1.1 本指南回顾了测定非饱和土壤和沉积物中水力传导率的试验方法。描述了测定现场饱和和非饱和导水率的试验方法。 1.2 现场渗透系数测量用于估计水通过粘土衬垫的运动速度，以确定其是否是水通量的障碍，表征废物处理场下方的水运动，以预测污染物的运动，并测量土壤和沉积物中的渗透和排水，以供各种应用。需要使用测试方法来测量从1 × 10 −2. 至1 × 10 −8. 厘米/秒，适用于表层和次表层，以及两个场- 饱和和非饱和流。 1.3 对于这些现场测试方法，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 ( 1. ) . 2. 截留的空气阻止水在充满空气的孔隙中移动，反过来，与不存在截留空气的情况相比，可能会将现场测量的导水率降低两倍 ( 2. ) . 现场测试方法应模拟“现场- 饱和”条件。 1.4 通常用于确定现场饱和导水率的现场测试方法包括各种双环渗透仪测试方法、空气渗透仪测试方法和钻孔渗透仪测试。许多经验试验方法用于根据每种试验方法获得的数据计算导水率。提供了每种试验方法的一般说明和影响适用性的特殊特性。 1.5 用于确定现场非饱和导水率的现场试验方法包括直接测量技术和各种估计方法。确定非饱和导水率的直接测量技术包括瞬时剖面（IP）测试方法和石膏结皮法。 利用钻孔渗透仪数据和解吸曲线（含水量与基质电位相关的曲线）获得的数据开发了估算技术。 1.6 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.7 所有观察值和计算值应符合实践中确定的有效数字和舍入准则 D6026 . 1.7.1 本标准中用于指定数据收集、计算或记录方式的方法与数据在设计或其他用途中或两者中的应用精度没有直接关系。如何应用使用本标准获得的结果超出了其范围。 1.8 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和健康实践，并确定监管限制的适用性。 1.9 本指南提供了有组织的信息收集或一系列选项，并不推荐具体的行动方案。本文件不能取代教育或经验，应与专业判断一起使用。并非本指南的所有方面都适用于所有情况。本ASTM标准不代表或取代必须根据其判断给定专业服务的充分性的谨慎标准，也不应在不考虑项目的许多独特方面的情况下应用本文件。 本文件标题中的“标准”一词仅表示该文件已通过ASTM共识程序获得批准。 ====意义和用途====== 5.1 饱和导水率测量的目的多种多样，从垃圾填埋场的设计和粘土衬里的施工到灌溉系统的评估。渗透计通常用于需要通过表面或地下层的渗透或渗滤速率的地方。评估通过池塘衬垫的水运动速率就是此类测量的一个例子。钻孔穿透衬管会使衬管渗透率的测量无效。已经注意到，由于水流的横向发散，小型环形渗透计会产生误差。 因此，建议使用非常大（直径1至2米）的渗滤池来测量粘土衬垫通常需要的非常缓慢的渗滤速率。可以使用进气渗透计代替渗透计测试，以避免气流横向发散。然而，由于必须将圆柱体打入测试介质中，因此引入圆柱体可能会破坏测试的实际土柱，尤其是在结构性土壤中。 5.2 确定饱和导水率的钻孔试验适用于评估水通过地下层的运动速度。对于缓慢渗透层，需要开发一种精确的方法来测量水进入钻孔的速度。 在这些条件下，建议使用可定期称重的柔性袋作为储液罐。钻孔流出数据的一些数学解决方案是可用的（Stephens等人。 ( 17 ) ，Reynolds等人。 ( 18 ) ，和Philip ( 19 ) ). 5.3 在需要防止污染物流入地下水的地方，设计危险废物填埋场和蓄水池需要有关非饱和流速的信息。在可用的测试方法中，主要差异是成本和结果偏差和精度。瞬时剖面测试方法似乎提供了非常可靠的数据，因为它使用了大量土壤（几立方米），并且是在现场原状土上进行的。然而，一次测试可能需要数千美元。 石膏结壳测试方法虽然比瞬时剖面测试方法更快，但由于测试区域的空间范围较小，因此牺牲了结果的精度。从基本土壤水力函数（如解吸曲线）估算非饱和导水率的方法可能会偏离真实值一个数量级，但在材料之间或不同含水量范围的渗透性相对差异值得关注的情况下，可能会使用这种方法。 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。 本标准的使用者应注意遵守惯例 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 guide covers a review of the test methods for determining hydraulic conductivity in unsaturated soils and sediments. Test methods for determining both field-saturated and unsaturated hydraulic conductivity are described. 1.2 Measurement of hydraulic conductivity in the field is used for estimating the rate of water movement through clay liners to determine if they are a barrier to water flux, for characterizing water movement below waste disposal sites to predict contaminant movement, and to measure infiltration and drainage in soils and sediment for a variety of applications. Test methods are needed for measuring hydraulic conductivity ranging from 1 × 10 −2 to 1 × 10 −8 cm/s, for both surface and subsurface layers, and for both field-saturated and unsaturated flow. 1.3 For these field test methods a distinction is 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 ( 1 ) . 2 The entrapped air prevents water from moving in air-filled pores that, in turn, may reduce the hydraulic conductivity measured in the field by as much as a factor of two compared to conditions when trapped air is not present ( 2 ) . Field test methods should simulate the “field-saturated” condition. 1.4 Field test methods commonly used to determine field-saturated hydraulic conductivity include various double-ring infiltrometer test methods, air-entry permeameter test methods, and borehole permeameter tests. Many empirical test methods are used for calculating hydraulic conductivity from data obtained with each test method. A general description of each test method and special characteristics affecting applicability is provided. 1.5 Field test methods used to determine unsaturated hydraulic conductivity in the field include direct measurement techniques and various estimation methods. Direct measurement techniques for determining unsaturated hydraulic conductivity include the instantaneous profile (IP) test method and the gypsum crust method. Estimation techniques have been developed using borehole permeameter data and using data obtained from desorption curves (a curve relating water content to matric potential). 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.7.1 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard is beyond its scope. 1.8 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 and health practices and determine the applicability of regulatory limitations prior to use. 1.9 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide 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 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. ====== Significance And Use ====== 5.1 Saturated hydraulic conductivity measurements are made for a variety of purposes varying from design of landfills and construction of clay liners to assessment of irrigation systems. Infiltrometers are commonly used where infiltration or percolation rates through a surface or subsurface layer are desired. Evaluation of the rate of water movement through a pond liner is one example of this kind of measurement. Penetration of the liner by a borehole would invalidate the measurement of liner permeability. It has been noted that small-ring infiltrometers are subject to error due to lateral divergence of flow. Therefore, techniques using very large (1 to 2-m diameter) infiltration basins have been recommended for measuring the very slow percolation rates typically needed for clay liners. The air-entry permeameter can be used instead of infiltrometer tests to avoid lateral divergence of flow. However, because a cylinder must be driven into the media tested, the actual soil column tested may be disrupted by introduction of the cylinder, especially in structured soils. 5.2 Borehole tests for determining saturated hydraulic conductivity are applicable for evaluating the rate of water movement through subsurface layers. For slowly permeable layers, an accurate method of measuring the rate of water movement into the borehole will need to be developed. Use of a flexible bag as a reservoir that can be periodically weighed is advisable for these conditions. A number of mathematical solutions for borehole outflow data are available (Stephens et al. ( 17 ) , Reynolds et al. ( 18 ) , and Philip ( 19 ) ). 5.3 Information on unsaturated flow rates is needed to design hazardous waste landfills and impoundments where prevention of flow of contaminants into groundwater is needed. Of the test methods available, the primary differences are cost and resultant bias and precision. The instantaneous profile test method appears to provide very reliable data because it uses a large volume of soil (several cubic metres) and is performed on undisturbed soils in the field. However, a single test can cost several thousand dollars. The gypsum crust test method, although more rapid than the instantaneous profile test method, sacrifices precision of results due to the smaller spatial extent of the tested area. Methods for estimating unsaturated hydraulic conductivity from fundamental soil hydraulic functions like the desorption curves may deviate from true values by an order of magnitude, but may be of use where relative differences in permeability between materials or across water content ranges is of interest. 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 in that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depends on many factors; Practice D3740 provides a means of evaluating some of those factors.