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5.1 Assumptions: 5.1.1 The control well discharges at a constant rate, Q.5.1.2 The control well is of infinitesimal diameter and fully penetrates the aquifer.5.1.3 The aquifer is homogeneous, isotropic, and areally extensive.NOTE 1: Slug and pumping tests implicitly assume a porous medium. Fractured rock and carbonate settings may not provide meaningful data and information.5.1.4 The aquifer remains saturated (that is, water level does not decline below the top of the aquifer).5.1.5 The aquifer is overlain or underlain, or both, everywhere by confining beds individually having uniform hydraulic conductivities, specific storages, and thicknesses. The confining beds are bounded on the distal sides by one of the cases shown in Fig. 1.5.1.6 Flow in the aquifer is two-dimensional and radial in the horizontal plane.5.2 The geometry of the well and aquifer system is shown in Fig. 1.5.3 Implications of Assumptions: 5.3.1 Paragraph 5.1.1 indicates that the discharge from the control well is at a constant rate. Paragraph 8.1 of Test Method D4050 discusses the variation from a strictly constant rate that is acceptable. A continuous trend in the change of the discharge rate could result in misinterpretation of the water-level change data unless taken into consideration.NOTE 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.5.3.2 The leaky confining bed problem considered by the modified Hantush method requires that the control well has an infinitesimal diameter and has no storage. Moench (6) generalized the field situation addressed by the modified Hantush (1) method to include the well bore storage in the pumped well. The mathematical approach that he used to obtain a solution for that more general problem results in a Laplace transform solution whose analytical inversion has not been developed and probably would be very complicated, if possible, to evaluate. Moench (6) used a numerical Laplace inversion algorithm to develop type curves for selected situations. The situations considered by Moench indicate that large well bore storage may mask effects of leakage derived from storage changes in the confining beds. The particular combinations of aquifer and confining bed properties and well radius that result in such masking is not explicitly given. However, Moench ((6), p. 1125) states “Thus observable effects of well bore storage are maximized, for a given well diameter, when aquifer transmissivity Kb and the storage coefficient Ssb are small.” Moench (p. 1129) notes that “...one way to reduce or effectively eliminate the masking effect of well bore storage is to isolate the aquifer of interest with hydraulic packers and repeat the pump test under pressurized conditions. Because well bore storage C will then be due to fluid compressibility rather than changing water levels in the well”...“the dimensionless well bore storage parameter may be reduced by 4 to 5 orders of magnitude.”5.3.3 The modified Hantush method assumes, for Cases 1 and 3 (see Fig. 1), that the heads in source layers on the distal side of confining beds remain constant. Neuman and Witherspoon (7) developed a solution for a case that could correspond to Hantush's Case 1 with K" = O  = S" except that they do not require the head in the unpumped aquifer to remain constant. For that case, they concluded that the drawdowns in the pumped aquifer would not be affected by the properties of the other, unpumped, aquifer when (Neuman and Witherspoon (7) p. 810) time satisfies:5.3.4 Implicit in the assumptions are the conditions that the flow in the confining beds is essentially vertical and in the aquifer is essentially horizontal. Hantush's (8) analysis of an aquifer bounded only by one leaky confining bed suggested that these assumptions are acceptably accurate whereverThat form of relation between aquifer and confining bed properties may also be a useful guide for the case of two leaky confining beds.1.1 This practice covers an analytical procedure for determining the transmissivity and storage coefficient of a confined aquifer taking into consideration the change in storage of water in overlying or underlying confining beds, or both. This practice is used to analyze water-level or head data collected from one or more observation wells or piezometers during the pumping of water from a control well at a constant rate. With appropriate changes in sign, this practice also can be used to analyze the effects of injecting water into a control well at a constant rate.1.2 This analytical procedure is used in conjunction with Test Method D4050.1.3 Limitations—The valid use of the modified Hantush method (1)2 is limited to the determination of hydraulic properties for aquifers in hydrogeologic settings with reasonable correspondence to the assumptions of the Hantush-Jacob method (Practice D6029/D6029M) with the exception that in this case the gain or loss of water in storage in the confining beds is taken into consideration (see 5.1). All possible combinations of impermeable beds and source beds (for example, beds in which the head remains uniform) are considered on the distal side of the leaky beds that confine the aquifer of interest (see Fig. 1).FIG. 1 Cross Sections Through Discharging Wells in Leaky Aquifers with Storage of Water in the Confining Beds, Illustrating Three Different Cases of Boundary Conditions (from Reed (2) )1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.4.1 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering data.1.5 The values stated in SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values for the two systems may result in nonconformance with the standard. Reporting of results in units other than SI shall not be regarded as nonconformance with this standard.1.6 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of the practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without the consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Assumptions: 5.1.1 The control well discharges at a constant rate, Q.5.1.2 The control well is of infinitesimal diameter and fully penetrates the aquifer.5.1.3 The aquifer is homogeneous, isotropic, and areally extensive.NOTE 2: Slug and pumping tests implicitly assume a porous medium. Fractured rock and carbonate settings may not provide meaningful data and information.5.1.4 The aquifer remains saturated (that is, water level does not decline below the top of the aquifer).5.1.5 The aquifer is overlain, or underlain, everywhere by a confining bed having a uniform hydraulic conductivity and thickness. It is assumed that there is no change of water storage in this confining bed and that the hydraulic gradient across this bed changes instantaneously with a change in head in the aquifer. This confining bed is bounded on the distal side by a uniform head source where the head does not change with time.5.1.6 The other confining bed is impermeable.5.1.7 Leakage into the aquifer is vertical and proportional to the drawdown, and flow in the aquifer is strictly horizontal.5.1.8 Flow in the aquifer is two-dimensional and radial in the horizontal plane.5.2 The geometry of the well and aquifer system is shown in Fig. 1.5.3 Implications of Assumptions: 5.3.1 Paragraph 5.1.1 indicates that the discharge from the control well is at a constant rate. Section 8.1 of Test Method D4050 discusses the variation from a strictly constant rate that is acceptable. A continuous trend in the change of the discharge rate could result in misinterpretation of the water-level change data unless taken into consideration.5.3.2 The leaky confining bed problem considered by the Hantush-Jacob solution requires that the control well has an infinitesimal diameter and has no storage. Abdul Khader and Ramadurgaiah (5) developed graphs of a solution for the drawdowns in a large-diameter control well discharging at a constant rate from an aquifer confined by a leaky confining bed. Fig. 2 (Fig. 3 of Abdul Khader and Ramadurgaiah (5)) gives a graph showing variation of dimensionless drawdown with dimensionless time in the control well assuming the aquifer storage coefficient, S = 10−3, and the leakage parameter,Note that at early dimensionless times the curve for a large-diameter well in a non-leaky aquifer (BCE) and in a leaky aquifer (BCD) are coincident. At later dimensionless times, the curve for a large diameter well in a leaky aquifer coalesces with the curve for an infinitesimal diameter well (ACD) in a leaky aquifer. They coalesce about one logarithmic cycle of dimensionless time before the drawdown becomes sensibly constant. For a value of rw/B smaller than 10−3, the constant drawdown (D) would occur at a greater value of dimensionless drawdown and there would be a longer period during which well-bore storage effects are negligible (the period where ACD and BCD are coincident) before a steady drawdown is reached. For values ofgreater than 10−3, the constant drawdown (D) would occur at a smaller value of drawdown and there would be a shorter period of dimensionless time during which well-storage effects are negligible (the period where ACD and BCD are coincident) before a steady drawdown is reached. Abdul Khader and Ramadurgaiah (5)present graphs of dimensionless time versus dimensionless drawdown in a discharging control well for values of S = 10−1, 10−2, 10−3, 10−4, and 10−5 and rw/B = 10−2, 10−3, 10−4, 10−5, 10−6, and 0. These graphs can be used in an analysis prior to the aquifer test making use of estimates of the hydraulic properties to estimate the time period during which well-bore storage effects in the control well probably will mask other effects and the drawdowns would not fit the Hantush-Jacob solution.FIG. 2 Time—Drawdown Variation in the Control Well for S = δ = 10−3 (from Abdul Khader and Ramadurgaiah (5))FIG. 3 Schematic Diagram of Two-Aquifer System5.3.2.1 The time needed for the effects of control-well bore storage to diminish enough that drawdowns in observation wells should fit the Hantush-Jacob solution is less clear. But the time adopted for when drawdowns in the discharging control well are no longer dominated by well-bore storage affects probably should be the minimum estimate of the time to adopt for observation well data.5.3.3 The assumption that the aquifer is bounded, above or below, by a leaky layer on one side and a nonleaky layer on the other side is not likely to be entirely satisfied in the field. Neuman and Witherspoon (6, p. 1285) have pointed out that because the Hantush-Jacob formulation uses water-level change data only from the aquifer being pumped (or recharged) it can not be used to distinguish whether the leaking beds are above or below (or from both sides) of the aquifer. Hantush (7) presents a refinement that allows the parameters determined by the aquifer field test analysis to be interpreted as composite parameters that reflect the combined effects of overlying and underlying confined beds. Neuman and Witherspoon (6) describe a method to estimate the hydraulic properties of a confining layer by using the head changes in that layer.5.3.4 The Hantush-Jacob theoretical development requires that the leakage into the aquifer is proportional to the drawdown, and that the drawdown does not vary in the vertical in the aquifer. These requirements are sometimes described by stating that the flow in the confining beds is essentially vertical and in the aquifer is essentially horizontal. Hantush's (8) analysis of an aquifer bounded only by one leaky confining bed suggested that this approximation is acceptably accurate wherever5.3.5 The Hantush-Jacob method requires that there is no change in water storage in the leaky confining bed. Weeks (9) states that if the “leaky” confining bed is thin and relatively permeable and incompressible, the solution of Hantush and Jacob (2) will apply, whereas the solution of Hantush (7), which is described in Practice D6028/D6028M, that considers storage in confining beds will apply in most cases if one confining bed is thick, of low permeability, and highly compressible. For the case where one layer confining the aquifer is sensibly impermeable, and the other confining bed is leaky and bounded on the distal side by a layer in which the head is constant it follows from Hantush (7) that when time, t, satisfiesthe drawdowns in the aquifer will be described by the equationwhereNote that in Hantush's (7) solution, the termappears instead of the expression given for u in Eq 3, namelyThe implication being from Hantush (7) that after the time criterion given by Eq 9 is satisfied, the apparent storage coefficient of the aquifer will include the aquifer storage coefficient and one third of the storage coefficient for the confining bed. If the storage coefficient of the confining bed is very much less than that of the aquifer, then the effect of storage in the confining bed will be very small or sensibly nil. To illustrate the use of Hantush's time criterion, suppose a confining bed is characterized by b′ = 3 m, K′ = 0.001 m/day, and S′s = 3.6 × 10−6 m−1, then the Hantush-Jacob solution Eq 10 would apply everywhere whenorIf the vertical hydraulic conductivity of the confining bed was an order of magnitude larger, K′ = 0.01 m/day, then the Hantush-Jacob (2) solution would apply when t > 23 min.5.3.5.1 It should be noted that the Hantush (7) analysis assumes that well bore storage is negligible.5.3.5.2 Moench (10) presents numerical results that give insight into the effects of control well storage and changes in storage in the confining bed on drawdowns in the aquifer for various parameter values. However, Moench does not offer an explicit formula for when those effects diminish enough for subsequent drawdown data to fit the Hantush-Jacob solution.5.3.6 The assumption stated in 5.1.5, that the leaky confining bed is bounded on the other side by a uniform head source, the level of which does not change with time, was considered by Neuman and Witherspoon (11, p. 810). They considered a confined system of two aquifers separated by a confining bed as shown schematically in Fig. 3. Their analysis concluded that the drawdowns in an aquifer in response to discharging from a well in that aquifer would not be affected by the properties of the other, unpumped, aquifer for times that satisfy1.1 This practice covers an analytical procedure for determining the transmissivity and storage coefficient of a confined aquifer and the leakance value of an overlying or underlying confining bed for the case where there is negligible change of water in storage in a confining bed. This practice is used to analyze water-level or head data collected from one or more observation wells or piezometers during the pumping of water from a control well at a constant rate. With appropriate changes in sign, this practice also can be used to analyze the effects of injecting water into a control well at a constant rate.1.2 This analytical procedure is used in conjunction with Test Method D4050.1.3 Limitations—The valid use of the Hantush-Jacob method is limited to the determination of hydraulic properties for aquifers in hydrogeologic settings with reasonable correspondence to the assumptions of the Theis nonequilibrium method (Practice D4106) with the exception that in this case the aquifer is overlain, or underlain, everywhere by a confining bed having a uniform hydraulic conductivity and thickness, and in which the gain or loss of water in storage is assumed to be negligible, and that bed, in turn, is bounded on the distal side by a zone in which the head remains constant. The hydraulic conductivity of the other bed confining the aquifer is so small that it is assumed to be impermeable (see Fig. 1).FIG. 1 Cross Section Through a Discharging Well in a Leaky Aquifer (from Reed (1)3). The Confining and Impermeable Bed Locations Can Be Interchanged1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. Reporting of results in units other than SI shall not be regarded as nonconformance with this standard.1.5 All observed and calculated values shall conform to the guidelines for significant digits and round established in Practice D6026, unless superseded by this standard.1.5.1 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported date to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis method for engineering design.1.6 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of the practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without the consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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定价： 910元 / 折扣价： 774 元

This specification deals with consumer safety for clothing storage chests. It is intended to minimize the incidents and injuries to children resulting from normal use and reasonably foreseeable misuse or abuse of these chests. The design of the lid support, closures, and locks shall conform to their performance requirements. Test methods shall be done for lid support mechanisms and closures. Finishes and materials used in the construction of the chests shall be nonhazardous. All paints and coatings shall comply with the limitations of antimony, arsenic, barium, cadmium, chromium, lead, mercury, and selenium.1.1 This consumer safety specification covers the performance requirements and test methods to ensure the safety of chests.1.2 This consumer safety specification is intended to minimize the incidents and injuries to children resulting from normal use and reasonably foreseeable misuse or abuse of these chests.1.3 This consumer safety specification applies to products commonly known as cedar chests, hope chests, blanket chests, and keepsake chests, or other similar closed rigid boxes designed and marketed as sealed storage containers for clothes, blankets, linens, keepsake or other household items. Products subject to these requirements are:1.3.1 Those with a single volume of 1.1 ft3 (0.031 m3) or more measured with all removable shelves or compartments removed from the product, and1.3.2 Those intended to create a tightly sealed storage space when the lid is closed for purposes such as the prevention of insect infestation and dust or dirt contamination.1.4 No chest produced after the approval date of this consumer safety specification shall, either by label or other means, indicate compliance with this specification unless it conforms to all requirements contained herein.1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.6 The following precautionary caveat pertains only to the test methods portion, Section 5, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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