1.1 本试验方法涵盖了确定岩石点荷载强度指数的指南、要求和程序。这是一种指数测试，旨在用于分类岩石强度。 1.2 采用本试验方法可对直径为30至85 mm的岩芯、块体或不规则块状试样进行试验。 1.3 该试验方法可在现场或实验室进行。试验通常用于现场，因为试验机是便携式的，只需要很少或最少的样本制备，样本可以在采集后的短时间内进行测试。 1.4 本试验方法适用于中等强度岩石（抗压强度超过15 MPa）。 1.5 本试验方法不包括应测试哪种类型的试样，也不包括是否应考虑各向异性因素。在测试之前，甚至可能在采样之前，需要制定点负载测试程序的细节。这些细节将取决于数据的预期用途，以及可能的预算约束和可能的其他因素，这些因素不在本测试方法的范围内。 1.6 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 . 1.6.1 本标准中用于规定如何收集/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 1.7 以国际单位制表示的数值应视为标准值。 1.8 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。 ====意义和用途====== 5.1 单轴压缩试验（见试验方法 D7012 )用于确定岩石样本的抗压强度。然而，这是一项耗时且昂贵的测试，需要大量的样本制备，并且在采集样本后很长时间内可能无法获得结果。当需要大量的测试和/或及时的信息来获取初步和勘测信息时，可以使用替代测试，如点荷载测试，以减少抗压强度测试的时间和成本。这些数据可用于在勘探阶段作出及时和更明智的决定，以及更有效和成本效益更高的样本选择，以进行更精确和更昂贵的实验室测试。 5.2 点荷载强度试验用作岩石材料强度分类的指标试验。试验结果不得用于设计或分析目的。 5.3 本试验方法用于确定岩石样本的点荷载强度指数，以及（如需要）点荷载强度各向异性指数。 5.4 岩芯（径向和轴向测试）、切割块（块体测试）或不规则块（不规则块体测试）形式的岩石样本通过一对截短的锥形板施加集中荷载进行测试。几乎不需要或不需要制备样本，因此可以在获得样本后不久进行测试，并将水分条件对测试数据的任何影响降至最低。 然而，从获得样本到测试样本的处理方式会对结果产生很大影响。因此，可能有必要按照惯例处理样本 D5079 并在数据收集中以某种方式记录水分条件。 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 通常认为能够胜任客观的测试和采样。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 This test method covers the guidelines, requirements, and procedures for determining the point load strength index of rock. This is an index test and is intended to be used to classify rock strength. 1.2 Specimens in the form of rock cores, blocks, or irregular lumps with a test diameter from 30 to 85 mm can be tested by this test method. 1.3 This test method can be performed in either the field or laboratory. The test is typically used in the field because the testing machine is portable, little or minimal specimen preparation is required, and specimens can be tested within a short time frame of being collected. 1.4 This test method applies to medium strength rock (compressive strength over 15 MPa). 1.5 This test method does not cover which type of specimen should be tested or whether anisotropic factors should be considered. The specifics of the point load test program need to be developed prior to testing and possibly even before sampling. Such specifics would be dependent on the intended use of the data, as well as possible budgetary constraints and possible other factors, which are outside the scope of this test method. 1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.6.1 The procedures used to specify how data are collected/recorded and 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 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 commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering design 1.7 The values stated in the SI units are to be regarded as standard. 1.8 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. ====== Significance And Use ====== 5.1 The uniaxial compression test (see Test Method D7012 ) is used to determine compressive strength of rock specimens. However, it is a time-consuming and expensive test that requires significant specimen preparation and the results may not be available for a long time after the samples are collected. When extensive testing and/or timely information is needed for preliminary and reconnaissance information, alternative tests such as the point load test can be used to reduce the time and cost of compressive strength tests, when used in the field. Such data can be used to make timely and more informed decisions during the exploration phases and more efficient and cost effective selection of samples for more precise and expensive laboratory tests. 5.2 The point load strength test is used as an index test for strength classification of rock materials. The test results should not be used for design or analytical purposes. 5.3 This test method is performed to determine the point load strength index of rock specimens and, if required, the point load strength anisotropy index. 5.4 Rock specimens in the form of either core (the diametral and axial tests), cut blocks (the block test), or irregular lumps (the irregular lump test) are tested by application of concentrated load through a pair of truncated, conical platens. Little or no specimen preparation is needed and can therefore be tested shortly after being obtained and any influence of moisture condition on the test data minimized. However, the results can be highly influenced by how the specimen is treated from the time it is obtained until the time it is tested. Therefore, it may be necessary to handle specimens in accordance with Practice D5079 and to document moisture conditions in some manner in the data collection. Note 1: The quality of the result produced by this standard is dependent upon 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 and sampling. 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.