ASTM D5855-1995(2006) Standard Test Method for (Analytical Procedure) for Determining Transmissivity and Storage Coefficient of Confined Nonleaky or Leaky Aquifer by Constant Drawd.pdf

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1、Designation: D 5855 95 (Reapproved 2006)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 D 5855; the number immedia

2、tely 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This t

3、est 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 wi

4、th thefield procedure in Practice D 5786.1.3 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 This standard does not purport to ad

5、dress 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 653 Termin

6、ology Relating to Soil, Rock, and ContainedFluidsD 4043 Guide for Selection of Aquifer Test Method inDetermining Hydraulic Properties by Well TechniquesD 5786 Practice for (Field Procedure) for Constant Draw-down Tests in Flowing Wells for Determining HydraulicProperties of Aquifer Systems3. Termino

7、logy3.1 Definitions:3.1.1 For definitions of terms used in this test method seeTerminology D 653.3.2 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 nd.3.2.4 J0 Besse

8、l 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.3.2.11 Sstorage coefficient n

9、d.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 been shut-in for a period of time, the wel

10、l 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.Data are analyzed by plotting the discharge r

11、ate 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 involved in conducting a constant drawdowntest

12、is given in Practice D 5786. Methods used to develop a conceptualmodel of the site and for initially selecting an analytical procedure aredescribed in Guide D 4043.4.2 Leaky Aquifer SolutionThe solution is given by Han-tush.3Transmissivity is calculated as follows:NOTE 2These are Eq (93) through (97

13、) of Lohman.41This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Sept. 15, 2006. Published January 2007. Originallyapproved in 1995. Last previo

14、us edition approved in 2000 as D 5855 95 (2000).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.3Hantush, M.

15、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, 1972.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken

16、, PA 19428-2959, United States.T 5Q2psWG a,rW/ B!L2T21# (1)where:a5TtSrW2nd (2)rW/B 5 rWT/K8 /b8!#20.5L2# (3)and:GFrWBG5FrWBGFK1rw/b!K0rW/b!G1rp2expF2aSrWBD2G. (4)*o u exp2au2!J02u! 1 Y02u!duu21 rW/B!2nd4.2.1 Storage coefficient is given by:S 5TtrW2and (5)4.3 Non-Leaky Aquifer:4.3.1 Log-LogThe solut

17、ion is given by Lohman.4NOTE 3These equations are Eq (66) through (69) of Lohman.44.3.1.1 Transmissivity is calculated as follows:T 5Q2pGa!sWL2T21# (6)where:a5TtSrW2nd (7)and:Ga! 54ap*oxe2ax2Fp21 tan21SYox!Jox!DGdx nd (8)4.3.1.2 Storage coefficient is given by:S 5TtarW2nd (9)4.3.2 Semi-LogThe soluti

18、on is given by Jacob and Lo-hman.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-lo

19、garithmicmethod 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 (7

20、1) and (73) of Lohman.4T 52.304pDsW/Q!/Dlog10t/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(1)NOTE 6In (Eq 10) and (Eq 11), Q is in cubic feet per day, t is in days.5. Significance and Use5.1 AssumptionsLe

21、aky 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 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

22、control well is constant,5.2.2 Well is infinitesimal diameter and fully penetratesaquifer,5.2.3 The aquifer is homogeneous, isotropic, and areallyextensive,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 Impli

23、cations 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 hydraulic conductivity for theaquifer adjacent to the open interval o

24、f 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 coeffi-cient values calculated from control well data are not reli

25、able.6. Apparatus6.1 Analysis of data from the field procedure (see PracticeD 5786) by the methods specified in this procedure requiresthat the control well and observation wells meet the specifica-tions given in the apparatus section of Practice D 5786.7. Procedure7.1 Data CollectionProcedures to c

26、ollect the field dataused by the analytical procedures described in this test methodare given in Practice D 5786.7.2 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. Cal

27、culation 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.35Jacob, C. E. and Lohman, S. W., “Nonsteady Flow to a Well of ConstantDrawdown in an Extensive Aquifer,” Americ

28、an Geophysical Union Transactions,Vol 33, No. 4, 1952, pp. 552569.D 5855 95 (2006)28.1.2 ProcedureThe graphical procedure is based on thefunctional relations between G(a,rW/B) and a.8.1.2.1 Plot values of G(a,rW/B) versus a at a logarithmicscale.This plot is referred to as the type curve plot.An exa

29、mpleof 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 coordinate.8.1.2.3 Overlay the data plot on the type curve plot and,while the

30、 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 the plots. Record the values of G(a,rW/B), a, Q, and t.For convenience th

31、e point may be selected where G(a,rW/B)and a 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 Solution:8.2.1 (Eq 8) cannot be integrated directly but has beenevaluated

32、numerically and the values are given in Table 7 ofLohman.48.2.2 ProcedureThe graphical procedure is based on re-lationships of Q/sWand t/rW2.8.2.2.1 Plot values G (a) versus a at a logarithmic scale.This plot is referred to as the type curve plot. An example ofthis type curve is given in Fig. 2, tha

33、t is after Plate 1 ofLohman.48.2.2.2 On logarithmic tracing paper of the same scale 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 th

34、e data plot to align with the type curve.8.2.2.4 Select and record the values of an arbitrary point,referred to as the match point, anywhere on the overlappingpart of the plots. Record values of G(a), a, Q/sWand t/rW2,oralternatively G(a), a,Qand t.8.2.2.5 Using the coordinates of the match point, d

35、eterminethe transmissivity and storage coefficient from (Eq 8) and (Eq9).8.3 Non-Leaky 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

36、plot is given in Fig. 3, that isNOTE 1After Lohman5, Plate 5.FIG. 1 Logarithmic Plot of a Versus G(a, rW/B )NOTE 1After Lohman5, Plate 1.FIG. 2 Logarithmic Plot of a Versus G(a)D 5855 95 (2006)3after Fig. 17 of Lohman.4The tabulated data used for this plotare shown in Table 1, that is after Table 8

37、of Lohman.48.3.1.2 From this semilogarithmic plot, determine sW/Q,D(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. Report9.1 Report the following information:9.1.1 IntroductionThe introductory section is intended top

38、resent 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 construction of the control well, the method ofmeas

39、urement 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 site as it pertains to the selection of thismethod for

40、 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.FIG. 3 Semilogarithmic Plot of sw/Q Versus t/rw2TABLE 1 Field Data for Flow Test on Artesia Heights Well NearGrand

41、Junction, CO., September 22, 1948NOTE 1Valve opened at 10:29 a.m. sw= 92.33 ft; rw= 0.276 ft. Datafrom Lohman (1965, Tables 6 and 7, Well 28).Time ofObservationRate ofFlow(gpm)FlowInterval(min)Total FlowDuringInterval(gal)TimeSinceFlowStarted(min)swQ(ftgal1min)trw2(minft2)10:30 7.28 1 7.28 1 12.7 13

42、.110:31 6.94 1 6.94 2 13.3 26.310:32 6.88 1 6.88 3 13.4 39.410:33 6.28 1 6.28 4 14.7 52.610:34 6.22 1 6.22 5 14.8 65.710:35 6.22 1 6.22 6 15.1 78.810:37 5.95 2 11.90 8 15.5 10510:40 5.85 3 17.55 11 15.8 14510:45 5.66 5 28.30 16 16.3 21010:50 5.50 5 27.50 21 16.8 27610:55 5.34 5 26.70 26 17.3 34211:0

43、0 5.34 5 26.70 31 17.3 40711:1012 5.22 10.5 54.81 41.5 17.7 34511:20 5.14 9.5 48.83 51 18.0 67011:30 5.11 10 51.10 61 18.1 80211:45 5.05 15 75.75 76 18.3 99912:00 (noon) 5.00 15 75.00 91 18.5 119612:12 4.92 12 59.04 103 18.8 135412:22 4.88 11 53.68 113 18.9 1485TotalA114 596.98A596.98 gal per 114 mi

44、n = 5.23 gal min1, weighted average discharge.D 5855 95 (2006)49.1.3 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 Instrume

45、ntationDescribe the field instrumentationfor observing water levels, 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,

46、 and the name and date of the lastcalibration, if applicable.9.1.5 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

47、Presentation and Interpretation of Test Results:9.2.1 DataPresent 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

48、 qualitatively the overall accuracy of the test,accuracy of observations, conformance of the hydrogeologicconditions to the conceptual model assumptions.10. Precision and Bias10.1 It is not practicable to specify the precision of this testmethod because the response of aquifer systems during aquifer

49、tests is dependent upon ambient system stresses. The biascaused by the use of the semi-logarithmic method was previ-ously noted. No other statement can be made about biasbecause no true reference values exist.11. Keywords11.1 aquifers; aquifer tests; control wells; ground water;observation wells; storage coefficient; transmissivityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard