1.1 这些试验方法描述了确定完整、扰动、重塑和重组（压实）土壤样本的总密度/湿密度/体积密度、干密度和干容重的两种方法( 注1 ). 完整样本可从薄壁取样管、块状样品或土块中获得。通过动态或静态压实程序重塑的试样也通过这些方法进行测量。这些方法适用于在测量过程中保持形状的土壤，也可适用于其他材料，如水泥土、石灰土、膨润土或固化的膨润土水泥浆。密度通常小于基于管或模具体积的值，或从采样管和压实模具中取出样本后的原位条件的值。这种变化是由于消除侧向压力后试样膨胀引起的。 注1: 形容词total、weat、wet或bulk用于表示密度条件。 在土壤科学和地质学等专业中，“体积密度”一词通常与干密度具有相同的含义。在岩土工程和土木工程专业中，当指每单位总体积的部分饱和或饱和土壤或岩石的总质量时，首选形容词为“总过湿和体积”。有关术语密度的更多详细信息，请参阅术语 D653 . 1.1.1 方法A（水置换）- 将试样涂上蜡，然后放入水中，通过测定置换的水量来测量体积。然后根据质量和体积测量值计算密度和单位重量。如果试样易受表面蜡侵入，请勿使用此方法。 1.1.2 方法B（直接测量）- 测量试样的尺寸和质量。然后使用这些直接测量值计算密度和单位重量。通常，试样为圆柱形或长方体。 完整和重组/重塑试样可通过该方法结合强度、渗透性/导水性（空气/水）和压缩性测定进行测试。 1.2 单位- 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。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。 1.2.1 在处理英寸磅单位时，使用英寸磅单位的重力系统。在该系统中，磅（lbf）表示力（重量）的单位，而质量的单位是段塞。除非涉及动态（F=ma）计算，否则未给出缓动单元。 1.2.2 工程/建筑行业的常见做法是同时使用磅来表示质量单位（lbm）和力（lbf）。这种做法隐含地结合了两个独立的单位制； 绝对系统和引力系统。在一个标准中结合使用两套独立的英寸-磅单位在科学上是不可取的。如前所述，本标准包括英寸-磅单位的重力系统，不使用/表示段塞质量单位。然而，使用天平和天平记录质量磅（lbm）或记录密度（lbm/ft） 3. 不应视为不符合本标准。 1.2.3 术语密度和单位重量经常互换使用。密度是单位体积的质量，而单位重量是单位体积的力。在本标准中，密度仅以国际单位制表示。密度确定后，单位重量以国际单位制或英寸-磅单位计算，或以两者为单位计算。 1.3 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 ，除非被本试验方法取代。 1.3.1 本标准中用于规定如何收集/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。 1.4 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。 1.5 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 密度是土壤和岩石的相关系、相关系或质量-体积关系中的一个关键因素( 附录X1 ). 当颗粒密度，即比重（试验方法 D854 )众所周知，干密度可用于计算孔隙度和孔隙比（参见 附录X1 ). 干密度测量也可用于确定土壤压实度。由于含水量是可变的，除在采样时估计每单位体积的土壤重量（例如，克每立方厘米）外，总/湿土壤密度提供的有用信息很少。由于土壤体积随着膨胀土的干燥而收缩，总密度将随含水量而变化。因此，应在采样时确定土壤的含水量。 5.2 重塑/再造样本的密度和单位重量通常用于评估填土、路堤等的压实度。 干密度值用于计算干容重值，以创建压实曲线（试验方法 D698 和 D1557 ). 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。可靠的结果取决于几个因素；实践 D3740 提供了一种评估其中一些因素的方法。

1.1 These test methods describe two ways of determining the total/moist/bulk density, dry density, and dry unit weight of intact, disturbed, remolded, and reconstituted (compacted) soil specimens ( Note 1 ). Intact specimens may be obtained from thin-walled sampling tubes, block samples, or clods. Specimens that are remolded by dynamic or static compaction procedures are also measured by these methods. These methods apply to soils that will retain their shape during the measurement process and may also apply to other materials such as soil-cement, soil-lime, soil-bentonite or solidified soil-bentonite-cement slurries. It is common for the density to be less than the value based on tube or mold volumes, or of in situ conditions after removal of the specimen from sampling tubes and compaction molds. This change is due to the specimen swelling after removal of lateral pressures. Note 1: The adjectives total, moist, wet or bulk are used to represent the density condition. In some professions, such as Soil Science and Geology, the term “bulk density” usually has the same meaning as dry density. In the Geotechnical and Civil Engineering professions, the preferred adjective is total over moist and bulk when referring to the total mass of partially saturated or saturated soil or rock per unit total volume. For more detailed information regarding the term density, refer to Terminology D653 . 1.1.1 Method A (Water Displacement)— A specimen is coated in wax and then placed in water to measure the volume by determining the quantity of water displaced. The density and unit weight are then calculated based on the mass and volume measurements. Do not use this method if the specimen is susceptible to surface wax intrusion. 1.1.2 Method B (Direct Measurement)— The dimensions and mass of a specimen are measured. The density and unit weight are then calculated using these direct measurements. Usually, the specimen has a cylindrical or cuboid shape. Intact and reconstituted/remolded specimens may be tested by this method in conjunction with strength, permeability/hydraulic conductivity (air/water) and compressibility determinations. 1.2 Units— 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. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 1.2.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In the system, the pound (lbf) represents a unit of force (weight), while the units for mass is slugs. The slug unit is not given, unless dynamic (F = ma) calculations are involved. 1.2.2 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This practice implicitly combines two separate systems of units; the absolute and the gravitational systems. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit of mass. However, the use of balances and scales recording pounds of mass (lbm) or recording density in lbm/ft 3 shall not be regarded as nonconformance with this standard. 1.2.3 The terms density and unit weight are often used interchangeably. Density is mass per unit volume, whereas unit weight is force per unit volume. In this standard, density is given only in SI units. After the density has been determined, the unit weight is calculated in SI or inch-pound units, or both. 1.3 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 , unless superseded by this test method. 1.3.1 The procedures used to specify how data are collected/recorded or calculated in this 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. 1.4 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. 1.5 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 Density is a key element in the phase relations, phase relationships, or mass-volume relationships of soil and rock ( Appendix X1 ). When particle density, that is, specific gravity (Test Methods D854 ) is also known, dry density can be used to calculate porosity and void ratio (see Appendix X1 ). Dry density measurements are also useful for determining degree of soil compaction. Since water content is variable, total/moist soil density provides little useful information except to estimate the weight of soil per unit volume, for example, grams per cubic centimeter, at the time of sampling. Since soil volume shrinks with drying of swelling soils, total density will vary with water content. Hence, the water content of the soil should be determined at the time of sampling. 5.2 Densities and unit weights of remolded/reconstituted specimens are commonly used to evaluate the degree of compaction of earthen fills, embankments, and the like. Dry density values are used to calculate dry unit weight values to create a compaction curve (Test Methods D698 and D1557 ). 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 several factors; Practice D3740 provides a means of evaluating some of these factors.