1、Designation: D4186 06 D4186/D4186M 12Standard Test Method forOne-Dimensional Consolidation Properties of SaturatedCohesive Soils Using Controlled-Strain Loading1This standard is issued under the fixed designation D4186;D4186/D4186M; the number immediately following the designation indicatesthe year
2、of original adoption 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. Scope*1.1 This test method is for the determination of the magnit
3、ude and rate-of-consolidation of saturated cohesive soils usingcontinuous controlled-strain axial compression. The specimen is restrained laterally and drained axially to one surface. The axialforce and base excess pressure are measured during the deformation process. Controlled strain compression i
4、s typically referredto as constant rate-of-strain (CRS) testing.1.2 This test method provides for the calculation of total and effective axial stresses, and axial strain from the measurement ofaxial force, axial deformation, chamber pressure, and base excess pressure. The effective stress is compute
5、d using steady stateequations.1.3 This test method provides for the calculation of the coefficient of consolidation and the hydraulic conductivity throughoutthe loading process. These values are also based on steady state equations.1.4 This test method makes use of steady state equations resulting f
6、rom a theory formulated under particular assumptions.Section 5.45.5 presents these assumptions.1.5 The behavior of cohesive soils is strain rate dependent and hence the results of a CRS test are sensitive to the imposed rateof strain. This test method imposes limits on the strain rate to provide com
7、parable results to the incremental consolidation test.test(Test Method D2435).1.6 The determination of the rate and magnitude of consolidation of soil when it is subjected to incremental loading is coveredby Test Method D2435.1.7 This test method applies to intact (Group C and Group D of Practice D4
8、220), remolded, or laboratory reconstituted samplesor specimens.samples.1.8 This test method is most often used for materials of relatively low hydraulic conductivity that generate measurable excessbase pressures. It may be used to measure the compression behavior of essentially free draining soils
9、but will not provide a measureof the hydraulic conductivity or coefficient of consolidation.1.9 All recorded and calculated values shall conform to the guide for significant digits and rounding established in PracticeD6026., unless superseded by this test method. The significant digits specified thr
10、oughout this standard are based on the assumptionthat data will be collected over an axial stress range from 1% of the maximum stress to the maximum stress value.1.9.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industrystandard.
11、 In addition, they are representative of the significant digits that should generally be retained. The procedures used do notconsider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the users objectives;and it is common practice to increase or r
12、educe significant digits of reported data to be commensurate with these considerations.It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.1.9.2 Measurements made to more significant digits or better sensitivity than specified in thi
13、s standard shall not be regarded anon-conformance with this standard.1.10 UnitsThis standard is written using SI units. Inch-pound units are provided for convenience. The values stated in eitherSI units or inch-pound units given in brackets are to be regarded separately as standard. The values state
14、d in inch-pound unitseachsystem may not be exact equivalents; therefore, they each system shall be used independently of the SI system. other. Combiningvalues from the two systems may result in non-conformance with the this standard.1 This test method is under the jurisdiction of ASTM Committee D18
15、on Soil and Rock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved Sept. 1, 2006Nov. 1, 2012. Published December 2006December 2012. Originally approved in 1982. Last previous edition approved in 19982006as D4186 89 (1998)D4186 06
16、. 1. DOI: 10.1520/D4186-06.10.1520/D4186_D4186M-12.This document is not an ASTM standard and is intended only 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 accur
17、ately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor
18、Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.10.1 The gravitational system of inch-pound units is used when dealingworking with inch-pound units. In this system, thepound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The rationalized slug unit
19、is not given, unlessdynamic (F = ma) calculations are involved.1.10.2 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit ofmass (lbm) and of force (lbf). This implicitly combines two separate systems of units; that is, the absolute sy
20、stem and thegravitational system. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a singlestandard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit formass. However, the use of b
21、alances or scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regardedas non-conformance with this standard.1.11 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address allof the safety concerns, if any, asso
22、ciated with its use. It is the responsibility of the user of this standard to establish appropriatesafety and health practices and determine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained Flui
23、dsD854 Test Methods for Specific Gravity of Soil Solids by Water PycnometerD1587 Practice for Thin-Walled Tube Sampling of Soils for Geotechnical PurposesD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2435 Test Methods for One-Dimensional Consoli
24、dation Properties of Soils Using Incremental LoadingD2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)D2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)D3213 Practices for Handling, Storing, and Preparing Soft In
25、tact Marine SoilD3550 Practice for Thick Wall, Ring-Lined, Split Barrel, Drive Sampling of SoilsD3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4220 Practices for Preserving and Transporting Soil
26、 SamplesD4318 Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of SoilsD4452 Practice for X-Ray Radiography of Soil SamplesD4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and ConstructionMaterials TestingD5720 Practice for S
27、tatic Calibration of Electronic Transducer-Based Pressure Measurement Systems for Geotechnical PurposesD6026 Practice for Using Significant Digits in Geotechnical DataD6027 Practice for Calibrating Linear Displacement Transducers for Geotechnical PurposesD6519 Practice for Sampling of Soil Using the
28、 Hydraulically Operated Stationary Piston SamplerD6913 Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve AnalysisD7015 Practices for Obtaining Intact Block (Cubical and Cylindrical) Samples of Soils3. Terminology3.1 Definitions:3.1.1 For definitions of othertechnical terms
29、 used in this Test Method, see Terminology D653.3.2 Definitions of Terms:3.2.1 back pressure, (ub (FL -2)a fluid pressure in excess of atmospheric pressure that is applied to the drainage boundary ofa test specimen.3.2.1.1 DiscussionTypically, the back pressure is applied to cause air in the pore sp
30、aces to pass into solution, thus saturating the specimen.3.2.2 consolidometeran apparatus containing a specimen under conditions of nonegligible lateral deformation while allowingone-dimensional axial deformation and one directional axial flow.3.2.3 excess pore-water pressure, u (FL-2)in effective s
31、tress testing, the pressure that exists in the pore fluid relative to (aboveor below) the back pressure.3.2.4 total axial stress, a (FL-2)in effective stress testing, the totalnormal stress applied to the free draining surface axialboundary of the specimen in excess of the back pressure.2 For refere
32、nced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D4186/D4186M 1223.3 Definitions of Terms Specific to This Standard:3.3
33、.1 axial displacement reading, AD (volts) readings taken during the test of the axial displacement transducer.3.3.2 axial force reading, AF (volts)readings taken during the test of the axial force transducer.3.3.1 average effective axial stress, a (FL-2)the effective stress calculated using either t
34、he linear or nonlinear theoryequations to represent the average value during at any time under steady state constant strain rate conditions.3.3.2 axial deformation reading, AD (volts) readings taken during the test of the axial deformation transducer.3.3.3 axial force reading, AF (volts)readings tak
35、en during the test of the axial force transducer.3.3.4 base excess pressure, um (FL-2)the fluid pressure in excess (above or below) of the back pressure that is measured atthe impervioussealed boundary of the specimen under conditions of one way drainage. The base excess pressure will be positivedur
36、ing loading and negative during unloading.3.3.5 base excess pressure ratio, Ru (D) the ratio of (1) the base excess pressure to (2) the total axial stress. This value willbe positive during loading and negative during unloading.3.3.6 base excess pressure reading, BEP (volts)readings taken during the
37、 test of the base excess pressure transducer whenusing a differential pressure transducer which is referenced to the chamber pressure.3.3.7 base pressure, um (FL-2 )the fluid pressure measured at the impervioussealed boundary (usually at the base of theconsolidometer) of the specimen under condition
38、s of one way drainage.3.3.8 base pressure reading, BP (volts)readings taken during the test of the base pressure transducer.3.3.9 chamber pressure, c (FL-2)the fluid pressure inside the consolidometer. In most CRS consolidometers, the chamberfluid is in direct contact with the specimen. For these de
39、vices (and this test method), the chamber pressure will be equal to the backpressure.3.3.10 chamber pressure reading, CP (volts)readings taken during the test of the chamber pressure transducer.3.3.11 constant rate-of-strain, CRSa method of consolidating a specimen in which the surface is deformed a
40、t a uniform ratewhile measuring the axial deformation, axial reaction force, and induced base excess pressure.3.3.12 dissipationchange over time of an excess initial condition to a time independent condition.3.3.13 equilibrated waterpotabletest water that has come to equilibrium with the current roo
41、m conditions includingtemperature, chemistry, dissolved air, and stress state.3.3.14 linear theory (calculation method)a set of equations derived based on the assumption that the coefficient of volumecompressibility (mv) is constant.constant (the soil follows a linear strain versus effective stress
42、relationship).3.3.15 monofilament nylon screenthin porous synthetic woven filter fabric made of single untwisted filament nylon.3.3.16 nonlinear theory (calculation method) a set of equations derived based on the assumption that the compression index(Cc) is constant.constant (the soil follows a line
43、ar strain versus log effective stress relationship).3.3.17 steady state conditionin CRS testing , a time independent strain distribution within the specimen that changes inaverage value as loading proceeds.3.3.18 pore-water pressuresteady state factor, F (D)a dimensionless number equal to the change
44、 in total axial stress minusthe base excess pressure divided by the change in total axial stress.3.3.16 pore-water pressure ratio, Ru (D) the base excess pressure divided by the total axial stress.3.3.17 steady state conditionin CRS testing , a time independent strain distribution within the specime
45、n that changes inaverage value as loading proceeds.3.3.19 transient conditionin CRS testing, a time dependent variation in the strain distribution within the specimen that iscreated at the start of a CRS loading or unloading phase or when the strain rate changes and then decays with time to a steady
46、 statestrain distribution.3.3.20 unit conversion factora constant used in an equation to unify the system of units (eg, SI to inch pound) or prefix ofvariables (eg. cm to m) within the same system of units.4. Summary of Test Method4.1 In this test method the specimen is constrained axially between t
47、wo parallel, rigid platensboundaries and laterally such thatthe cross sectional area remains essentially constant. Drainage is provided along one boundary (typically the top) and the fluidpressure is measured at the other sealed boundary (typically the base).base) of the consolidometer.4.2 A back pr
48、essure is applied to saturate both the specimen and the base pressure measurement system.4.3 The specimen is deformed axially at a constant rate while measuring the time, axial deformation, reaction force, chamberpressure, and base pressure. A standard test includes one loading phase, one constant l
49、oad phase, and one unloading phase. TheD4186/D4186M 123constant load phase allows the base excess pressure to return to near zero prior to unloading. More extensive tests can be performedby including more phases to obtain unload-reload cycle(s).4.4 The rate of deformation is selected to produce a pore base excess pressure ratio that is between 3 % and 15 % about 3 %and 15 % at the end of the loading phase.NOTE 1The base excess pressure ratio typically decreases during loading. The lower limit provides sufficient pressure to compute th
