1.1 这些测试方法涉及在几乎垂直的平面上向下传播的压缩波（P）和剪切波（S）。地震波可以表示为P 五、 或P Z 对于向下传播的压缩波和 VH 或S ZX公司 对于向下传播和水平极化的剪切波。S VH 或S ZX公司 也称为S H 波动这些测试方法仅限于根据压缩（P）波和垂直（SV）和水平（SH）方向的剪切（S）地震波的到达时间和相对到达时间确定层速度，这些地震波在地表附近产生，并向下传播到垂直安装的地震传感器阵列。讨论了两种方法，包括使用一个或两个井下传感器（接收器）。 1.2 将讨论数据的各种应用，并讨论可接受的程序和设备，如震源、接收器和记录系统。 讨论的其他项目包括震源与接收器间距、钻孔、套管、灌浆、钻孔安装程序以及进行实际钻孔和地震锥测试。数据简化和解释仅限于识别各种地震波类型、视速度与真实速度的关系、示例计算、使用斯奈尔折射定律和假设。 1.3 有几种可接受的设备可用于生成高质量的P或SV源波或两者和SH源波。几种商用接收器和记录系统也可用于进行可接受的井下测量。应特别考虑使用的接收器类型及其配置，以提供准确反映输入运动的输出。这些测试方法主要涉及实际测试程序、数据解释和设备规范，以产生统一的测试结果。 1.4 所有记录和计算值应符合实践中制定的有效数字和舍入指南 D6026 . 1.4.1 用于指定如何在这些试验方法中收集/记录和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这些测试方法的范围。 1.4.2 比这些试验方法中规定的更有效数字或更高灵敏度的测量不应视为不符合本标准。 1.5 单位- 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.5.1 在处理英寸磅单位时，使用英寸磅单位的重力系统。在这个系统中，磅（lbf）表示力（重量）的单位，而质量的单位是段塞。未给出合理化的缓动单元，除非动态（F = ma）涉及计算。 1.5.2 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。如前所述，本标准包括英寸-磅单位的重力系统，不使用/呈现质量的段塞单位。然而，使用天平或天平记录磅质量（lbm）或记录密度（lbm/ft） 3. 不应视为不符合本标准。 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。 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 地震井下方法为设计者提供了与所讨论材料的地震波速相关的信息 ( 1. ) 3. . 纵波和横波速度与泊松比、剪切模量、体积模量和杨氏模量等重要岩土弹性常数直接相关。准确的现场纵波和横波速度剖面在岩土地基设计中至关重要。这些参数用于静态和动态荷载下的土壤行为分析，其中弹性常数是定义不同变形状态（如弹性、弹塑性和破坏）的模型的输入变量。估计剪切波速在岩土工程设计中的另一个重要用途是土壤液化评估。 5.2 测试方法固有的一个基本假设是，正在表征横向均匀介质。 在横向均匀介质中，源波列轨迹遵循斯奈尔折射定律。测试方法固有的另一个假设是，待表征的地层介质可能具有横向各向同性。横向各向同性是各向异性的一种特别简单的形式，因为速度仅随垂直入射角而变化，而不随方位角而变化。通过在平面图中旋转90°的偏移处放置和驱动震源，可以确认需要更复杂的模型来评估现场数据。 5.3 在饱和软土中，土壤的P波速小于水的P波速，约为1450 m/s[4750 ft/s]，P波速测量主要由水的P波速控制，不可能直接测量土壤P波速。 注1: 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 These test methods address compression (P) and shear (S) waves propagating in the downward direction in a nearly vertical plane. The seismic waves can be denoted as P V or P Z for a downward propagating compression wave and as S VH or S ZX for downward propagating and horizontally polarized shear wave. The S VH or S ZX is also referred to as an S H wave. These test methods are limited to the determination of the interval velocities from arrival times and relative arrival times of compression (P) waves and vertically (SV) and horizontally (SH) oriented shear (S) seismic waves which are generated near surface and travel down to an array of vertically installed seismic sensors. Two methods are discussed, which include using either one or two downhole sensors (receivers). 1.2 Various applications of the data will be addressed and acceptable procedures and equipment, such as seismic sources, receivers, and recording systems will be discussed. Other items addressed include source-to-receiver spacing, drilling, casing, grouting, a procedure for borehole installation, and conducting actual borehole and seismic cone tests. Data reduction and interpretation is limited to the identification of various seismic wave types, apparent velocity relation to true velocity, example computations, use of Snell's law of refraction, and assumptions. 1.3 There are several acceptable devices that can be used to generate a high-quality P or SV source wave or both and SH source waves. Several types of commercially available receivers and recording systems can also be used to conduct an acceptable downhole survey. Special consideration should be given to the types of receivers used and their configuration to provide an output that accurately reflects the input motion. These test methods primarily concern the actual test procedure, data interpretation, and specifications for equipment which will yield uniform test results. 1.4 All recorded and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026 . 1.4.1 The procedures used to specify how data are collected/recorded and calculated in these test methods are regarded as the industry standard. In addition, they are representative of the significant digits that should generally 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 these test methods to consider significant digits used in analysis methods for engineering design. 1.4.2 Measurements made to more significant digits or better sensitivity than specified in these test methods shall not be regarded a nonconformance with this standard. 1.5 Units— The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The rationalized slug unit is not given, unless dynamic (F = ma) calculations are involved. 1.5.2 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 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. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit for mass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft 3 shall not be regarded as nonconformance with this standard. 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. 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 seismic downhole method provides a designer with information pertinent to the seismic wave velocities of the materials in question ( 1 ) 3 . The P-wave and S-wave velocities are directly related to the important geotechnical elastic constants of Poisson’s ratio, shear modulus, bulk modulus, and Young’s modulus. Accurate in-situ P-wave and S-wave velocity profiles are essential in geotechnical foundation designs. These parameters are used in both analyses of soil behavior under both static and dynamic loads where the elastic constants are input variables into the models defining the different states of deformations such as elastic, elasto-plastic, and failure. Another important use of estimated shear wave velocities in geotechnical design is in the liquefaction assessment of soils. 5.2 A fundamental assumption inherent in the test methods is that a laterally homogeneous medium is being characterized. In a laterally homogeneous medium the source wave train trajectories adhere to Snell’s law of refraction. Another assumption inherent in the test methods is that the stratigraphic medium to be characterized can have transverse isotropy. Transverse isotropy is a particularly simple form of anisotropy because velocities only vary with vertical incidence angle and not with azimuth. By placing and actuating the seismic source at offsets rotated 90° in plan view, it may be possible to confirm that a more complex model is needed to evaluate the field data. 5.3 In soft saturated soil, where the P-wave velocity of the soil is less than the P-wave velocity of water, which is about 1450 m/s [4750 ft/s], the P-wave velocity measurement will primarily be controlled by the P-wave velocity of water and a direct measurement of the soil P-wave velocity will not be possible. Note 1: The quality of the results produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities. 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 many factors; Practice D3740 provides a means of evaluating some of those factors.