1.1 这些试验方法包括使用垂直振动台测定无粘性自由排水土壤的最大指数干密度/单位重量。本标准标题和其余部分省略了形容词“密度或单位重量之前的干燥”，以符合第节给出的适用定义 3. 关于术语。 1.2 单位制: 1.2.1 本标准中所述的测试仪器是使用重量或英寸-磅系统中的数值开发和制造的。因此，以英寸-磅为单位的试验装置尺寸和质量被视为标准。 1.2.2 工程专业中的常见做法是同时使用磅来表示质量单位（lbm）和力单位（lbf）。 这隐含地结合了两个独立的单元系统；也就是说，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。本标准是在处理英寸-磅系统时使用重力单位制编写的。在该系统中，磅（lbf）表示力（重量）的单位。然而，天平或天平测量质量；必须计算重量。在英寸-磅系统中，通常假设1 lbf等于1 lbm。虽然报告密度不被视为不符合本标准，但应计算和报告单位重量，因为结果可用于确定力或应力。 1.2.3 术语密度和单位重量经常互换使用。密度是每单位体积的质量，而单位重量是每单位体积的力。在此标准中，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 提供了四种替代方法来确定最大指数密度/单位重量，如下所示: 1.3.1 方法1A- 使用烘干土壤和电磁垂直振动台。 1.3.2 方法1B- 使用湿土和电磁垂直振动台。 1.3.3 方法2A- 使用烘干土壤和偏心轮或凸轮- 驱动、垂直振动台。 1.3.4 方法2B- 使用湿土和偏心或凸轮驱动的垂直振动台。 1.4 使用的方法应由指定测试的个人指定。 1.4.1 使用的表格类型（方法1或2）可能根据可用设备决定。 注1: 有证据表明，电磁工作台的最大索引密度/单位重量值略高于偏心或凸轮驱动工作台。 1.4.2 建议在开始新工作或遇到土壤类型变化时同时采用干法和湿法（方法1A和1B或2A和2B），因为对于某些土壤，湿法可以产生显著更高的最大指数密度/单位重量值。 当与最小指数密度/单位重量、试验方法一起考虑时，这种更高的最大指数密度 D4254 ，会显著影响相对密度的值( 3.2.8 )计算现场遇到的土壤。虽然干法通常是首选方法，因为通常可以更快地获得结果，但作为一般规则，如果确定其产生的最大指数密度/单位权重将显著影响相对密度值的使用/应用，则应使用湿法。 1.5 这些试验方法适用于可能含有15 %, 按干质量计算，土壤颗粒通过No。 200（75μm）筛，前提是它们仍然具有无粘性、自由排水特性（标称筛尺寸符合规范要求） E11 ). 此外，这些试验方法适用于土壤，其中100 %, 按干质量计算，土壤颗粒通过3英寸。（75 mm）筛。 1.5.1 就这些试验方法而言，土壤应被视为自然产生的无粘性土壤、加工颗粒、或自然土壤的复合物或混合物，或自然颗粒和加工颗粒的混合物，前提是它们是自由排水的。 1.6 这些试验方法通常会产生更高的最大干密度/单位重量，用于无粘性、自由- 排水土壤比通过冲击压实获得的排水土壤，其中定义明确的水分-密度关系不明显。然而，对于一些含5到15%的土壤 % 细粒，冲击压实的使用（试验方法 D698 或 D1557 )可能有助于评估适当的最大指数密度/单位权重。 1.7 这些试验方法产生的最大干密度/单位重量通常低于使用试验方法通过振动锤获得的最大干密度/单位重量 D7382 . 1.8 对于许多类型的自由排水、无粘性土壤，这些试验方法会导致土壤中度退化（颗粒分解）。当发生降解时，获得的最大指数密度/单位重量通常会增加，当使用不同尺寸的模具测试给定土壤时，可能无法获得可比的测试结果。 1.9 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 . 1.9.1 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。 1.9.2 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。 1.10 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。 1.11 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 对于许多无粘性、自由排水的土壤，最大指数密度/单位重量是评估给定土体压实度状态的关键组成部分之一，该土体是自然产生的或在施工期间放置的。 5.1.1 相对密度和压实度通常用于评估给定土体的压实度状态。有时也使用密度/单位重量指数。参见第节 3. 有关术语的描述。 5.2 一般认为，相对密度或压实度是给定土体压实度状态的良好指标。然而，通过各种方法压实到给定压实状态的给定土壤的工程特性，如强度、压缩性和渗透性，可能会有很大的差异。 因此，在将土壤的工程特性与压实状态联系起来时，必须进行大量的工程判断。 5.3 通过这些试验方法不一定能获得绝对最大密度/单位重量。 注2: 此外，有公布的数据表明，这些测试方法具有高度的可变性。 4. 然而，通过仔细校准设备，包括振动台，并仔细注意适当的测试程序和技术，可以大大降低可变性。 注3: 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，被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 本身不能确保可靠的结果。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。 5.4 发现垂直振动的双振幅对获得的密度有显著影响。 4. 对于特定振动台和模具组件，给定材料的最大指数密度/单位重量可以在双振幅振动下获得，而不是在0的双振幅下。 013±0.002英寸。（0.33±0.05 mm），频率为60 Hz或0.019±0.003 in。（0.48±0.08 mm），在本方法要求的50 Hz下；也就是说，干密度/容重最初可能随着双振幅振动的增加而增加，达到峰值，然后随着双振幅振动的进一步增加而降低。此外，峰值密度/容重和最佳双振幅（出现峰值密度/容重的双振幅）之间的关系可能因不同土壤类型和级配而异。 5.5 标准模具的使用( 6.1.1 )对于大多数需要最大指数的土壤来说都是令人满意的- 密度/单位重量测试。特殊模具( 6.1.2 )仅当试验结果与设计或特殊研究结合使用，且土壤不足，无法使用标准模具时，方可使用。应谨慎使用此类试验结果，因为使用特殊模具获得的最大指数密度/单位重量可能与使用标准模具获得的结果不一致。

1.1 These test methods cover the determination of the maximum-index dry density/unit weight of cohesionless, free-draining soils using a vertically vibrating table. The adjective “dry before density or unit weight is omitted in the title and remaining portions of this standard to be consistent with the applicable definition given in Section 3 on Terminology. 1.2 Systems of Units: 1.2.1 The testing apparatus described in this standard has been developed and manufactured using values in the gravimetric or inch-pound system. Therefore, test apparatus dimensions and mass given in inch-pound units are regarded as the standard. 1.2.2 It is common practice in the engineering profession to concurrently use pounds to represent both a unit of mass (lbm) and a unit of force (lbf). This implicitly combines two separate systems of units; that is, the absolute system and the gravitational system. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. This standard has been written using the gravitational system of units when dealing with the inch-pound system. In this system, the pound (lbf) represents a unit of force (weight). However, balances or scales measure mass; and weight must be calculated. In the inch-pound system, it is common to assume that 1 lbf is equal to 1 lbm. While reporting density is not regarded as nonconformance with this standard, unit weights should be calculated and reported since the results may be used to determine force or stress. 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 Four alternative methods are provided to determine the maximum index density/unit weight, as follows: 1.3.1 Method 1A— Using oven-dried soil and an electromagnetic, vertically vibrating table. 1.3.2 Method 1B— Using wet soil and an electromagnetic, vertically vibrating table. 1.3.3 Method 2A— Using oven-dried soil and an eccentric or cam-driven, vertically vibrating table. 1.3.4 Method 2B— Using wet soil and an eccentric or cam-driven vertically vibrating table. 1.4 The method to be used should be specified by the individual assigning the test. 1.4.1 The type of table to be used (Method 1 or 2) is likely to be decided based upon available equipment. Note 1: There is evidence to show that electromagnetic tables yield slightly higher values of maximum index density/unit weight than the eccentric or cam-driven tables. 1.4.2 It is recommended that both the dry and wet methods (Methods 1A and 1B or 2A and 2B) be performed when beginning a new job or encountering a change in soil types, as the wet method can yield significantly higher values of maximum index density/unit weight for some soils. Such a higher maximum index density, when considered along with the minimum index density/unit weight, Test Methods D4254 , will be found to significantly affect the value of the relative density ( 3.2.8 ) calculated for a soil encountered in the field. While the dry method is often preferred because results can usually be obtained more quickly, as a general rule the wet method should be used if it is established that it produces maximum index densities/unit weights that would significantly affect the use/application of the value of relative density. 1.5 These test methods are applicable to soils that may contain up to 15 %, by dry mass, of soil particles passing a No. 200 (75-μm) sieve, provided they still have cohesionless, free-draining characteristics (nominal sieve dimensions are in accordance with Specification E11 ). Further, these test methods are applicable to soils in which 100 %, by dry mass, of soil particles pass a 3-in. (75-mm) sieve. 1.5.1 Soils, for the purpose of these test methods, shall be regarded as naturally occurring cohesionless soils, processed particles, or composites or mixtures of natural soils, or mixtures of natural and processed particles, provided they are free draining. 1.6 These test methods will typically produce a higher maximum dry density/unit weight for cohesionless, free-draining soils than that obtained by impact compaction in which a well-defined moisture-density relationship is not apparent. However, for some soils containing between 5 and 15 % fines, the use of impact compaction (Test Methods D698 or D1557 ) may be useful in evaluating what is an appropriate maximum index density/unit weight. 1.7 These test methods will typically produce a lower maximum dry density/unit weight than that obtained by vibrating hammer using Test Method D7382 . 1.8 For many types of free-draining, cohesionless soils, these test methods cause a moderate amount of degradation (particle breakdown) of the soil. When degradation occurs, typically there is an increase in the maximum index density/unit weight obtained, and comparable test results may not be obtained when different size molds are used to test a given soil. 1.9 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.9.1 For purposes of comparing a measured or calculated value(s) to specified limits, the measured or calculated value(s) shall be rounded to the nearest decimal or significant digits in the specified limits. 1.9.2 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. 1.10 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. 1.11 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 For many cohesionless, free-draining soils, the maximum index density/unit weight is one of the key components in evaluating the state of compactness of a given soil mass that is either naturally occurring or placed during construction. 5.1.1 Relative density and percent compaction are commonly used for evaluating the state of compactness of a given soil mass. Density/unit weight index is also sometimes used. See Section 3 for descriptions of terms. 5.2 It is generally recognized that either relative density or percent compaction is a good indicator of the state of compactness of a given soil mass. However, the engineering properties, such as strength, compressibility, and permeability of a given soil, compacted by various methods to a given state of compactness can vary considerably. Therefore, considerable engineering judgment must be used in relating the engineering properties of soil to the state of compactness. 5.3 An absolute maximum density/unit weight is not necessarily obtained by these test methods. Note 2: In addition, there are published data to indicate that these test methods have a high degree of variability. 4 However, the variability can be greatly reduced by careful calibration of equipment, including the vibrating table, and careful attention to proper test procedure and technique. Note 3: 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 , generally, are 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 ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors. 5.4 The double amplitude of vertical vibration has been found to have a significant effect on the density obtained. 4 For a particular vibrating table and mold assembly, the maximum index density/unit weight of a given material may be obtained at a double amplitude of vibration other than the double amplitude of 0.013 ± 0.002 in. (0.33 ± 0.05 mm) at a frequency of 60 Hz or 0.019 ± 0.003 in. (0.48 ± 0.08 mm) at 50 Hz required in this method; that is, dry density/unit weight may initially increase with increasing double amplitude of vibration, reach a peak, and then decrease with further increases in double amplitude of vibration. Furthermore, the relationship between the peak density/unit weight and optimum double amplitude of vibration (double amplitude of vibration where peak density/unit weight occurrs) can vary with various soil types and gradations. 5.5 The use of the standard molds ( 6.1.1 ) has been found to be satisfactory for most soils requiring maximum index-density/unit weight testing. Special molds ( 6.1.2 ) shall only be used when the test results are to be applied in conjunction with design or special studies and there is not enough soil to use the standard molds. Such test results should be applied with caution as maximum index densities/unit weights obtained with the special molds may not agree with those that would be obtained using the standard molds.