1、Designation: D 5778 95 (Reapproved 2000)Standard Test Method forPerforming Electronic Friction Cone and PiezoconePenetration Testing of Soils1This standard is issued under the fixed designation D 5778; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 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 test method covers the procedure for determiningthe resistance to penetration of
3、a conical pointed penetrometeras it is advanced into subsurface soils at a slow, steady rate.1.2 This test method is also used to determine the frictionalresistance of a cylindrical sleeve located behind the conicalpoint as it is advanced through subsurface soils at a slow,steady rate.1.3 This test
4、method applies to friction-cone penetrometersof the electronic type.1.4 This test method can be used to determine pore pressuredevelopment during push of a piezocone penetrometer. Porepressure dissipation, after a push, can also be monitored forcorrelation to soil compressibility and permeability.1.
5、5 Other sensors such as inclinometer, seismic, and tem-perature sensors may be included in the penetrometer toprovide useful information. The use of an inclinometer ishighly recommended since it will provide information onpotentially damaging situations during the sounding process.1.6 Cone penetrati
6、on test data can be used to interpretsubsurface stratigraphy, and through use of site specific corre-lations it can provide data on engineering properties of soilsintended for use in design and construction of earthworks andfoundations for structures.1.7 The values stated in SI units are to be regar
7、ded asstandard. Within Section 13 on Calculations, SI metric units areconsidered the standard. Other commonly used units such asthe inch-pound system are shown in brackets. The various datareported should be displayed in mutually compatible units asagreed to by the client or user. Cone tip projected
8、 area iscommonly referred to in centimetres for convenience. Thevalues stated in each system are not equivalents; therefore,each system must be used independently of the other.NOTE 1This test method does not include hydraulic or pneumaticpenetrometers. However, many of the procedural requirements he
9、reincould apply to those penetrometers.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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory l
10、imitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 653 Terminology Relating to Soil, Rock, and ContainedFluids2E 4 Practice for Force Verification of Testing Machines33. Terminology3.1 Definitions:3.1.1 Definitions are in accordance with TerminologyD 653.3.2 Definitions of Terms Spe
11、cific to This Standard:3.2.1 apparent load transferapparent resistance measuredon either the cone or friction sleeve of an electronic conepenetrometer while that element is in a no-load condition butthe other element is loaded. Apparent load transfer is the sumof cross talk, subtraction error, and m
12、echanical load transfer.3.2.2 baselinea set of zero load readings, expressed interms of apparent resistance, that are used as reference valuesduring performance of testing and calibration.3.2.3 conethe conical point of a cone penetrometer onwhich the end bearing component of penetration resistance i
13、sdeveloped. The cone has a 60 apex angle, a projected(horizontal plane) surface area or cone base area of 10 or 15cm2, and a cylindrical extension behind the cone base.3.2.4 cone penetration testa series of penetration readingsperformed at one location over the entire depth when using acone penetrom
14、eter. Also referred to as cone sounding.3.2.5 cone penetrometera penetrometer in which the lead-ing end of the penetrometer tip is a conical point designed forpenetrating soil and for measuring the end-bearing componentof penetration resistance.3.2.6 cone resistance, qcthe end-bearing component ofpe
15、netration resistance. The resistance to penetration developedon the cone is equal to the vertical force applied to the conedivided by the cone base area.3.2.7 corrected total cone resistance, qttip resistance1This test method is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the
16、 direct responsibility of Subcommittee D18.02 on Sampling andRelated Field Testing for Soil Evaluations.Current edition approved Sept. 10, 1995. Published January 1996.2Annual Book of ASTM Standards, Vol 04.08.3Annual Book of ASTM Standards, Vol 03.01.1Copyright ASTM, 100 Barr Harbor Drive, West Con
17、shohocken, PA 19428-2959, United States.corrected for water pressure acting behind the tip (see 13.2.1).Correction for water pressure requires measuring water pres-sures with a piezocone element behind the tip at location u2.The correction results in estimated total tip resistance.3.2.8 cross talkan
18、 apparent load transfer between the coneand the friction sleeve caused by interference between theseparate signal channels.3.2.9 electronic cone penetrometera friction cone pen-etrometer that uses force transducers, such as strain gage loadcells, built into a non-telescoping penetrometer tip for mea
19、sur-ing, within the penetrometer tip, the components of penetrationresistance.3.2.10 electronic piezocone penetrometeran electroniccone penetrometer equipped with a low volume fluid chamber,porous element, and pressure transducer for determination ofpore pressure at the porous element soil interface
20、.3.2.11 end bearing resistancesame as cone resistance ortip resistance, qc.3.2.12 equilibrium pore water pressure, u0at rest waterpressure at depth of interest. Same as hydrostatic pressure (seeTerminology D 653).3.2.13 excess pore water pressure, Duthe difference be-tween pore pressure measured as
21、the penetration occurs, u, andestimated equilibrium pore water pressure (u0 u). Excesspore pressure can either be positive or negative.3.2.14 friction cone penetrometera cone penetrometerwith the capability of measuring the friction component ofpenetration resistance.3.2.15 friction ratio, Rfthe rat
22、io of friction sleeve resis-tance, fs, to cone resistance, qc, measured at where the middleof the friction sleeve and cone point are at the same depth,expressed as a percentage.3.2.16 friction reducera narrow local protuberance on theoutside of the push rod surface, placed at a certain distanceabove
23、 the penetrometer tip, that is provided to reduce the totalside friction on the push rods and allow for greater penetrationdepths for a given push capacity.3.2.17 friction sleevean isolated cylindrical sleeve sectionon a penetrometer tip upon which the friction component ofpenetration resistance dev
24、elops. The friction sleeve has asurface area of either 150 for 10 cm2cone tip.3.2.18 friction sleeve resistance, fs the friction componentof penetration resistance developed on a friction sleeve, equalto the shear force applied to the friction sleeve divided by itssurface area.3.2.19 FSOabbreviation
25、 for full-scale output. The outputof an electronic force transducer when loaded to 100 % ratedcapacity.3.2.20 local side frictionsame as friction sleeve resis-tance.3.2.21 penetration resistance measuring system a mea-suring system that provides the means for transmitting infor-mation from the penet
26、rometer tip and displaying the data at thesurface where it can be seen or recorded.3.2.22 penetrometeran apparatus consisting of a series ofcylindrical push rods with a terminal body (end section), calledthe penetrometer tip, and measuring devices for determinationof the components of penetration re
27、sistance.3.2.23 penetrometer tipthe terminal body (end section) ofthe penetrometer which contains the active elements that sensethe components of penetration resistance. The penetrometer tipmay include additional electronic instrumentation for signalconditioning and amplification.3.2.24 piezoconesam
28、e as electronic piezocone penetrom-eter (see 3.2.10).3.2.25 piezocone pore pressure, ufluid pressure measuredusing the piezocone penetration test.3.2.26 piezocone pore pressure measurement locations, u1,u2,u3fluid pressure measured by the piezocone penetrometerat specific locations on the penetromet
29、er as follows: u1porepressure filter location on the face or tip of the cone, u2porepressure filter location immediately behind the cone tip (stan-dard location) and, u3pore pressure filter location behind thefriction sleeve.3.2.27 pore pressure ratiothe ratio of excess pore pres-sure, Du, to cone r
30、esistance, qc, expressed as a percentage (see13.5.3).3.2.28 pore pressure ratio parameter, Bqthe ratio ofexcess pore pressure at measurement location Du2, to correctedtotal cone resistance qt, minus the total vertical stress, sv(see13.5.4.1).3.2.29 push rodsthe thick-walled tubes or rods used toadva
31、nce the penetrometer tip.3.2.30 sleeve friction, sleeve, and friction resistancesameas friction sleeve resistance.3.2.31 subtraction erroran apparent load transfer fromthe cone to the friction sleeve of a subtraction type electroniccone penetrometer caused by minor voltage differences inresponse to
32、load between the two strain element cells.3.3 Abbreviations:3.3.1 CPTabbreviation for the cone penetration test.3.3.2 CPTuabbreviation for the piezocone penetrationtest.4. Summary of Test Method4.1 A penetrometer tip with a conical point having a 60apex angle and a cone base area of 10 or 15 cm2is a
33、dvancedthrough the soil at a constant rate of 20 mm/s. The force on theconical point (cone) required to penetrate the soil is measuredby electrical methods, at a minimum of every 50 mm ofpenetration. Stress is calculated by dividing the measured force(total cone force) by the cone base area to obtai
34、n coneresistance, qc.4.2 A friction sleeve is present on the penetrometer imme-diately behind the cone tip, and the force exerted on the frictionsleeve is measured by electrical methods at a minimum ofevery 50 mm of penetration. Stress is calculated by dividingthe measured force by the surface area
35、of the friction sleeve todetermine friction sleeve resistance, fs.4.3 Many penetrometers are capable of registering porewater pressure induced during advancement of the penetrom-eter tip using an electronic pressure transducer. These pen-etrometers are called “piezocones.” The piezocone is advanceda
36、t a rate of 20 mm/s, and readings are taken at a minimum ofevery 50 mm of penetration. The dissipation of either positiveor negative excess pore water pressure can be monitored bystopping penetration, unloading the push rod, and recordingD 57782pore pressure as a function of time. When pore pressure
37、becomes constant it is measuring the equilibrium value orpiezometric level at that depth.5. Significance and Use5.1 Tests performed using this test method provide a de-tailed record of cone resistance which is useful for evaluationof site stratigraphy, homogeneity and depth to firm layers,voids or c
38、avities, and other discontinuities. The use of a frictionsleeve and pore pressure element can provide an estimate ofsoil classification, and correlations with engineering propertiesof soils. When properly performed at suitable sites, the testprovides a rapid means for determining subsurface conditio
39、ns.5.2 This test method provides data used for estimatingengineering properties of soil intended to help with the designand construction of earthworks, the foundations for structures,and the behavior of soils under static and dynamic loads.5.3 This test method tests the soil in situ and soil samples
40、are not obtained. The interpretation of the results from this testmethod provides estimates of the types of soil penetrated.Engineers may obtain soil samples from parallel borings forcorrelation purposes but prior information or experience maypreclude the need for borings.6. Interferences6.1 Refusal
41、, deflection, or damage to the penetrometer mayoccur in coarse grained soil deposits with maximum particlesizes that approach or exceed the diameter of the cone.6.2 Partially lithified and lithified deposits may cause re-fusal, deflection, or damage to the penetrometer.6.3 Standard push rods can be
42、damaged or broken underextreme loadings. The amount of force that push rods are ableto sustain is a function of the unrestrained length of the rodsand the weak links in the push rod-penetrometer tip string suchas push rod joints and push rod-penetrometer tip connections.The force at which rods may b
43、reak is a function of theequipment configuration and ground conditions during pen-etration. Excessive rod deflection is the most common causefor rod breakage.7. Apparatus7.1 Friction Cone PenetrometerThe penetrometer tipshould meet requirements as given below and in 10.1. In atypical friction cone p
44、enetrometer tip (as shown on Fig. 1 (1),4the forces produced by friction sleeve resistance and coneresistance during penetration are measured by two load cellswithin the electronic friction cone penetrometer. Either inde-pendent or subtraction-type electronic friction cone penetrom-eter tips are acc
45、eptable for use.7.1.1 In the subtraction-type friction cone penetrometer, thecone and sleeve both produce compressive forces on the loadcells. The load cells are joined together in such a manner thatthe cell nearest the cone (the “C” cell on Fig. 1(b) measuresthe compressive force on the cone while
46、the second cell (the“C + S” cell on Fig. 1( b) measures the sum of the compres-sive forces on both the cone and friction sleeve. The compres-sive force from just the friction sleeve is computed then bysubtraction. This cone design finds the most common use inindustry. It is preferred because of its
47、rugged design. Thisdesign forms the basis for minimum performance requirementsfor electronic penetrometers.7.1.1.1 In the independent tension-type cone penetrometertip, the cone produces a compression force on the cone loadcell (the “C” cell on Fig. 1(a) while the friction sleeveproduces a tensile f
48、orce on the independent friction sleeve loadcell (the “S” cell on Fig. 1(a). Designs are also availablewhere the independent sleeve element is placed in compres-sion. This penetrometer tip design results in a higher degree ofaccuracy in friction sleeve measurement, but, depending on thedesign, it is
49、 more susceptible to damage under extreme loadingconditions.7.1.1.2 Typical general purpose cone penetrometers aremanufactured to full scale outputs equivalent to net loads of 10to 20 tons. Often, weak soils are the most critical in aninvestigation program and in some cases very accurate frictionsleeve data may be required. To gain better resolution, the FSOcan be lowered or independent type penetrometers can beselected. A low FSO subtraction cone may provide moreaccurate data than a standard FSO independent type conedepending on such factors a
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