1、Designation: D7380 15Standard Test Method forSoil Compaction Determination at Shallow Depths Using5-lb (2.3 kg) Dynamic Cone Penetrometer1This standard is issued under the fixed designation D7380; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the procedure for the determi-nation of the number of drops require
3、d for a dynamic conepenetrometer with a 5-lb (2.3-kg) drop hammer falling 20 in.(508 mm) to penetrate a certain depth in compacted backfill.1.2 The device is used in the compaction verification offine- and coarse-grained soils, granular materials, and weakstabilized or modified material used in subg
4、rade, base layers,and backfill compaction in confined cuts and trenches atshallow depth.1.3 The test method is not applicable to highly stabilizedand cemented materials or granular materials containing a largepercentage of aggregates greater than 1.5 in. (37 mm).1.4 The method is dependent upon know
5、ing the field watercontent and the user having performed calibration tests todetermine cone penetration resistance of various compactionlevels and water contents.1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI
6、 units that are provided for information onlyand are not considered standard.1.6 It is common practice in the engineering profession toconcurrently use pounds to represent both a unit of mass (lbm)and a force (lbf). This implicitly combines two separatesystems of units; that is, the absolute system
7、and the gravita-tional system. This standard has been written using thegravitational system of units when dealing with the inch-poundsystem. In this system, the pound (lbf) represents a unit of force(weight). However, the use of balances or scales recordingpounds of mass (lbm) or the reading of dens
8、ity in lbm/ft3shallnot be regarded as a nonconformance with this standard.1.7 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.8 This standard does not purport to address all of thesafety concerns, if any, associated
9、 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:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD69
10、8 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D1556 Test Method for Density and Unit Weight of Soil inPlace by Sand-Cone MethodD1557 Test Methods for Laboratory Compaction Character-istics of Soil Using Modified Effort (56,000 f
11、t-lbf/ft3(2,700 kN-m/m3)D2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4959 Test Method for Dete
12、rmination of Water (Moisture)Content of Soil By Direct HeatingD6026 Practice for Using Significant Digits in GeotechnicalDataD6938 Test Methods for In-Place Density and Water Contentof Soil and Soil-Aggregate by Nuclear Methods (ShallowDepth)D6951 Test Method for Use of the Dynamic Cone Penetrom-ete
13、r in Shallow Pavement ApplicationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsFor definitions of common technical termsused in this standard, refer to Terminology D653.1This test method is under the jurisdiction ofASTM
14、Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.08 on Special andConstruction Control Tests.Current edition approved Nov. 1, 2015. Published November 2015. Originallyapproved in 2008. Last previous edition approved in 2008 as D7380 - 08. DOI:10.1520/D7380-15.2For r
15、eferenced 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.*A Summary of Changes section appears at the end of this standardCo
16、pyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Definitions of Terms Specific to This Standard:3.2.1 5-lb dynamic cone penetrometer (5-lb DCP)(Fig. 1)a device that uses a 5-lb (2.3-kg) hammer to penetrate a conetip inside the soil w
17、here the number of drops needed topenetrate a certain distance between two marks on the drivingrod is used to determine soil compaction effort.3.2.2 extension rodin dynamic cone penetrometer, anoptional extension of the driving rod to allow the use of the5-lb DCP in deep confined holes.3.2.2.1 Discu
18、ssionThe extension rod has a sliding sleevewith two markers similar to the ones on the 5-lb DCP drivingrod for identifying the penetration distance and allowing thereadings to be taken near or at the surface of the hole.3.2.3 electronic readout unitin dynamic conepenetrometer, optional readout devic
19、e to automatically countthe number of hammer drops and penetration distance insidethe soil.4. Summary of Test Method4.1 The 5-lb DCP is placed vertically and the drop hammeris used to penetrate the soil until the lower mark on the drivingrod is leveled with the surface of the soil.4.2 The operator l
20、ifts the drop hammer to the upper stopdisk and releases it, allowing it to fall freely under gravity andstrike an anvil, causing the cone to be driven into the soil. Thenumber of drops needed to penetrate the cone a distance 3.25in. (83 mm) from the lower mark on the driving rod to theupper one is c
21、ounted.4.3 The number of drops is used to determine the pass or failof soil compaction based on the results of calibration testsbetween the number of drops and soil percent compaction insimilar soil of known percent compaction and water content.5. Significance and Use5.1 The test method is used to a
22、ssess the compaction effortof compacted materials. The number of drops required to drivethe cone a distance of 3.25 in. (83 mm) is used as a criterion todetermine the pass or fail in terms of soil percent compaction.5.2 The device does not measure soil compaction directlyand requires determining the
23、 correlation between the numberof drops and percent compaction in similar soil of knownpercent compaction and water content.5.3 The number of drops is dependent on the soil watercontent. Calibration of the device should be performed at awater content equal to the water content expected in the field.
24、5.4 There are other DCPs with different dimensions, ham-mer weights, cone sizes, and cone geometries. Different testmethods exist for these devices (such as D6951) and thecorrelations of the 5-lb DCP with soil percent compaction areunique to this device.5.5 The 5-lb DCP is a simple device, capable o
25、f beinghandled and operated by a single operator in field conditions. Itis typically used as Quality Control (QC) of layer-by-layercompaction by construction crew in roadway pavement, back-fill compaction in confined cuts and trenches, and utilitypavement restoration work.NOTE 1The quality of result
26、s produced by this test method isdependent on the competence of the personnel performing it and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of t
27、his standard arecautioned that compliance with Practice D3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of these factors.6. Apparatus6.1 Aschematic diagram of the 5-lb DCP is shown in Fig. 1.The device consis
28、ts of an1116 6116 in. (17.5 6 1.6 mm) steelrod with a 5 6 0.2 lb (2.3 6 0.1 kg) drop hammer. The hammerdrops a distance 20 6 0.4 in. (508 6 10 mm) between theupper stop plate and the anvil.6.2 Driving RodThe driving rod has two permanent marksor groves to monitor cone penetration depth. The lower ma
29、rk isat a distance 314 in. (83 mm) from the top surface of the coneand the distance between the two marks is 3.25 in. (83 mm).FIG. 1 Schematic Diagram of the 5-lb DCP DeviceD7380 1526.3 Cone TipA replaceable cone tip of hardened steel orsimilar material with angle 25 6 2 degrees is placed at thebott
30、om of the driving rod. Fig. 2 shows the dimensions of thecone tip.6.4 Extension RodAn extension rod may be used tomonitor compaction in deep cuts and narrow trenches wherethe operator has to work from the ground surface. Theextension rod should be of the same diameter and material asthe driving rod.
31、 Fig. 3 shows a schematic of the device with theextension rod used in a confined hole.6.5 When the device is used in small holes and trenches, asleeve is used to monitor the penetration distance from thesurface as shown in Fig. 3. The lower mark on the sleeve isleveled with the ground surface using
32、a straight edge and thesleeve is tightened by a screw to prevent it from moving duringthe test. Fig. 4 shows the dimensions of the sleeve.6.6 The addition of extensions will change the mass of thedevice and the energy delivered to the cone. When extensionrods and sleeves are used, calibration tests
33、should be performedwith these extensions attached to the device.6.7 An automated electronic data readout unit may be usedto register the number of drops and the penetrating distance.The system should give a signal and stop counting the numberof drops once the penetration equals the distance from the
34、lower mark to the top one.6.8 The optional automated data readout unit should notinterfere with the operation and results of the device. Theoutput data of the system should satisfy the requirements ofdata reporting in Section 9.7. Calibration7.1 Device preparationThe device shall be inspected fordam
35、aged parts before testing; the cone tip angle should not bedamaged and be within the acceptable tolerance before testing.7.2 Soil sample preparation:7.2.1 The soil percent compaction and optimum watercontent are determined for soil samples obtained from the fieldaccording to Test Method D698 or D155
36、7 for laboratorycompaction characteristics of soil as per the project compactionspecifications.7.2.2 A soil sample is obtained from the field to filla2ft(610 mm) wide by 2 ft long test pit with a depth of 12 in. (305mm). The test pit can be constructed in the site or in the lab.7.2.3 The soil is pla
37、ced in the pit within 62 % of itsoptimum water content or as specified in the project compac-tion specifications. The soil water content in the pit is deter-mined using Test Method D2216 or D6938.7.2.4 The soil is compacted in two lifts, 6 in. (150 mm) eachusing equal compaction effort in each lift.
38、 Initially, the soil iscompacted using a low compaction effort. The soil density ismeasured using Test Method D6938 or D1556.7.3 Setup of the coneThe operator holds the devicevertically by the handle over the soil surface then lifts the drophammer and releases it to cause the cone to penetrate until
39、 thelower mark on the driving rod is leveled with the surface of thesoil layer.7.4 Cone testingThe operator lifts the drop hammer to theupper stop disk and releases it, allowing it to fall freely undergravity. The hammer shall not unduly impact the upper diskwhen raised. The operator repeats the pro
40、cess and the numberof drops needed to advance the cone a distance 3.25 in. (83mm) is recorded.NOTE 2In stiff soils, where the number of drops between the marksexceeds 20 drops at low compaction, the setup of the DCP test can beperformed by dropping the hammer until only the top surface of cone(inste
41、ad of the lower mark) is leveled with the surface of the soil. Thetesting is then performed by counting the number of drops for the distanceof 3.25 in. (83 mm) between the top surface of the cone and the lowermark as shown in Fig. 1. Record the starting point of testing in the report.7.5 If the last
42、 drop needed to advance the cone 3.25 in. (83mm) overshoots the mark, then the last drop is not counted inthe total number of drops.7.6 The soil is removed from the test pit, replaced, andcompacted using higher compaction efforts at the same watercontent. Steps 7.3 to 7.7 are repeated at higher comp
43、actionefforts until the compaction exceeds the specified percentcompaction required in the field.7.7 The number of hammer drops at each soil density isplotted against the corresponding soil percent compaction asshown in Fig. 5. A minimum of four points should be used toestablish the calibration curv
44、e. At least one point should bewithin 2 % of the maximum percent compaction required in thefield.NOTE 3Calibration of the device should be performed on samplesrepresenting the field water content. Calibration should be repeated if thecalibration water content varies more than 62 % of the project sta
45、ndards.Calibration should also be performed when a new cone tip or a differenttip angle is used to replace a deteriorated one.8. Procedure8.1 Test site preparationRecord site information, backfilltype of each compacted lift, lift height, its optimum waterFIG. 2 Dimensions of the Cone TipD7380 153con
46、tent, and target percent compaction based on the standardor modified compaction tests in the lab.8.2 Verify and record field water content using Test MethodD2216 or D4959.8.3 Field testing at gradeThe operator performs steps 7.3to 7.7 as in the calibration procedure to determine the numberof hammer
47、drops in the field.8.4 The total number of drops is compared with the targetnumber of drops at the same water content to establish thepass/fail compaction criteria. The pass criterion is establishedwhen the number of drops exceeds the target number of dropsobtained from calibration.8.5 It is recomme
48、nded to use the device at least three timesat each test section and take the average drop count. Thereadings should be taken at a minimum distance of 6 in. (150mm) from each other. If a soft zone or the presence of a rockcauses one of the readings to be significantly different than theother readings
49、 in the layer, this reading should not be includedin the averaging and it should be repeated in another location.NOTE 4It is recommended to take more than three readings whentesting materials with high variability such as soils containing gravel andgravel type soil.FIG. 3 Schematic of the 5-lb DCP with Extension Rod in ConfinedExcavationFIG. 4 Detail of the Sleeve Used with Extension RodD7380 1548.6 Testing a layer in a narrow trench below gradeAnextension rod is added to the driving rod when the device isused to monitor compaction in deep trenches. The slee
