schematically in Fig. 3.6.3 In addition to the DCP, the following equipment is ne
30、eded:6.3.1 Tools for assembling the DCP,6.3.2 Lubricating Oil,oil,6.3.3 Thread Locking Compound,locking compound, and6.3.4 Data Recordingrecording form (see Table 1).6.4 Depending on the circumstances, the following equipment may also be needed or is recommended:6.4.1 A vertical scale graduatedscale
31、, graduated, using increments of 1.0 mm 1.0 mm 0.04 in., or measuring rod longer thanthe longest drive rod if the drive rod(s) are not graduated,6.4.2 An optional sliding attachment for use with a separate scale or measuring rod,6.4.3 A rotary hammer drill or coring apparatus capable of drilling a m
32、inimum diameter hole of 25 mm 1 in. A larger holemay be required, depending on the underlying material or the need for addition tests or sampling,6.4.4 A wet/dry vacuum or suitable alternative to remove loose material and fluid if an access hole is made before testing,6.4.5 Field power supply to pow
33、er items in 5.4.36.4.3 and 5.4.46.4.4,6.4.6 Disposable cone tips,3 “METHOD ST6: Measurement of the In Situ Strength of Soils by the Dynamic Cone Penetrometer (DCP), Special Methods for Testing Roads,” Draft TMH6, TechnicalMethods for Highways (TMH), Pretoria, South Africa, ISBN 0 7988 2289 9, 1984,
34、p. 20.FIG. 2 Replaceable Point TipD6951/D6951M 1836.4.7 Dual mass Dual-mass hammer (see Fig. 4), and6.4.8 Extraction jack, recommended if disposable cone tips are not used (see Fig. 5).NOTE 3A4.6-kg 10-lb10.1-lb hammer (see Fig. 4) may be used in place of the 8-kg 18-lbf hammer17.6-lb hammer, provid
35、ed that the standarddrop height is maintained. The 4.6-kg 10-lbf10.1-lb hammer is used in weaker materials where the 8-kg 18-lbf17.6-lb hammer would produceexcessive penetration.NOTE 4An automated version of the DCP(ADCP) may be used, provided all requirements of this standard with respect to the ap
36、paratus and procedureare met.NOTE 5An automated data collection system may be used, provided it measures and records to the nearest 1 mm 0.04 in. and does not interferewith the operation/results of the devise.device.7. Hazards7.1 Be aware and maintain control of the hammer during movement of the dev
37、ice prior to and after testing to prevent pinch pointinjuries.7.2 Always secure the hammer or the assembled DCP device, or both, when placing it on a flat, elevated surface to prevent itfrom rolling off and causing personal injury or damage to the instrument.7.3 Do not put hands near the anvil when
38、the hammer is raised. Keep one hand on the handle while operating the DCP.8. Preparation of Apparatus8.1 Equipment CheckBefore beginning a test, the DCPdevice is inspected for fatigue-damaged parts, in particular the couplerand handle, and excessive wear of the drive rod and replaceable point tip. D
39、rive rods should be visually inspected for straightness;rolling it on a flat surface can aid in detecting a bent rod.8.2 All joints must be securely tightened, including the coupler assembly and the replaceable point tip (or the adapter for thedisposable cone tip) to drive rod. It is recommended usi
40、ng wrenches to tighten all joints to prevent damage to the threads in thejoints. Channel lock or similar pliers are not recommended.9. Procedure6.1 Equipment CheckBefore beginning a test, the DCPdevice is inspected for fatigue-damaged parts, in particular the couplerand handle, and excessive wear of
41、 the drive rod and replaceable point tip. All joints must be securely tightened including thecoupler assembly and the replaceable point tip (or the adapter for the disposable cone tip) to drive rod.9.1 Basic OperationThe operator holds the device by the handle in a vertical or plumb position and lif
42、ts and releases thehammer from the standard drop height. The recorder measures and records the total penetration for a given number of blows orthe penetration per blow.9.2 Initial Reading:9.2.1 Testing a Surface LayerThe DCP is held vertically and the tip seated such that the top of the widest part
43、of the tip isflush with the surface of the material to be tested. An initial reading is obtained from the graduated drive rod or a separate verticalscale/measuring rod. The distance is measured to the nearest 1 mm 0.04 in. Some sliding reference attachments allow thescale/measuring rod to be set/mar
44、ked at zero when the tip is at the zero point shown in Fig. 2Figs. 2 and 3.9.2.2 Testing Below a Bound LayerWhen testing materials underlying a bound layer, a rotary hammer drill or coring apparatusmeeting the requirements given in 5.4.36.4.3 above is used to provide an access hole to the layer to b
45、e tested. Wet coring requiresthat coring fluid be removed immediately and the DCPtest be performed as soon as possible, but not longer than 10 minutes 10 minfollowing completion of the coring operation. The coring fluid must not be allowed to soak into or penetrate the material to betested. A wet/dr
46、y vacuum or suitable alternative is used after completion of drilling or coring to remove loose materials and fluidfrom the access hole before testing. To minimize the extent of the disturbance from the rotary hammer, drilling should not be takenFIG. 3 Disposable Cone TipD6951/D6951M 184completely t
47、hrough the bound layer, but stopped short by about 10 to 20 mm 0.4 to 0.8 in. The DCP is then used to penetratethe bottom portion of the bound layer. This can be a repetitive process between drilling and doing DCP tests to determine thethickness of the layer.9.2.3 Testing Pavement Withwith Thin Seal
48、sFor pavements with thin seals, the tip is advanced through the seal until the zeropoint (see Fig. 4Figs. 2 and 3) of the tip is flush with the top of the layer to be tested.9.2.4 Once the layer to be tested has been reached, a reference reading is taken with the zero point at the top of that layer
49、andthe thickness of the layer(s) cored through recorded. This reference reading is the point from which the subsequent penetration ismeasured.9.3 Testing Sequence:9.3.1 Dropping the HammerThe DCP device is held in a vertical or plumb position. The operator raises the hammer until itmakes only light contact with the handle. The hammer shall not impact the handle when being raised. The hammer is then allowedto free-fall free fall and impact the anvil coupler assembly. Th
