1.1 本试验方法描述了使用现场介电常数探头测量土壤和土壤骨料每单位体积的水质量的程序。在由探头设计确定的土壤表面下方的深度进行测量。 1.1.1 有关限制，请参阅第节 6. 关于干扰。 1.2 将介电常数探头插入在被测土壤中钻孔或打孔的孔中。顾名思义，探头测量其所在土壤的介电常数。连接到振荡电路的两个电极相隔预定距离安装。这些电极充当电容器的极板，极板之间的土壤形成电容器电介质。 1.2.1 探针电路在土壤中产生振荡电场。土壤介电常数的变化由电路工作频率的变化表示。由于水的介电常数（80）远高于周围土壤（通常约为4），因此水含量可以通过数学函数与介电常数的变化以及电路工作频率的变化相关。 1.2.2 本试验方法中所述装置的结构、部署和工作原理不同于其他测量介电常数、体积电导率、复阻抗或电磁阻抗的方法（见试验方法 D6780/D6780M , D7698 和 D7830/D7830M )并将结果与单位体积的水质量和/或含水量相关。 1.2.3 通过介电常数探头测量的土壤含水量是体积含水量，表示为水体积与土壤所占总体积的比值。该量通常由探头以每体积土壤的水质量或每单位体积的水质量为单位进行转换和显示。这种转换是通过将含水量（每体积土壤的水体积）乘以水的密度来实现的。 1.3 工程和施工活动中最常见的含水量称为重量含水量ω，是孔隙中的水质量与固体总质量的比值，以百分比表示。 为了确定该数量，还必须确定测量土壤的体积密度。 1.4 单位- 以国际单位制表示的数值应视为标准。以国际单位制以外的单位报告试验结果不应视为不符合本标准。 1.5 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 . 1.5.1 为了将测量值或计算值与规定限值进行比较，测量值或计算值应四舍五入至规定限值中最接近的小数或有效数字。 1.5.2 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。使用的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；通常的做法是增加或减少报告数据的有效位数，以与这些考虑因素相称。考虑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。 1.6 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。 1.7 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 土壤介电常数探头用于以下用途: 5.1.1 所述试验方法是一种快速、无损的技术，可用于测量土壤和土壤骨料每单位体积的水质量，并可与独立的体积密度测定一起用于测定干密度。 5.1.2 该测试方法用于施工中使用的压实土壤和土壤骨料混合物的质量控制和验收测试，也用于研究和开发。无损性质允许在单个测试位置重复测量并对结果进行统计分析。 5.1.3 体积含水量- 试验方法固有的基本假设是，在由土壤或土壤骨料组成的给定试验场地中，系统测量的介电常数值与土壤或土壤骨料的体积含水量直接相关，并且材料是均匀的。（参见 6. ，“干扰。 ”) 注2: 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 describes the procedures for measuring the water mass per unit volume of soil and soil-aggregate by use of an in situ permittivity probe. Measurements are taken at a depth beneath the surface of the soil determined by the design of the probe. 1.1.1 For limitations see Section 6 on Interferences. 1.2 The permittivity probe is inserted into a hole drilled or punched into the soil being measured. As its name indicates, the probe measures the dielectric permittivity of the soil into which it is placed. Two electrodes, connected to an oscillating circuit, are mounted a predetermined distance apart. These electrodes act as the plates of a capacitor, with the soil between the plates forming the capacitor dielectric. 1.2.1 The probe circuit creates an oscillating electric field in the soil. Changes in the dielectric permittivity of the soil are indicated by changes in the circuit’s operating frequency. Since water has a much higher dielectric constant (80) than the surrounding soil (typically around 4), the water content can be related by a mathematical function to the change in dielectric permittivity, and, consequently, the changes in the circuit’s operating frequency. 1.2.2 The construction, deployment, and operating principle of the device described in this test method differ from other methods that measure the dielectric constant, bulk electrical conductivity, complex impedance, or electromagnetic impedance (see Test Methods D6780/D6780M , D7698 , and D7830/D7830M ) of the soil and relate the results to water mass per unit volume and/or water content. 1.2.3 The water content of the soil measured by the permittivity probe is the volumetric water content, expressed as the ratio of the volume of water to the total volume occupied by the soil. This quantity is often converted, and displayed, by the probe in units of mass of water per volume of soil, or water mass per unit volume. This conversion is performed by multiplying the water content (in volume of water per volume of soil) by the density of water. 1.3 Water content most prevalent in engineering and construction activities is known as the gravimetric water content, ω, and is the ratio of the mass of the water in pore spaces to the total mass of solids, expressed as a percentage. To determine this quantity, the bulk density of the soil under measurement must also be determined. 1.4 Units— The values stated in SI units are to be regarded as the standard. Reporting the test 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 rounding established in Practice D6026 . 1.5.1 For purposes of comparing, a measured or calculated value(s) with specified limits, the measured or calculated value(s) shall be rounded to the nearest decimal or significant digits in the specified limits. 1.5.2 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally 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 commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design. 1.6 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. ====== Significance And Use ====== 5.1 The soil permittivity probe is used for the following purposes: 5.1.1 The test method described is useful as a rapid, nondestructive technique for bulk measurements of the water mass per unit volume of soil and soil-aggregate which may, in conjunction with an independent bulk density determination, be used in the determination of dry density. 5.1.2 The test method is used for quality control and acceptance testing of compacted soil and soil-aggregate mixtures as used in construction and also for research and development. The nondestructive nature allows repetitive measurements at a single test location and statistical analysis of the results. 5.1.3 Volumetric Water Content— The fundamental assumptions inherent in the test method are that the dielectric constants value measured by the system in a given test site composed of soil or soil-aggregate are directly correlated to the volumetric water content of the soil or soil-aggregate, and that the material is homogeneous. (See 6 , “Interferences.”) 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.