1.1 本试验方法描述了快速确定压实度和现场土壤最佳含水量变化的程序，用于控制压实土的施工。这些值是在不知道含水量值的情况下，在与原地土壤相同的含水量下绘制三点压实曲线获得的。用于压实曲线的土壤通常与现场密度测试中移除的土壤相同。对于本名称的其余部分，本试验方法将被称为 快速法 . 1.2 该试验方法通常适用于含15%以上的土壤 % 细颗粒（筛径为-75µm（200号））。 1.3 当被测土壤中存在砾石大小的颗粒时，该试验方法仅限于-4的比较。 现场密度材料的75 mm（4号）筛孔分数，以进行-4.75 mm（4号）筛孔材料的实验室压实试验（试验方法a D698 ). 受实践限制 D4718/D4718M ，该试验方法也适用于其他筛分粒级的比较（例如，试验方法的方法C D698 )或其他压实工作（例如，试验方法 D1557 )如果确定了新的含水量调整值（参见 6.1 和 附录X2 ). 1.4 单位- 以国际单位制表示的数值应视为标准值。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。 1.4.1 使用天平或天平记录质量磅（lbm），或记录密度磅/立方英尺（lbm/ft） 3. )不应视为不符合本试验方法。 1.4.2 根据规范，使用“标准”系统识别筛网名称 E11 例如25毫米和75微米，然后是1英寸的“替代”系统。括号中分别为第200号和第200号。 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 除非被本标准取代。 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。 参见第节 9 . 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 快速方法用于快速评估施工中使用的土壤的压实百分比和最佳含水量变化，而不知道测试时的现场含水量值。 5.1.1 测试结果通常在测试开始后1到2小时内确定。 5.1.2 使用快速方法获得的压实度值将与使用干密度值计算的压实度值相同。 5.1.3 田间含水量和最佳含水量之间的差值将是近似值，但将在已知田间含水量后计算的差值的±0.1至0.2个百分点范围内。 5.2 试验结果可用于确定压实材料是否符合密度和含水量控制值，该值以标准最大密度和最佳含水量的百分比表示，如在试验方法的方法a中确定的 D698 . 使用三点压实曲线代替试验方法中要求的四点或五点曲线 D698 . 5.3 该试验方法基于以下假设:三点压实曲线是接近最佳含水量的曲线截面处的抛物线，因此可以通过数学方法确定曲线的峰值。 这种假设导致了该试验方法与从完整的五点压实曲线中获得最大密度和最佳含水量之间的主要差异。 5.4 根据试验方法确定现场干燥含水量后 D2216 ，可以计算干密度、干容重和最佳含水量的值（参见 注1 ). 5.5 该试验方法也可用于基础或取土区材料，以比较现场干密度、单位重量和含水量与实验室最大干密度、单位重量和最佳含水量。 5.6 该试验方法的优点是，在现场密度试验期间，可以在开挖的同一土壤上获得最大密度值。 注1: 由于无需立即从中确定材料的含水量- 放置密度测试或实验室压实点，不需要使用快速水分测定，如微波、直接加热、核能等。然而，如果需要，可使用基于快速含水量测试方法的干密度值确定压实百分比和最佳含水量的变化。使用三个压实点并通过数学方法确定最大密度仍然适用。然而，快速含水量法可能会得出与公认的烘干含水量值不同的结果，并会延长执行该试验方法的时间。 注2: 本试验方法产生的结果质量取决于执行该试验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测试。这些试验方法的使用者应注意遵守规程 D3740 本身不能确保可靠的结果。可靠的测试取决于许多因素；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 procedure for rapidly determining the percent compaction and the variation from optimum water content of an in-place soil for use in controlling construction of compacted earth. These values are obtained by developing a three-point compaction curve at the same water content as the in-place soil without knowing the value of the water content. The soil used for the compaction curve is normally the same soil removed from the in-place density test. For the remainder of this designation, this test method will be referred to as the rapid method . 1.2 This test method is normally performed for soils containing more than 15 % fines (minus 75-µm (No. 200) sieve size). 1.3 When gravel-size particles are present in the soil being tested, this test method is limited to a comparison of the minus 4.75-mm (No. 4) sieve-size fraction of the in-place density material to a laboratory compaction test of minus 4.75-mm (No. 4) sieve-size material (Method A of Test Methods D698 ). Subject to the limitations of Practice D4718/D4718M , this test method is also applicable to comparisons of other sieve-size fractions (for example, Method C of Test Methods D698 ) or other compactive efforts (for example, Test Methods D1557 ) if new water content adjustment values are determined (see 6.1 and Appendix X2 ). 1.4 Units— The values stated in SI units are to be regarded as standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 1.4.1 The use of balances or scales recording pounds of mass (lbm), or the recording of density in pounds of mass per cubic foot (lbm/ft 3 ) should not be regarded as nonconformance with this test method. 1.4.2 The sieve designations are identified using the “standard” system in accordance with Specification E11 , such as 25-mm and 75-μm, followed by the “alternative” system of 1-in. and No. 200, respectively, in parentheses. 1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 unless superseded by this standard. 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 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; 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 analytical 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. See Section 9 . 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 rapid method is performed to quickly evaluate percent compaction and variation from optimum water content of soils used in construction without knowing the value of field water content at the time of the test. 5.1.1 Test results are usually determined within 1 to 2 h from the start of the test. 5.1.2 The value of percent compaction obtained using the rapid method will be the same as the percent compaction calculated using dry density values. 5.1.3 The value of the difference between field water content and optimum water content will be approximate, but will be within ±0.1 to 0.2 percentage point of the difference calculated once the field water content is known. 5.2 Test results may be used to determine if the compacted material meets density and water content control values that are specified as a percentage of a standard maximum density and optimum water content such as determined in Method A of Test Methods D698 . A three-point compaction curve is used in place of the four- or five-point curve required in Test Methods D698 . 5.3 This test method is based on the assumption that a three-point compaction curve is a parabola at the section of the curve close to optimum water content so that the peak point of the curve can be determined mathematically. This assumption results in the major difference between this test method and obtaining the maximum density and optimum water content from a full five-point compaction curve. 5.4 Once the field ovendry water content has been determined in accordance with Test Methods D2216 , the values of dry density, dry unit weight, and optimum water content can be calculated (see Note 1 ). 5.5 This test method can also be used for foundation or borrow area material to compare in-place dry density and unit weight and water content to laboratory maximum dry density and unit weight and optimum water content. 5.6 This test method has the advantage that the maximum density value can be obtained on the same soil excavated during the in-place density test. Note 1: Since there is no need to immediately determine the water contents of material from the in-place density test or the laboratory compaction points, use of rapid water content determinations such as microwave, direct heat, nuclear, etc., is not needed. However, if desired, the percent compaction and variation from optimum water content may be determined using dry density values based on rapid water content test methods. Using three compaction points and determining the maximum density mathematically would still apply. However, the rapid water content methods may give results that differ from the accepted oven-dried water content values and will lengthen the time of performing this test method. Note 2: The quality of the results produced by this test method 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. Users of these test methods are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable testing depends on many factors; Practice D3740 provides a means of evaluating some of those factors.