1.1 本规程用于测量实验室用于评估土壤侵蚀的降雨模拟器的动能。雨滴动能是进行土壤侵蚀研究时应考虑的一个重要因素。使用从确定雨滴大小收集的数据，本规程提供了一种统一计算动能的方法，可用于比较不同实验室的结果。 1.2 许多类型的侵蚀控制产品（ECP）在实验室和现场环境中使用降雨模拟器来评估其减少土壤侵蚀的能力。 降雨模拟器与试验区一起使用，以模拟现场正在或可能出现的特定条件。降雨模拟器通常使用雨滴发射器、洒水器或喷嘴来创建雨滴。每个设备产生不同的雨滴，由于可以配置降雨模拟器以产生不同的雨滴大小和高度，动能将不同。因此，必须计算给定条件下的动能，以便正确理解侵蚀对裸土和ECP的影响。 1.3 雨滴大小的上限通常为7毫米。 虽然有时雨滴大小可能在6到7毫米之间，但雨滴大小超过6毫米并不常见。 1.4 单位- 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。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 用于指定如何在标准中收集/记录或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 本实践提供了一组用于执行一个或多个特定操作的说明。 本文件不能取代教育或经验，应与专业判断一起使用。并非本惯例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。 1.7 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。 1.8 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 当雨滴撞击土壤表面时，它会消耗能量并开始撞击- 诱发土壤侵蚀过程。雨滴的动能是影响土壤侵蚀的一个因素。本实践提供了一种量化降雨模拟器产生的动能的方法。 5.2 土壤侵蚀是影响许多行业的一个问题。公路和公路建设行业对边坡防护特别感兴趣。许多ECP制造商依靠使用降雨模拟器对其产品进行测试，以满足不同机构制定的某些规范。 5.3 提供ECP测试的实验室使用降雨模拟器。许多实验室能够调整其降雨模拟器、雨滴的下落高度，甚至可以调整用于模拟预期、预期或实际现场条件的试验地块的坡度。 应测量与模拟器特定配置相关的动能。 5.4 已知给定模拟器配置的动能将提供一种设置最小值和上限值的方法，以便可以在实验室之间进行比较，并能够解释实验室之间的差异。如果存在最小值和上限值，并且实验室之间的雨滴大小在相同范围内，则实验室之间的动能应相似。一旦根据特定标准确定了给定降雨模拟器配置的动能，就可以对这些特定标准的结果进行比较。 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 practice is used to measure the kinetic energy of rainfall simulators used by laboratories to evaluate soil erosion. The kinetic energy of raindrops is an important factor that should be considered when conducting soil erosion studies. Using the data collected from determining the raindrop size, this practice provides a method to uniformly calculate the kinetic energy which can be used to compare results from different laboratories. 1.2 Many types of Erosion Control Products (ECPs) are evaluated for their ability to reduce soil erosion in laboratory and field settings using rainfall simulators. Rainfall simulators are used with test plots to simulate a specific condition that is or may be expected in the field. Rainfall simulators typically use drop emitters, sprinklers, or nozzles to create the raindrops. Each device produces different drops and since the rainfall simulators can be configured to produce different raindrop sizes and fall heights, the kinetic energy will be different. Therefore, the kinetic energy must be calculated for a given set of conditions in order to properly understand the impact of erosion for bare soil and the ECP. 1.3 The upper limit of the size of a raindrop is generally accepted to be 7 mm. While it is possible to get a raindrop size between 6 and 7 mm occasionally, it is not common to get raindrop sizes above 6 mm. 1.4 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Reporting of 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 The procedures used to specify how data are collected/recorded or 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 this standard to consider significant digits used in analysis methods 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 this 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 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. ====== Significance And Use ====== 5.1 When a raindrop impacts the surface of a soil, it expends its energy and begins the impact-induced soil erosion process. This kinetic energy of the raindrop is one factor influencing soil erosion. This practice provides a method to quantify the kinetic energy produced by rainfall simulators. 5.2 Soil erosion is a concern that affects many industries. The highway and road construction industry is particularly interested in slope protection. There are many ECP manufacturers that rely on testing of their products using rainfall simulators to meet certain specifications set forth by different agencies. 5.3 Laboratories that offer testing of ECPs use rainfall simulators. Many laboratories are able to adjust their rainfall simulators, the drop height of the raindrops, and even the slopes of the test plots they use to model expected, anticipated, or actual field conditions. The kinetic energy associated with the specific configuration of the simulator should be measured. 5.4 Knowing the kinetic energy for the given simulator configuration will provide a way to set minimum and upper limit values so that comparisons between laboratories can be made as well as having a way to account for the differences between the laboratories. If there are minimum and upper limit values and the raindrop size is in the same range between laboratories, the kinetic energy between the laboratories should be similar. Once the kinetic energy is established for a given rainfall simulator configuration according to a specific standard, comparisons of the results for those specific standards can be made. 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.