1.1 本试验方法包括通过机电手段测量土壤或土壤骨料混合物的原位刚度，以便根据某些假设确定杨氏模量。该仪器和程序提供了一种相当快速的测试手段，以尽量减少干扰和施工延迟。该测试程序旨在评估土方工程和道路工程中使用的材料的刚度或模量。快速原位刚度测试支持美国联邦和州根据模量规定建筑材料的原位性能。从该方法获得的结果适用于颗粒状无粘性材料的评估。它们也适用于20%以上的粉质和粘性材料的评估 % 不受含水量变化影响的细粒。如果粉质和粘性材料的含水量发生变化，则如果该方法的结果适用，则应考虑含水量。 用这种方法测量的刚度受边界条件的影响，特别是底层提供的支撑以及被测层的厚度和模量。由于该方法将被评估的层近似为半空间，因此测量的模量也是近似的。 1.2 刚度（单位位移的力）是通过向地面施加一个小的测量力，测量产生的表面速度并计算刚度来确定的。这是在一个频率范围内完成的，并对结果进行平均。 1.3 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。 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。 注1: 尽管本试验方法中包含精度和偏差声明；该测试方法的精度取决于执行该测试的人员的能力，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。本试验方法的使用者应注意遵守规程 D3740 本身不能保证可靠的测试。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。 1.5 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====== 4.1 所述装置和程序提供了一种测量土壤或土壤-骨料混合物层刚度的方法，从中可以确定假设泊松比的杨氏模量。低应变循环荷载由装置施加在与公路应用一致的静荷载周围 ( 1. ) . 4.2 该方法可用作监测或控制压实的非破坏性方法，以避免压实不足、过度压实或浪费精力。通过了解刚度与特定材料的密度、含水量和压实程序的关系，实现的刚度可以与基于密度的压实控制或规范相关的压实百分比有关，例如，以满足方法的要求 D698 使用标准工作或方法 D1557 使用修改后的作用力。 4.2.1 该方法适用于含20%以上的粉质和粘性材料 % 罚款。 在这种情况下，刚度和干密度或干容重之间的关系对含水量很敏感。应使用以下方法测定含水量:试验方法 D2216 , D4643 或 D4959 . 如果无法在刚度测量时立即进行测定，则应按照惯例保存和运输土壤样品 D4220 ，第8节，B、C或D组土壤。 4.2.2 该方法适用于道路基层或土方工程的施工，包括埋地管道的安装 ( 2. ) . 4.2.3 该方法的快速、非穿透性适合于生产测试，例如，它提供了一种不一定干扰或延迟施工的测试方法。 4.3 该方法适用于降低路面损坏的风险。通过确保公路底基层、路基和基层刚度的相对均匀性，路面上的应力分布更加均匀。 通过这种方式，延长了路面的使用寿命，并最大限度地减少了维修。 4.4 该方法适用于确定土壤或土壤骨料结构的表面何时能够支撑设计荷载。这对于材料随时间硬化（变硬）且密度或含水量没有可测量变化的稳定填料非常有用。 4.5 本试验方法适用于现场测定土壤和土壤骨料混合物的杨氏模量和剪切模量 ( 3. , 4. ) . 用这种方法测量的刚度与模量有关 ( 5. ) 根据泊松比假设和仪器底部半径，如下所示: 哪里: K gr公司 = 被测地面层的刚度，MN/m（klbf/in）， R = 仪器底座的外径，m（in）， ν = 泊松比， E = 杨氏模量，MPa（kpsi），和 G = 剪切模量，MPa（kpsi）。 4.5.1 粉质和粘性材料的刚度和模量将随含水量而变化，并可能导致- 压实坍塌、承载力损失或有效抗剪强度损失。此外，对于细粒含量显著的粉质和粘性材料，较高的刚度并不一定能确保充分压实 ( 6. ) .

1.1 This test method covers the measurement by electro-mechanical means of the in-place stiffness of soil or soil-aggregate mixtures so as to determine a Young's modulus based on certain assumptions. The apparatus and procedure provide a fairly rapid means of testing so as to minimize interference and delay of construction. The test procedure is intended for evaluating the stiffness or modulus of materials used in earthworks and roadworks. Rapid in-place stiffness testing supports U.S. federal and state efforts to specify the in-place performance of construction materials based on modulus. Results obtained from this method are applicable to the evaluation of granular cohesionless materials. They are also applicable to the evaluation of silty and clayey materials with more than 20 % fines that are not subject to a change in moisture content. If the silty and clayey material experiences a change in moisture content, then moisture content shall be taken into account if the results of this method are to be applicable. The stiffness measured with this method is influenced by boundary conditions, specifically the support offered by underlying layers as well as the thickness and modulus of the layer being tested. Since this method approximates the layer(s) being evaluated as a half-space, then the modulus measured is also approximate. 1.2 The stiffness, in force per unit displacement, is determined by imparting a small measured force to the surface of the ground, measuring the resulting surface velocity and calculating the stiffness. This is done over a frequency range and the results are averaged. 1.3 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. 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. Note 1: Notwithstanding the statements on precision and bias contained in this test method; the precision of 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 this test method are cautioned that compliance with Practice D3740 does not in itself assure reliable testing. Reliable testing depends on many factors; Practice D3740 provides a means of evaluating some of those factors. 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 ====== 4.1 The apparatus and procedure described provides a means for measurement of the stiffness of a layer of soil or soil-aggregate mixture from which a Young's modulus may be determined for an assumed Poisson's ratio. Low strain cyclic loading is applied by the apparatus about a static load that is consistent with highway applications ( 1 ) . 4.2 This method is useful as a non-destructive method for monitoring or controlling compaction so as to avoid under-compaction, over-compaction or wasted effort. Through an understanding of how stiffness relates to density for a particular material, moisture content and compaction procedure, the stiffness achieved can be related to % compaction in connection with density based compaction control or specifications, for example, to meet the requirements of Method D698 using standard effort or Method D1557 using modified effort. 4.2.1 This method applies to silty and clayey materials containing greater than 20 % fines. In such cases, the relationship between stiffness and dry density or dry unit weight is sensitive to the water content. Water contents should be determined by use of: Test Method D2216 , D4643 , or D4959 . If the determination cannot be made immediately at the time of the stiffness measurements, then soil samples shall be preserved and transported in accordance with Practice D4220 , Section 8, Groups B, C, or D soils. 4.2.2 This method is useful in the construction of road bases or earthworks, including the installation of buried pipe ( 2 ) . 4.2.3 The rapid, non-penetrating nature of this method is suited to production testing, for example, it provides a means of testing that does not necessarily interfere with or delay construction. 4.3 This method is suitable for mitigating the risk of pavement failure. By assuring the relative uniformity of highway subbase, subgrade and base stiffnesses, stresses on the pavement is more uniformly distributed. In this way the life of a pavement is extended and repairs minimized. 4.4 This method is suitable for determining when the surface of a soil or soil-aggregate structure is capable of supporting design loads. This is useful for stabilized fills where the material hardens (stiffens) over time without measurable changes in density or moisture content. 4.5 This test method is suitable for the in-place determination of a Young's and a shear modulus of soil and soil-aggregate mixtures ( 3 , 4 ) . Stiffness, as measured by this method, is related to modulus ( 5 ) from an assumption of Poisson's ratio and from the radius of the foot of the apparatus as follows: where: K gr = stiffness of the ground layer being measured, MN/m (klbf/in.), R = outside radius of the apparatus' foot, m (in.), ν = Poisson's ratio, E = Young's modulus, MPa (kpsi), and G = Shear modulus, MPa (kpsi). 4.5.1 The stiffness and modulus of silty and clayey materials will change with moisture content and can possibly result in hydro-compaction collapse, loss of bearing capacity or loss of effective shear strength. In addition, for silty and clayey materials with significant fines content, higher stiffness does not necessarily assure adequate compaction ( 6 ) .