1、Designation: D5855 95 (Reapproved 2013)Standard 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; the number immediate
2、ly following the designation indicates the year oforiginal adoption or, in the case 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 tes
3、t method 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
4、 thefield 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 uni
5、ts or 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 in
6、units 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, ass
7、ociated 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 ContainedFl
8、uidsD4043 Guide for Selection of Aquifer Test Method inDetermining Hydraulic Properties by Well TechniquesD5786 Practice for (Field Procedure) for Constant Draw-down Tests in Flowing Wells for Determining HydraulicProperties of Aquifer SystemsD6026 Practice for Using Significant Digits in Geotechnic
9、alData3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, seeTerminology D653.3.2 Symbols and Dimensions:3.2.1 Ttransmissivity 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 n
10、d.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 nd.3.2.7 uvariable of integration nd.3.2.8 telapsed time test T.3.2.9 Qdischarge rate L3T1.3.2.10 sWconstant drawdown in control well L.1This test me
11、thod 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 March 15, 2013. Published April 2013. Originallyapproved in 1995. Last previous edition approved in 2006 a
12、s D5855 95 (2006).DOI: 10.1520/D5855-95R13.2For 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 Document Summary page onthe ASTM website.*A Summary of Chan
13、ges section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.11 Sstorage coefficient nd.3.2.12 rWradius of control well.4. Summary of Test Method4.1 This test method describes the analytical proce
14、dure foranalyzing data collected during a constant drawdown aquifertest. This test method is usually performed on a flowing well.After the well has 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
15、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.Data are analyzed by plotting the discharge rate versus time.NOTE 1This test method involves the withdrawal of water from acontrol well that is fully scree
16、ned through the confined aquifer. Thewithdrawal rate is varied to cause the water level within the well to remainconstant. The field procedure involved in conducting a constant drawdowntest is given in Practice D5786. Methods used to develop a conceptualmodel of the site and for initially selecting
17、an analytical procedure aredescribed in Guide D4043.4.2 Leaky Aquifer SolutionThe solution is given by Han-tush.3Transmissivity is calculated as follows: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!K0r
18、W/b!G1r2expF2SrWBD2G. (4)* uexp2u2!J02u! 1Y02u!duu21 rW/B!2nd#4.2.1 Storage coefficient is given by:S 5TtrW2nd# (5)4.3 Non-Leaky Aquifer:4.3.1 Log-LogThe 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!sWL2
19、T21# (6)where: 5TtSrW2nd# (7)and:G a! 54*xe2x2F21 tan21SYox!Jox!D Gdx nd# (8)4.3.1.2 Storage coefficient is given by:S 5TtrW2nd# (9)4.3.2 Semi-LogThe solution 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
20、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-logarithmicmethod will produce values of transmissivity that are slightly elevated.Examples of this error are shown below:u W(u)EstimatedError, %0.2
21、5000 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 (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 coef
22、ficient 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 Use5.1 AssumptionsLeaky Aquifer:5.1.1 Drawdown (sW) in the control well is constant,5.1.2 Well is infinitesimal diameter and fully penetratesaquifer,5.1.3 The aquifer
23、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 diameter and fully penetratesaquifer,5.2.3 The aquifer is homogeneous, isotropic, and areallye
24、xtensive,5.2.4 Discharge from the well is derived exclusively fromstorage in the nonleaky 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 b
25、e applied to partially penetrating wells where the methodmay provide an estimate of hydraulic conductivity for theaquifer adjacent to the open interval of the well if the3Hantush, M. S., “Nonsteady Flow to Flowing Wells in LeakyAquifer,” Journalof Geophysical Research, Vol 64, No. 8, 1959, pp. 10431
26、052.4Lohman, S. W., “Ground-Water Hydraulics,” Professional Paper 708, U.S.Geological Survey, 1972.5Jacob, C. E., and Lohman, S. W., “Nonsteady Flow to a Well of ConstantDrawdown in an Extensive Aquifer,” American Geophysical Union Transactions,Vol 33, No. 4, 1952, pp. 552569.D5855 95 (2013)2horizon
27、tal 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 coeffi-cient values calculated from control well data are not reliable.6. Apparatus6.1 Ana
28、lysis 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 Practice D5786.7. Procedure7.1 Data CollectionProcedures to collect the field dataused by
29、 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 Section 8.7.3 ReportPrepare a report as given in Section 9.8. Calculation and Interpretation o
30、f 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 thefunctional relations between G(,rW/B) and .8.1.2.1 Plot values of G(,rW/B) versus at a
31、 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 thetype curve plot values of Q on the vertical coordinate againstt on the horizontal coor
32、dinate.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 of an arbitrary point,referred to as the match point, anywhere on the overlappingpart of
33、the plots. Record the values of G(,rW/B), , Q, and t.For convenience the point may be selected where G(,rW/B)and are integer values.8.1.2.5 Using the coordinates of the match point, determinethe transmissivity and storage coefficient from (Eq 1) and (Eq5).8.2 Non-Leaky Aquifer SolutionLog-Log Soluti
34、on:NOTE 1After Lohman,4Plate 5.FIG. 1 Logarithmic Plot of Versus G(, rW/B )NOTE 1After Lohman,4Plate 1.FIG. 2 Logarithmic Plot of Versus G()D5855 95 (2013)38.2.1 (Eq 8) cannot be integrated directly but has beenevaluated numerically and the values are given in Table 7 ofLohman.48.2.2 ProcedureThe gr
35、aphical procedure is based on rela-tionships of Q/sWand t/rW2.8.2.2.1 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 scal
36、e as thetype curve, plot values of Q/sWversus t/rW2. Alternatively, plotvalues of Q versus t.8.2.2.3 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 and record the values of
37、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) and (Eq9).8.3 Non-Leak
38、y Aquifer SolutionSemi-Log Solution:8.3.1 ProcedureThe graphical procedure is based on therelationships between sW/Q and t/rW2.8.3.1.1 Plot values of sW/Q versus t/rW2on a semilogarith-mic scale. An example of this plot is given in Fig. 3, that isafter Fig. 17 of Lohman.4The tabulated data used for
39、this plotare shown in Table 1, that is after Table 8 of Lohman.48.3.1.2 From this semilogarithmic plot, determine sW/Q,(sW/Q) 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 information:9.1.1
40、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 instrumentationincluding the
41、 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 thehydrogeology of the si
42、te as it pertains to the selection of thismethod for conducting and analyzing an aquifer test. CompareFIG. 3 Semilogarithmic Plot of sw/Q Versus t/rw2D5855 95 (2013)4the hydrogeologic characteristics of the site as it conforms anddiffers from the assumptions in the solution of the aquifer testmethod
43、.9.1.3 EquipmentReport the field installation 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 l
44、evels, discharge rate, barometric changes,and 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
45、.1.5 Testing ProceduresState the steps taken 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 DataPres
46、ent tables of data collected during the test.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 ob
47、servations, conformance of the hydrogeologicconditions 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 toocostly at this time to have ten or more agencies participate in
48、an in situ testing program at a given site.10.2 BiasThere is no accepted reference value for this testmethod, therefore, bias cannot be determined. The bias causedby the use of the semi-logarithmic method was previouslynoted.11. Keywords11.1 aquifers; aquifer tests; control wells; groundwater;observ
49、ation wells; storage coefficient; transmissivitySUMMARY OF CHANGESCommittee D18 has identified the location of selected changes to this standard since the last issue (D5855 95(2006) that may impact the use of this standard. (Approved March 15, 2013.)(1) Revised Section 1 to add reference to Practice D6026 andSignificant Digits.(2) Revised Section 2 to add reference to Practice D6026.(3) Renamed Section 9 to Records.(4) Revised Secti
