1.1本试验方法包括通过伽马辐射衰减测定土壤和土石混合物的总密度或湿密度，其中源和探测器保持在表面上（背散射法），或源或探测器放置在300 mm（12 in.）以下的已知深度当探测器或光源留在表面时（直接传输法）。 1.2通过将γ辐射的检测率与之前建立的校准数据进行比较，确定受试材料的单位体积质量密度。 1.3以国际单位制测试值为标准。英寸-磅当量可能是近似值。 1.4工程专业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，使用记录磅质量（lbm）的天平或天平，或记录磅/立方英尺的密度，不应视为不符合本标准。 1.5 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和健康实践，并确定监管限制的适用性。 有关具体的危险说明，请参阅第6节。

1.1 This test method covers the determination of the total or wet density of soil and soil-rock mixtures by the attenuation of gamma radiation where the source and detector(s) remain on the surface (Backscatter Method) or the source or detector is placed at a known depth up to 300 mm (12 in.) while the detector(s) or source remains on the surface (Direct Transmission Method). 1.2 The density in mass per unit volume of the material under test is determined by comparing the detected rate of gamma radiation with previously established calibration data. 1.3 The values tested in SI units are to be regarded as the standard. The inch-pound equivalents may be approximate. 1.4 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, the use of balances or scales recording pounds of mass (lbm), or the recording of density in lbm/ft3 should not be regarded as nonconformance with this standard. 1.5 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific Hazard statements, see Section 6.