1.1 本试验方法提供了将试验方法获得的标准渗透试验（SPT）N值归一化的程序 D1586/D1586M 用于估算砂的工程性质的标准能量。为了减少SPT的固有可变性，这种测试方法需要能量测量并限制锤系统和钻孔方法。参考标准测试方法 D1586/D1586M 关于土壤的渗透试验（SPT）和分桶取样，本标准中引用的详细信息。标准指南 D6286/D6286M 提供有关钻孔方法的附加信息。 1.2 该试验方法要求使用自动锤，并使用试验方法测定能量传递EFV D4633 校正SPT N值并将其归一化为N 60 在60%ETR时（见 3.3 ). 1.3 该标准的前一版本是专门为砂的液化评估而制定的，以提供SPT（N 1 ) 60 标准化为一个大气压的覆盖层应力的值。抗液化性的评价需要合格的专业判断，并且（N 1 ) 60 更正现载于 附录X1 圆锥贯入试验（试验方法 D5778 ）也用于液化评估，因为它经济并提供详细的地层数据。 1.4 单位- 以英寸-磅单位或国际单位制单位表示的值应单独视为标准值。每个系统中陈述的值可能不完全等同；因此，每个系统应独立使用。合并两个系统的值可能导致不符合标准。以英寸-磅单位以外的单位报告测试结果不应被视为不符合本惯例。本文所示的SI等效单位通常符合现有的国际标准。 1.4.1 覆盖层应力压力修正计算方法 附录X1 ，常用单位为吨/英尺 2 ,千克/厘米 2 、自动取款机和酒吧。由于这些单位大致相等（在1.1倍以内），许多用户更喜欢在应力校正计算中使用这些单位。对于使用kPa或kN/m的 2 ，100 kPa约等于一吨/英尺 2 对于这些单元，应力指数n近似相等。 1.5 所有观察值和计算值应符合实践中制定的有效数字和四舍五入指南 D6026 . 1.6 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 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》中确立的国际公认的标准化原则制定的。 ======意义和用途====== 5.1 该标准用于获得比使用测试方法获得的SPT N值更可靠的SPT N值 D1586/D1586M ，这允许设备、校准要求和锤子操作的更大可变性。本文描述的方法需要自动锤或脱扣锤、能量测量和钻孔质量检查，并且它限制了钻井方法以确保更可重复的N-价值观。不允许绳索和猫头锤操作。当N值用于岩土设计目的时，应规定该试验方法。 5.2 SPT N值用于估计土壤强度和压缩性的工程特性。该测试在难以回收完整样品进行实验室测试的沙子中更有用。SPT可用于粘土，但在软粘土中不可靠。可靠的设计要求N值调整为60%的钻杆ETR，N 60 由于锤系统的广泛可变性。60%的ETR代表了用于开发许多土壤性质相关性的平均ETR。砂土液化评估的设计需要进一步将N值归一化为参考应力水平（见 附录X1 ). 5.2.1 SPT用于地下水位以上和以下的从沙子到粘土的各种土壤中（参见4。3 D1586/D1586M ），但一般不适用于导致拒绝的砾石和胶结或部分锂化的土壤。这种测试方法需要使用流体来钻探地下水位以下的松散砂，因为它们变得不稳定。该试验可应用于非饱和土壤，其他钻井方法具有稳定的钻孔和免除流体钻井要求。当将SPT应用于非饱和土壤时，如果土壤在钻孔过程中或施工后变得饱和，用户必须考虑特性的任何变化。 5.3 该测试方法要求使用测试方法测量钻杆能量EFV和确定能量传递比ETR D4633 该测量是通过在表面处的冲击砧正下方测量钻杆来进行的。根据项目要求，通过改变锤下落高度，可以将锤系统调整到任何期望的ETR。例如，许多自动锤以50 BPM（每分钟打击）的快速速度运行并提供高能量。速度可以降低，以允许详细记录渗透率或满足其他项目要求。 5.3.1 连续测量EFV可能不切实际，在这种情况下，锤系统要么在关键项目的现场定期测量，要么定期测量（见 10.2 ).一旦了解了特定锤子的ETR，就可以通过监控打击计数率和锤子冲击速度来检查锤子的性能，以验证它们是否一致运行。 5.4 使用这种做法提供了一个扰动土壤样品，用于鉴定和实验室测试，如含水量（测试方法 D2216 ）和土壤分类（试验方法 D2487 , D2488 ).分类信息通常用于开发场地地层学。附注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。符合执业准则的机构 D3740 通常被认为能够胜任和客观的测试/取样/检查。可靠的结果取决于许多因素；实践 D3740 提供了一种评估部分（但不是全部）这些因素的方法。 实践 D3740 是为从事土壤和岩石实验室测试、检查或两者兼而有之的机构开发的。因此，它并不完全适用于执行该现场测试的机构。这种测试方法的使用者应该认识到实践的框架 D3740 适用于评价执行本试验方法的机构的质量。目前，没有已知的合格的国家机构来检查执行这种测试方法的机构。

1.1 This test method provides a procedure to normalize the Standard Penetration Test (SPT) N-value obtained from Test Method D1586/D1586M to standard energy for estimating engineering properties of sands. To reduce the inherent variability of the SPT, this test method requires energy measurements and restricts hammer systems and drilling methods. Refer to Standard Test Method D1586/D1586M on Penetration Test (SPT) and Split-Barrel Sampling of Soils for detailed information cited throughout this standard. Standard Guide D6286/D6286M provides additional information on drilling methods. 1.2 This test method requires the use of automatic hammers and the determination of the energy transmission, EFV, using Test Method D4633 to correct the SPT N-value and normalize it to N 60 at 60 percent ETR (see 3.3 ). 1.3 The previous version of this standard was developed specifically for liquefaction evaluation of sands to provide an SPT (N 1 ) 60 value normalized to overburden stress of one-atmosphere pressure. Evaluation of liquefaction resistance requires qualified professional judgment, and (N 1 ) 60 corrections are now given in Appendix X1 . Cone Penetration Testing (Test Method D5778 ) is also used for liquefaction evaluations as it is economical and provides detailed stratigraphic data. 1.4 Units— The values stated in either inch-pound units or SI 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. Reporting of test results in units other than inch-pound units shall not be regarded as nonconformance with this practice. SI equivalent units shown herein are in general conformance with existing international standards. 1.4.1 For overburden stress pressure correction calculations methods in Appendix X1 , common units are ton/ft 2 , kg/cm 2 , atm, and bars. Since these units are approximately equal (within a factor of 1.1), many users prefer the use of these units in stress correction calculations. For those using kPa or kN/m 2 , 100 kPa is approximately equal to one ton/ft 2 . The stress exponent, n, is approximately equal for these units. 1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 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 This standard is used to obtain more reliable SPT N-values than those that can be obtained using Test Method D1586/D1586M , which allows greater variability in equipment, calibration requirements, and hammer operation. The method described herein requires automatic or trip hammers, energy measurements, and borehole quality checks, and it restricts drilling methods to assure more repeatable N-values. Rope and cathead hammer operation is not allowed. This test method should be specified when N Values are used for geotechnical design purposes. 5.2 SPT N-values are used to estimate engineering properties of strength and compressibility of soils. The test is more useful in sands where recovery of intact samples for laboratory testing is difficult. SPT can be used in clays but is unreliable in soft clays. Reliable design requires N-values adjusted to a 60 % drill rod ETR, N 60 , due to the wide variability of hammer systems. An ETR of 60 % is representative of the average ETR used to develop many soil property correlations. Design for sand liquefaction evaluation requires further normalization of N-values to a reference stress level (see Appendix X1 ). 5.2.1 SPT is used in a wide variety of soils from sand to clays both above and below the water table (refer to 4.3 D1586/D1586M ) but is generally not applicable to gravels and cemented or partially lithified soils that result in refusal. This test method requires use of fluids for drilling of loose sands below water table as they become unstable. This test can be applied to unsaturated soils with other drilling methods that have a stable borehole and fluid drilling requirements waived. When applying SPT to unsaturated soil the user must consider any changes to properties if the soil becomes saturated during drilling or after construction. 5.3 This test method requires measurement of the drill rod energy, EFV, and determination of the energy transfer ratio, ETR, using Test Method D4633 . This measurement is performed by instrumenting drill rods just below the impact anvil at the surface. A hammer system may be adjusted to any desired ETR depending on project requirements by changing hammer drop height. For example, many automatic hammers run at fast rates of 50 BPM (blows per minute) and deliver high energy. The speed may be reduced to allow for detailed recording penetration rates or to meet other project requirements. 5.3.1 It may not be practical to measure EFV continuously, in which case hammer systems are measured periodically either onsite at critical projects or on a regular schedule (see 10.2 ). Once ETR is known for a specific hammer, it is possible to check hammer performance by monitoring blow count rates and hammer impact velocities to verify they are operating consistently. 5.4 Use of this practice provides a disturbed soil sample for identification and for laboratory testing such as water content (Test Method D2216 ) and Soil Classification (Test Methods D2487 , D2488 ). The classification information is commonly used to develop site stratigraphy. Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the equipment and facility used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some, but not all, of those factors. Practice D3740 was developed for agencies engaged in laboratory testing, inspection, or both, of soils and rock. As such, it is not totally applicable to agencies performing this field test. Users of this test method should recognize that the framework of Practice D3740 is appropriate for evaluating the quality of an agency performing this test method. Currently, there is no known qualifying national authority that inspects agencies that perform this test method.