1.1 本指南涵盖了使用手动方法确定大于0.45μm范围内河流沉积物颗粒尺寸分布的方法选择。手动方法是指需要操作员进行一些实际测量和计算的方法。自动化方法是在制备样品并将其插入仪器后，由仪器（机器）进行测量和计算，而不是由操作员进行。本指南中并未介绍所有手动方法。然而，在可用的情况下，对于每个粒径范围，至少给出了两种方法。 1.2 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。 1.3 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。 1.4 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 本指南具有通用性，有助于用户确定用于确定河流沉积物粒度分布的适当手动测试方法。本指南中未描述建议的测试方法，但提供了参考文献，以便用户可以获得有关每种测试方法的更多信息。 5.2 应注意的是，不同的测试方法可能而且往往会对同一样品产生不同的粒度分布。这部分是由于需要天然水或蒸馏水的不同试验方法、所用分散方法的差异以及试验方法测量的内容（即物理直径或沉降直径）的差异。

1.1 This guide covers the selection of methods for determining the size distribution of fluvial sediments particles in the range greater than 0.45 μm using manual methods. Manual methods are defined as those methods that require the operator to do some actual measurements and calculations. An automated method would be one which, after the sample is prepared and inserted into an instrument, the instrument (machine) does the measuring and calculations, not the operator. Not all manual methods are presented in this guide. However, where available, at least two methods for each particle size range are given. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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. 1.4 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 guide is general and useful in helping the user to determine an appropriate manual test method for determining the particle size distribution of fluvial sediments. The suggested test methods are not described in this guide, but references are given so that the user may obtain more information about each test method. 5.2 It should be noted that different test methods may and often times do produce different particle size distributions for the same sample. This is due in part to the different test methods requiring native or distilled water, differences in dispersion methods used, and differences in what the test method is measuring, that is, physical or sedimentation diameter.