1、Designation: D6635 15Standard Test Method forPerforming the Flat Plate Dilatometer1This standard is issued under the fixed designation D6635; 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 pa
2、rentheses 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 describes an in-situ penetration plusexpansion test. The test is initiated by forcing the steel, flatplate, dilatometer blade2, w
3、ith its sharp cutting edge, into asoil. Each test consists of an increment of penetration, gener-ally vertical, followed by the expansion of a flat, circular,metallic membrane into the surrounding soil. The test providesinformation about the soils in-situ stratigraphy, stress,strength, compressibili
4、ty, and pore-water pressure for use in thedesign of earthworks and foundations.1.2 This method includes specific requirements for thepreliminary reduction of dilatometer test data. It does notspecify how to assess or use soil properties for engineeringdesign.1.3 This method applies best to those san
5、ds, silts, clays, andorganic soils that can be readily penetrated with the dilatometerblade, preferably using static push (see 4.2). Test results forsoils containing primarily gravel-sized particles and larger maynot be useful without additional research.1.4 This method is not applicable to soils th
6、at cannot bepenetrated by the dilatometer2blade without causing signifi-cant damage to the blade or its membrane.1.5 The text of this standard references notes and footnotesthat provide explanatory material. These notes and footnotesshall not be considered as requirements of the standard. Theillustr
7、ations included in this standard are intended only forexplanatory or advisory use1.6 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard. Reporting of test results in units other than SI shallnot be regarded as nonconformance w
8、ith this test method1.7 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.8 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as theindustry standard. In addit
9、ion, they are representative of thesignificant digits that should generally be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users objectives; and it is common practice toincrease or reduce si
10、gnificant digits of reported data to com-mensurate with these considerations. It is beyond the scope ofthis standard to consider significant digits used in analysismethods for engineering design.1.9 ASTM International takes no position respecting thevalidity of any patent rights asserted in connecti
11、on with anyitem mentioned in this standard. Users of this standard areexpressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, areentirely their own responsibility.1.10 This standard does not purport to address all of thesafety conce
12、rns, 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.2. Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil, Rock,
13、 and ContainedFluidsD1586 Test Method for Penetration Test (SPT) and Split-Barrel Sampling of SoilsD2435 Test Methods for One-Dimensional ConsolidationProperties of Soils Using Incremental LoadingD3441 Test Method for Mechanical Cone Penetration Testsof Soil (Withdrawn 2014)41This test method is und
14、er the jurisdiction ofASTM 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, 2015. Published December 2015. Originallyapproved in 2001. Last previous edition approved in 200
15、7 as D6635 01(2007).DOI: 10.1520/D6635-15.2The dilatometer is covered by a patent. Interested parties are invited to submitinformation regarding the identification of an acceptable alternative(s) to thispatented item to the ASTM International Headquarters. Your comments will receivecareful considera
16、tion at a meeting of the responsible technical committee, whichyou may attend.3For 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 Document Summary page on
17、the ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D3740 Practice for M
18、inimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD5778 Test Method for Electronic Friction Cone and Piezo-cone Penetration Testing of SoilsD6026 Practice for Using Significant Digits in GeotechnicalData3. Terminology3.
19、1 Definitions:3.1.1 For definitions of common technical terms in thisstandard, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 A-pressurethe gauge gas pressure against the insideof the membrane when the center of the membrane has liftedabove its support and moved l
20、aterally 0.05-mm (tolerance+0.02, -0.00 mm) into the soil surrounding the blade.3.2.2 B-pressurethe gauge gas pressure against the insideof the membrane when the center of the membrane has liftedabove its support and moved laterally 1.10-mm (60.03 mm)into the soil surrounding the blade.3.2.3 C-press
21、ureThe gauge gas pressure against the insideof the membrane when the center of the membrane returns tothe A-pressure position during a controlled, gradual deflationfollowing the B-pressure.3.2.4 dilatometer soundingthe entire sequence of dilatom-eter tests along a vertical line of penetration in the
22、 soil.3.2.5 dilatometer test (DMT)the complete procedure ofpenetration, membrane inflation and then deflation for a singletest depth using the flat plate dilatometer.3.2.6 membranea thin, flexible, 60-mm diameter circularpiece of sheet metal (usually stainless steel), fixed around itsedges, that mou
23、nts on one side of the dilatometer blade andwhich, as a result of an applied internal gas pressure, expandsinto the soil in an approximate spherical shape along an axisperpendicular to the plane of the blade.3.3 Symbols:3.3.1 Athe gauge gas pressure inside the membrane(corrected for Zm) required to
24、overcome the stiffness of themembrane and move it inward to a center-expansion of 0.05mm (a negative gauge or suction pressure, but recorded aspositive) with only ambient atmospheric pressure acting exter-nally.3.3.2 Bthe gauge gas pressure inside the membrane(corrected for Zm) required to overcome
25、the stiffness of themembrane and move it outward to a center-expansion of 1.10mm against only the ambient atmospheric pressure.3.3.3 EDthe dilatometer modulus, based on linear elastictheory, and the primary index used in the correlation for theconstrained and Youngs moduli (see Section 10).3.3.4 Gmb
26、ulk specific gravity = moist soil unit weightdivided by the unit weight of water.3.3.5 IDthe dimensionless dilatometer material index,used to identify soil type and delineate stratigraphy (seeSection 10).3.3.6 KDthe dimensionless dilatometer horizontal stressindex, the primary index used in the corr
27、elation for in-situhorizontal stress, overconsolidation ratio, and undrained shearstrength in cohesive soils. KDis similar to the at-rest coefficientof earth pressure except that it includes blade penetrationeffects.3.3.7 Pthe total push, or thrust force required to advanceonly the dilatometer blade
28、 to its test depth, measured at its testdepth and exclusive of soil or other friction along the pushrods.3.3.8 p0the A-pressure reading, corrected for Zm, the Amembrane stiffness at 0.05-mm expansion, and the 0.05-mmexpansion itself, to estimate the total soil stress acting normalto the membrane imm
29、ediately before its expansion into the soil(0.00-mm expansion, see Section 10).3.3.9 p1the B-pressure reading corrected for Zmand theB membrane stiffness at 1.10-mm expansion to give the totalsoil stress acting normal to the membrane at 1.10-mm mem-brane expansion (see Section 10).3.3.10 p2The C-pre
30、ssure reading corrected for Zmand theA membrane stiffness at 0.05-mm expansion and used toestimate pore-water pressure (see 10.3).3.3.11 vvertical effective stress at the center of themembrane before the insertion of the DMT blade.3.3.12 vtotal vertical stress at the center of the membranebefore the
31、 insertion of the DMT blade, generally calculatedfrom unit weights estimated using the DMT results.3.3.13 u0the pore-water pressure acting at the center ofthe membrane before the insertion of the DMT blade (oftenassumed as hydrostatic below the water table surface).3.3.14 Zmthe gauge pressure deviat
32、ion from zero whenvented to atmospheric pressure (an offset used to correctpressure readings to the true gauge pressure).4. Summary of Test Method4.1 A dilatometer test (DMT) consists of forcing thedilatometer blade into the soil, with the membrane facing thehorizontal direction, to a desired test p
33、enetration, measuringthe thrust to accomplish this penetration and then using gaspressure to expand a circular steel membrane located on oneside of the blade. The operator measures and records thepressure required to produce expansion of the membrane intothe soil at two preset deflections. The opera
34、tor then deflates themembrane, possibly recording an optional third measurement,advances the blade the desired penetration increment andrepeats the test. Each test sequence typically requires about twominutes.Adilatometer sounding consists of the results from allthe tests at one location presented i
35、n a fashion indicatingvariation with depth.4.2 The operator may advance the blade using either aquasi-static push force or dynamic impact from a hammer, withquasi-static push preferred. A record of the penetration resis-tance (thrust force or blows per penetration increment) isdesirable both for con
36、trol of the penetration and later analyses.NOTE 1In soils sensitive to impact and vibrations, such as medium toloose sands or sensitive clays, dynamic insertion methods can significantlychange the test results compared to those obtained using a quasi-staticD6635 152push. In general, structurally sen
37、sitive soils will appear more compressiblewhen tested using dynamic insertion methods. In such cases check fordynamic effects and, if important, calibrate and adjust test interpretationsaccordingly.4.3 The penetration increment typically used in a DMTsounding varies from 0.15 to 0.30 m. Most soundin
38、gs areperformed vertically and this Test Method requires that themembrane face the horizontal direction. Testing below impen-etrable layers will require preboring and supporting (if re-quired) a borehole with a diameter of at least 100 mm.4.4 The operator performs a membrane calibration beforeand af
39、ter each DMT sounding.4.5 The field data is then interpreted to obtain profiles ofthose engineering soil properties of interest over the depthrange of the DMT sounding.5. Significance and Use5.1 Soundings performed using this test method provide adetailed record of dilatometer results, which are use
40、ful forevaluation of site stratigraphy, homogeneity, depth to firmlayers, voids or cavities, and other discontinuities. The pen-etration resistance, if obtained, and subsequent membraneexpansion are used for soil classification and correlation withthe engineering properties of soils.5.2 The DMT may
41、provide measurements of penetrationresistance, lateral stress, deformation modulus, and pore-waterpressure (in sands). However, the in-situ soil properties areaffected by the penetration of the blade. Therefore, publishedcorrelations are used to estimate soil properties for the designand constructio
42、n of earthworks and foundations for structures,and to predict the behavior of soils subjected to static ordynamic loads.5.3 This test method tests the soil in-situ and soil samplesare not obtained. However, the interpretation of the resultsfrom this test method does provide an estimate of the types
43、ofsoil penetrated. Soil samples from parallel borings may beobtained for correlation purposes, but prior information orexperience may preclude the need for borings.NOTE 2The quality of the result produced by this test method isdependent on the competence of the personnel performing it, and thesuitab
44、ility 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 this test methodare cautioned that compliance with Practice D3740 does not in itselfassure reliable resul
45、ts. Reliable results depend on many factors; PracticeD3740 provides a means of evaluating some of those factors.6. Apparatus6.1 The annotated Fig. 1 illustrates the major components ofthe DMT equipment, exclusive of that required to insert theblade. The equipment dimensions, tolerances, deflections,
46、 etc.affect the test results and shall conform to the values providedherein.6.1.1 Blade, (1), 96 mm wide (95 to 97 mm) and 15 mmthick (13.8 to 15 mm).6.1.2 Membrane, (2), 60 mm diameter.6.1.3 Control Unit, with a pressure readout system (3) thatcan vary in type, range, and sensitivity as required. T
47、hepressure readout system shall have an accuracy of 0.5 percentof span or better (0.25 percent of span is recommended). Theunit shown has both low-range and high-range Bourdon gaugesthat are read manually. Older units have a single Bourdongauge, typically medium-range. The gauges should be annuallyc
48、alibrated against a traceable standard, more often if heavilyused. The control unit also includes connections (5) for apressure source, a pneumatic-electrical cable, and an electricalground cable, and has valves to control gas flow and vent thesystem (6).6.1.4 Calibration Syringe, (4) for determinin
49、g the A andB membrane calibrations using the low-range Bourdongauge. Some control units have a separate low-range pressureFIG. 1 DMT EquipmentD6635 153gauge that attaches to the control unit for determining the Aand B membrane calibrations6.1.5 Pneumatic-Electrical Cable, (7) to transmit gas pres-sure and electrical continuity from the control unit to the blade.6.1.6 Ground Cable, (8) to provide electrical continuitybetween the push rod system and the calibration unit.6.2 Insertion equipment is required to advance the blade tothe test depth. T
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