1.1 本试验方法包括现场测量导水率（也称为 渗透系数 )使用套管钻孔技术测量多孔材料。当可以假设各向同性条件并采用冲洗钻孔时，该方法得出多孔材料的水力传导率。当无法假设各向同性条件时，如果进行单阶段，该方法会产生垂直方向（上限）的导水率极限值，如果进行第二阶段，则会产生水平方向（下限）的导水率极限值。 对于各向异性条件，实际导水率的确定需要合格人员进行进一步分析。 1.2 本试验方法可用于地下水位以上或以下的压实填土或自然沉积物，其平均导水率小于或等于1×10 –5 米/秒（1×10 –3 厘米/秒）。 1.3 导水率大于1×10 –5 m/s可通过普通钻孔测试确定，例如，美国填海局7310 ( 1. ) 2. ; 然而，所得值是表观电导率。 1.4 对于本试验方法，必须区分“饱和”( K s )和“场饱和”( K fs公司 )水力传导率。真正的饱和条件很少发生在渗流区，除非不渗透层导致存在高位地下水位。在渗透事件期间或衬砌池塘发生泄漏时，会出现“现场饱和”情况。由于截留的空气，不会出现真正的饱和 ( 2. ) . 截留的空气阻止水在充满空气的孔隙中移动，与不存在截留空气的情况相比，这可能会将现场测量的导水率降低两倍 ( 3. ) . 该试验方法形成了“现场饱和”条件。 1.5 该试验方法的经验主要用于饱和度为70的材料 % 或更高，并且压实的分层或平面相对水平。它在其他情况下的使用应视为实验性的。 1.6 与所有导水率测试一样，该测试的结果仅适用于渗透土壤的体积。将结果推广到周围地区需要多次测试和合格人员的判断。 所需测试的数量取决于其他因素:区域的大小、该区域内材料的均匀性以及多次测试数据的变化。 1.7 以国际单位制表示的数值应视为标准值。括号中给出的值仅供参考，不被视为标准值。 1.8 所有观察值和计算值应符合实践中制定的有效数字和舍入指南 D6026 . 1.8.1 本标准中用于规定如何收集、记录和计算数据的程序被视为行业标准。 此外，它们代表了通常应保留的有效数字。这些程序不考虑材料变化、获取数据的目的、特殊目的研究或用户目标的任何考虑因素。增加或减少报告数据的有效位数以符合这些考虑是常见做法。工程设计分析方法中使用的有效数字超出了本标准的范围。 1.9 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 该测试方法也无意解决环境保护问题。 1.10 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法提供了一种测量各向同性材料的导水率以及各向异性材料的最大垂直导水率和最小水平导水率的方法，尤其是在与细粒粘土相关的低范围内，1×10 –7 m/s至1×10 –11 米/秒。 5.2 本试验方法适用于测量通过土壤水力屏障的液体流量，例如用于废物围堵设施的压实粘土屏障、用于渠道和水库衬砌、用于渗透覆盖层的液体流量，以及用于保留池或储罐的改良土壤衬砌。 由于推导极限水力传导率方程时使用的边界条件假设，测试单元的厚度必须至少为600 mm。如果被测材料下面有渗透性差得多的材料，则该要求增加到800 mm。 5.3 被测土层必须具有足够的凝聚力，以便在钻孔开挖过程中保持开放状态。 5.4 本试验方法提供了一种测量中等体积土壤渗透速率的方法。大体积土壤的试验比小体积土壤的试验更具代表性。 适当间隔的多个装置提供了更大的体积和空间可变性的指示。 5.5 当被测土层的导水率和孔隙空间分布均匀时，以及当土层的上下边界条件明确时，从该试验方法获得的数据最有用。 5.6 水温变化可能会导致流量测量误差。温度变化导致水位波动，与流量无关。 当在导水率为5×10的土壤中使用小直径立管或万豪瓶时，这个问题最为明显 –10 米/秒或更少。 5.7 使用温度效应计（TEG）考虑温度变化和其他环境扰动的影响，TEG是一个相同的装置，在外壳底部具有防水密封。 5.8 如果待测土壤稍后将承受更大的表土应力，则预计导水率将随着表土应力的增加而降低。 建议进行实验室导水率试验或在不同表面荷载下进行这些试验，以研究应力水平对土壤水力特性的影响 ( 7. ) . 注1: 本标准产生的结果的质量取决于执行该标准的人员的能力，以及所用设备和设施的适用性。符合实践标准的机构 D3740 通常认为能够胜任和客观的测试/采样/检查等。本标准的用户应注意遵守惯例 D3740 本身并不能保证可靠的结果。可靠的结果取决于许多因素；实践 D3740 提供了一种评估其中一些因素的方法。

1.1 This test method covers field measurement of hydraulic conductivity (also referred to as coefficient of permeability ) of porous materials using a cased borehole technique. When isotropic conditions can be assumed and a flush borehole is employed, the method yields the hydraulic conductivity of the porous material. When isotropic conditions cannot be assumed, the method yields limiting values of the hydraulic conductivity in the vertical direction (upper limit) if a single stage is conducted and the horizontal direction (lower limit) if a second stage is conducted. For anisotropic conditions, determination of the actual hydraulic conductivity requires further analysis by qualified personnel. 1.2 This test method may be used for compacted fills or natural deposits, above or below the water table, that have a mean hydraulic conductivity less than or equal to 1×10 –5 m/s (1×10 –3 cm/s). 1.3 Hydraulic conductivity greater than 1×10 –5 m/s may be determined by ordinary borehole tests, for example, U.S. Bureau of Reclamation 7310 ( 1 ) 2 ; however, the resulting value is an apparent conductivity. 1.4 For this test method, a distinction must be made between “saturated” ( K s ) and “field-saturated” ( K fs ) hydraulic conductivity. True saturated conditions seldom occur in the vadose zone except where impermeable layers result in the presence of perched water tables. During infiltration events or in the event of a leak from a lined pond, a “field-saturated” condition develops. True saturation does not occur due to entrapped air ( 2 ) . The entrapped air prevents water from moving in air-filled pores, which may reduce the hydraulic conductivity measured in the field by as much as a factor of two compared with conditions when trapped air is not present ( 3 ) . This test method develops the “field-saturated” condition. 1.5 Experience with this test method has been predominantly in materials having a degree of saturation of 70 % or more, and where the stratification or plane of compaction is relatively horizontal. Its use in other situations should be considered experimental. 1.6 As in the case of all tests for hydraulic conductivity, the results of this test pertain only to the volume of soil permeated. Extending the results to the surrounding area requires both multiple tests and the judgment of qualified personnel. The number of tests required depends on among other things: the size of the area, the uniformity of the material in that area, and the variation in data from multiple tests. 1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard. 1.8 All observed and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026 . 1.8.1 The procedures in this standard that are used to specify how data are collected, recorded, and calculated are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the objectives of the user. Increasing or reducing the significant digits of reported data to be commensurate with these considerations is common practice. Consideration of the significant digits to be used in analysis methods for engineering design is beyond the scope of this standard. 1.9 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. This test method does not purport to address environmental protection problems, as well. 1.10 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. ====== Significance And Use ====== 5.1 This test method provides a means to measure the hydraulic conductivity of isotropic materials and the maximum vertical and minimum horizontal hydraulic conductivities of anisotropic materials, especially in the low ranges associated with fine-grained clayey soils, 1×10 –7 m/s to 1×10 –11 m/s. 5.2 This test method is useful for measuring liquid flow through soil hydraulic barriers, such as compacted clay barriers used at waste containment facilities, for canal and reservoir liners, for seepage blankets, and for amended soil liners, such as those used for retention ponds or storage tanks. Due to the boundary condition assumptions used in deriving the equations for the limiting hydraulic conductivities, the thickness of the unit tested must be at least 600 mm. This requirement is increased to 800 mm if the material being tested is underlain by a material that is far less permeable. 5.3 The soil layer being tested must have sufficient cohesion to stand open during excavation of the borehole. 5.4 This test method provides a means to measure infiltration rate into a moderately large volume of soil. Tests on large volumes of soil can be more representative than tests on small volumes of soil. Multiple installations properly spaced provide a greater volume and an indication of spatial variability. 5.5 The data obtained from this test method are most useful when the soil layer being tested has a uniform distribution of hydraulic conductivity and of pore space and when the upper and lower boundary conditions of the soil layer are well defined. 5.6 Changes in water temperature can introduce errors in the flow measurements. Temperature changes cause fluctuations in the water levels that are not related to flow. This problem is most pronounced when a small diameter standpipe or Marriotte bottle is used in soils having hydraulic conductivities of 5×10 –10 m/s or less. 5.7 The effects of temperature changes and other environmental perturbations are taken into account using a temperature effect gauge (TEG), which is an identical installation with a watertight seal at the bottom of the casing. 5.8 If the soil being tested will later be subjected to increased overburden stress, then the hydraulic conductivities can be expected to decrease as the overburden stress increases. Laboratory hydraulic conductivity tests or these tests under varying surface loads are recommended to study the influence of level of stress on the hydraulic properties of the soil ( 7 ) . Note 1: 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.