1、Designation: D5855/D5855M 15Standard Test Method for(Analytical Procedure) for Determining Transmissivity andStorage Coefficient of Confined Nonleaky or Leaky Aquiferby Constant Drawdown Method in Flowing Well1This standard is issued under the fixed designation D5855/D5855M; the number immediately f
2、ollowing the designation indicates theyear 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 me
3、thod covers an analytical solution fordetermining transmissivity and storage coefficient of a leaky ornonleaky confined aquifer. It is used to analyze data on the flowrate from a control well while a constant head is maintained inthe well.1.2 This analytical procedure is used in conjunction with the
4、field procedure in Practice D5786.1.3 LimitationsThe limitations of this technique for thedetermination of hydraulic properties of aquifers are primarilyrelated to the correspondence between field situation and thesimplifying assumption of the solution.1.4 UnitsThe values stated in either SI units o
5、r inch-pound units are to be regarded separately as standard. Thevalues in each system may not be exact equivalents; thereforeeach system shall be used independently of the other. Combin-ing values from the two systems may result in non-conformance with the standard. Reporting of test results inunit
6、s other than SI shall not be regarded as nonconformancewith this test method.1.5 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6 This standard does not purport to address all of thesafety concerns, if any, associa
7、ted 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 ContainedFluids
8、D3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4043 Guide for Selection of Aquifer Test Method inDetermining Hydraulic Properties by Well TechniquesD5786 Practice for (Field Procedure) for Consta
9、nt Draw-down Tests in Flowing Wells for Determining HydraulicProperties of Aquifer SystemsD6026 Practice for Using Significant Digits in GeotechnicalData3. Terminology3.1 Derfinitions:3.1.1 For definitions of terms used in this test method, seeTerminology D653.3.2 Symbols and Dimensions:3.2.1 Ttrans
10、missivity L2T1.3.2.2 K1 modified Bessel function of the second kind, firstorder nd.3.2.3 K2 modified Bessel function of the second kind,zero order nd.3.2.4 J0 Bessel function of the first kind, zero order nd.3.2.5 Y0 Bessel function of the second kind, zero ordernd.3.2.6 W(u)w (well) function of u n
11、d.3.2.7 uvariable of integration nd.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved Nov. 1, 2015. Published December 2015. Originallyapproved
12、 in 1995. Last previous edition approved in 2013 as D5855 95 (2013).DOI: 10.1520/D5855_D5855M-15.2For 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 Docum
13、ent Summary page onthe ASTM website.*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 States13.2.8 telapsed time test T.3.2.9 Qdischarge rate L3T1.3.2.10 sWconstant drawdown in c
14、ontrol well L.3.2.11 Sstorage coefficient nd.3.2.12 rWradius of control well.4. Summary of Test Method4.1 This test method describes the analytical procedure foranalyzing data collected during a constant drawdown aquifertest. This test method is usually performed on a flowing well.After the well has
15、 been shut-in for a period of time, the well isopened and the discharge rate is measured over a period of timeafter allowing the well to flow. The water level in the controlwell while the well is flowing is the elevation of the opening ofthe control well through which the water is allowed to flow.Da
16、ta are analyzed by plotting the discharge rate versus time.NOTE 1This test method involves the withdrawal of water from acontrol well that is fully screened through the confined aquifer. Thewithdrawal rate is varied to cause the water level within the well to remainconstant. The field procedure invo
17、lved in conducting a constant drawdowntest is given in Practice D5786. Methods used to develop a conceptualmodel of the site and for initially selecting an analytical procedure aredescribed in Guide D4043.4.2 Leaky Aquifer SolutionThe solution is given by Han-tush.3Transmissivity is calculated as fo
18、llows:NOTE 2These are Eq (93) through (97) of Lohman.4T 5Q2sWG,rW/B!L2T21# (1)where: 5TtSrW2nd# (2)rW/B 5 rWT/K/b!#20.5L2# (3)and:GFrWBG5FrWBGFK1rw/b!K0rW/b!G1r2expF2SrWBD2G. (4)* uexp2u2!J02u!1Y02u!duu21rW/B!2nd#4.2.1 Storage coefficient is given by:S 5TtrW2nd# (5)4.3 Non-Leaky Aquifer:4.3.1 Log-Lo
19、gThe solution is given by Lohman.4NOTE 3These equations are Eq (66) through (69) of Lohman.44.3.1.1 Transmissivity is calculated as follows:T 5Q2G!sWL2T21# (6)where: 5TtSrW2nd# (7)and:Ga! 54*xe2x2F21 tan21SYox!Jox!DGdx nd# (8)4.3.1.2 Storage coefficient is given by:S 5TtrW2nd# (9)4.3.2 Semi-LogThe s
20、olution is given by Jacob andLohman.5NOTE 4Jacob and Lohman5showed that for all but extremely smallvalues of t, the function of G(a) shown above can be approximated veryclosely by 2/ W(u). For sufficiently small values of u, W(u) are furtherapproximated by 2.30 log102.25Tt/rW2S. The use of this semi
21、-logarithmicmethod will produce values of transmissivity that are slightly elevated.Examples of this error are shown below:u W(u)EstimatedError, %0.25000 1.044283 250.00625 4.504198 100.000833 6.513694 51.25E-05 10.71258 24.3.2.1 Transmissivity is calculated as follows:NOTE 5These equations are Eqs
22、(71) and (73) of Lohman.4T 52.304sW/Q!/log10t/rW2!L2T21# (10)by extrapolating the straight line to sW/Q = 0 (the point ofzero drawdown), storage coefficient is given by:S 5 2.25 TtrW2nd# (11)NOTE 6In (Eq 10) and (Eq 11), Q is in cubic feet per day, t is in days.5. Significance and UseNOTE 7The quali
23、ty of the result produced by this standard 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/et
24、c. Users of this 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 those factors.5.1 AssumptionsLeaky Aquifer:5.1.1 Drawdown (sW) in the control well is co
25、nstant,5.1.2 Well is infinitesimal diameter and fully penetratesaquifer,5.1.3 The aquifer is homogeneous, isotropic, and areallyextensive, and5.1.4 The control well is 100 % efficient.5.2 AssumptionsNonleaky Aquifer:5.2.1 Drawdown (sW) in the control well is constant,5.2.2 Well is infinitesimal diam
26、eter and fully penetratesaquifer,3Hantush, M. S., “Nonsteady Flow to Flowing Wells in LeakyAquifer,” Journalof Geophysical Research, Vol 64, No. 8, 1959, pp. 10431052.4Lohman, S. W., “Ground-Water Hydraulics,” Professional Paper 708, U.S.Geological Survey, 1972.5Jacob, C. E., and Lohman, S. W., “Non
27、steady Flow to a Well of ConstantDrawdown in an Extensive Aquifer,” American Geophysical Union Transactions,Vol 33, No. 4, 1952, pp. 552569.D5855/D5855M 1525.2.3 The aquifer is homogeneous, isotropic, and areallyextensive,5.2.4 Discharge from the well is derived exclusively fromstorage in the nonlea
28、ky aquifer, and5.2.5 The control well is 100 % efficient.5.3 Implications of Assumptions:5.3.1 The assumptions are applicable to confined aquifersand fully penetrating control wells. However, this test methodmay be applied to partially penetrating wells where the methodmay provide an estimate of hyd
29、raulic conductivity for theaquifer adjacent to the open interval of the well if thehorizontal hydraulic conductivity is significantly greater thanthe vertical hydraulic conductivity.5.3.2 Values obtained for storage coefficient are less reliablethan the values calculated for transmissivity. Storage
30、coeffi-cient values calculated from control well data are not reliable.6. Apparatus6.1 Analysis of data from the field procedure (see PracticeD5786) by the methods specified in this procedure requires thatthe control well and observation wells meet the specificationsgiven in the apparatus section of
31、 Practice D5786.7. Procedure7.1 Data CollectionProcedures to collect the field dataused by the analytical procedures described in this test methodare given in Practice D5786.7.2 Data Calculation and InterpretationPerform the pro-cedures for calculation and interpretation of test data as givenin Sect
32、ion 8.7.3 ReportPrepare a report as given in Section 9.8. Calculation and Interpretation of Results8.1 Leaky Aquifer Solution:8.1.1 (Eq 4) cannot be integrated directly but has beenevaluated numerically and the values are given in Table 1 ofHantush.38.1.2 ProcedureThe graphical procedure is based on
33、 thefunctional relations between G(,rW/B) and .8.1.2.1 Plot values of G(,rW/B) versus at a logarithmicscale. This plot is referred to as the type curve plot.An exampleof this type curve is given in Fig. 1. This plot is after Plate 5 ofLohman.48.1.2.2 On logarithmic tracing paper of the same scale as
34、 thetype curve plot values of Q on the vertical coordinate againstt on the horizontal coordinate.8.1.2.3 Overlay the data plot on the type curve plot and,while the coordinate axes of the two plots are held parallel,shift the data plot to align with the type curve.8.1.2.4 Select and record the values
35、 of an arbitrary point,referred to as the match point, anywhere on the overlappingpart of the plots. Record the values of G(,rWB), , Q, and t.For convenience the point may be selected where G(,rWB)and are integer values.8.1.2.5 Using the coordinates of the match point, determinethe transmissivity an
36、d storage coefficient from (Eq 1) and (Eq5).8.2 Non-Leaky Aquifer SolutionLog-Log Solution:8.2.1 (Eq 8) cannot be integrated directly but has beenevaluated numerically and the values are given in Table 7 ofLohman.48.2.2 ProcedureThe graphical procedure is based on rela-tionships of Q/sWand t/rW2.8.2
37、.2.1 Plot values G() versus at a logarithmic scale. Thisplot is referred to as the type curve plot. An example of thistype curve is given in Fig. 2, that is after Plate 1 of Lohman.48.2.2.2 On logarithmic tracing paper of the same scale as thetype curve, plot values of Q/sWversus t/rW2. Alternativel
38、y, plotvalues of Q versus t.NOTE 1After Lohman,4Plate 5.FIG. 1 Logarithmic Plot of Versus G(, rW/B )D5855/D5855M 1538.2.2.3 Overlay the data plot on the type curve plot and,while the coordinate axes of the two plots are held parallel,shift the data plot to align with the type curve.8.2.2.4 Select an
39、d record the values of an arbitrary point,referred to as the match point, anywhere on the overlappingpart of the plots. Record values of G(), , Q/sWand t/rW2,oralternatively G(), ,Qand t.8.2.2.5 Using the coordinates of the match point, determinethe transmissivity and storage coefficient from (Eq 8)
40、 and (Eq9).8.3 Non-Leaky Aquifer SolutionSemi-Log Solution:8.3.1 ProcedureThe graphical procedure is based on therelationships between sWQ and t/rW2.8.3.1.1 Plot values of sWQ versus t/rW2on a semilogarith-mic scale. An example of this plot is given in Fig. 3, that isafter Fig. 17 of Lohman.4The tab
41、ulated data used for this plotare shown in Table 1, that is after Table 8 of Lohman.48.3.1.2 From this semilogarithmic plot, determine sWQ,(sWQ) and t/rW2.8.3.1.3 Substitute these values into (Eq 10) and (Eq 11)todetermine the transmissivity and storage coefficient.9. Records9.1 Report the following
42、 information:9.1.1 IntroductionThe introductory section is intended topresent the scope and purpose of the constant drawdownmethod for determining transmissivity and storage coefficientin a confined nonleaky aquifer. Summarize the field hydrogeo-logic conditions and the field equipment and instrumen
43、tationincluding the construction of the control well, the method ofmeasurement of discharge rate, and the duration of the test.Discuss rationale for using the constant drawdown method.9.1.2 Conceptual ModelReview the information availableon the hydrogeology of the site; interpret and describe thehyd
44、rogeology of the site as it pertains to the selection of thismethod for conducting and analyzing an aquifer test. Comparethe hydrogeologic characteristics of the site as it conforms anddiffers from the assumptions in the solution of the aquifer testmethod.9.1.3 EquipmentReport the field installation
45、 and equip-ment for the test, including the construction, diameter, depth ofscreened and gravel packed intervals, and location of thecontrol well and discharge measurement device.9.1.4 InstrumentationDescribe the field instrumentationfor observing water levels, discharge rate, barometric changes,and
46、 other environmental conditions pertinent to the test.Include a list of measuring devices used during the test, themanufacturers name, model number, and basic specificationsfor each major item, and the name and date of the lastcalibration, if applicable.9.1.5 Testing ProceduresState the steps taken
47、in conduct-ing pretest, discharge, and recovery phases of the test. Includethe frequency of measurements of discharge rate and otherenvironmental data recorded during the testing procedure.9.2 Presentation and Interpretation of Test Results:9.2.1 DataPresent tables of data collected during the test.
48、9.2.2 Data PlotsPresent data plots used in the analysis ofdata. Show overlays of data plots and type curve with matchpoints and corresponding values of parameters at match points.9.2.3 Evaluate qualitatively the overall accuracy of the test,accuracy of observations, conformance of the hydrogeologicc
49、onditions to the conceptual model assumptions.10. Precision and Bias10.1 PrecisionTest data on precision is not presented dueto the nature of this test method. It is either not feasible or tooNOTE 1After Lohman,4Plate 1.FIG. 2 Logarithmic Plot of Versus G()D5855/D5855M 154costly at this time to have ten or more agencies participate inan in situ testing program at a given site.10.2 BiasThere is no accepted reference value for thi
