1.1 本试验方法确立了使用N尺寸、75.7 mm（2.98 in.）的柔性体积膨胀仪测定岩体原位变形模量和其他辅助数据的指南、要求、程序和分析钻孔( 图1 和 图2 ). 本标准未详细介绍循环、蠕变和卸载循环，但可在将来添加，或与单独的测试标准、实践或指南一起添加。 图1 在钻孔中放气（a）和充气（b）的柔性膨胀计的概述 图2 未充气（r=0）起始位置下膨胀计的钻孔和可膨胀膜部分的横截面 注1: 其他岩体变形性试验包括径向千斤顶试验、平板千斤顶试验、柔性板试验和钻孔千斤顶试验。 1.2 本试验方法主要适用于N尺寸（75.7-mm（2.98-in.）的商用柔性体积膨胀计一、 D.）在钻孔中液压充气和放气的钻孔。然而，该试验方法可适用于其他膨胀计，包括气动膨胀计，或适用于不同的钻孔尺寸，以及英国标准协会EN ISO 22476- 5 (https://geotechnicaldesign.info). 使用不同直径或类型的体积膨胀计由业主或项目经理决定，不得视为不符合本标准。 1.3 目的、应用、使用范围和限制: 1.3.1 该名称是在获取岩石上或岩石中结构的设计、施工或维护数据的背景下描述的。该方法可以在任何方向上进行，但通常根据设计考虑在垂直或水平钻孔中进行。 1.3.2 除测试设备、钻孔质量、测试人员以及钻孔和定位测试组件的设备的限制外，测试没有深度限制。 1.3.3 由于这是一项体积测试，因此只能获得钻孔周围的平均变形。如果由于任何原因，包括地应力场或裂缝密度，岩石特性具有明显的各向异性，则该设备无法检测到这种差异。 1.3.4 由于过大的钻孔、风化、岩性或不连续性，测试区内的探头可能会发生大膨胀。 因此，膨胀计的最大压力和膨胀将受到限制。例如，对于一个特定的膨胀计，为了避免损坏优选N尺寸的膜，75.7 mm（2.98 in.）一、 D.钻孔，最大工作压力为30000 kPa（4350 lbf/in。 2. )也许有可能。相反，在82.5毫米（3.25英寸）处，最大工作压力将降至20680 kPa（3000 lbf/in）。 2. ). 此外，无论是超大钻孔还是低模量测试间隔，最大直径（充气）仅为85。 5毫米（3.37英寸）是允许的。 1.3.5 加压期间井壁的径向位移由膨胀计的总体积变化计算得出。因此，体积膨胀仪的测试结果仅表明变形模量的平均值。 1.3.6 体积膨胀仪测试无法提供岩体的各向异性特性，因为它测量的是平均变形，而不是特定方向的变形。然而，通过在不同方向的钻孔中进行膨胀计测试，或在已形成水力型裂缝的任何测试层段中获取压痕封隔器数据，可以获得现场各向异性条件的某些方面。 1.4 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。以国际单位制以外的单位报告试验结果不应视为不符合本标准。 1.4.1 在处理英寸磅单位时，使用英寸磅单位的重力系统。在该系统中，磅（lbf）表示力（重量）的单位，而质量的单位是段塞。除非涉及动态（F=ma）计算，否则未给出缓动单元。 1.5 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 . 1.5.1 用于指定如何在标准中收集/记录或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本标准的范围。 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 膨胀计测试通常在垂直钻孔中进行。它可以用于倾斜或水平钻孔，但探头会沿井壁拖动。 5. 2. 获得了岩石的变形模量、蠕变特性、回弹和永久变形数据，对工程设计有用。 5.3 岩体不连续性、地应力、地质历史、结晶学、纹理、组构和其他因素将决定岩体特性，而仅实验室尺寸测试可能无法测量，而膨胀计测试可能更能够测量。 5.4 岩体可变形性的确定是大坝基础设计、地下开挖支护、桥墩、沉箱和岩石边坡稳定性的关键参数。 注2: 尽管岩体表现为各向异性和不均匀性，但岩体变形模量的计算基于弹性和均匀性假设。然而，它们仍然呈现出实用、简单、可用的结果，并且与使用不均匀性和非弹性获得的结果没有显著差异。 注3: 现有的地应力只能通过岩体的原位测试来估算，例如本次测试或其他测试。 5.5 像这样的原位测试提供了有关岩体行为的一般信息。 在设计和建造特定结构时，建议进行膨胀计测试。 5.6 膨胀计测试可以以合理的成本和努力进行。与其他变形性测试（如径向千斤顶或柔性板测试）相比，膨胀计测试也更便宜和耗时，这些测试也需要地下挖掘和通道。 5.7 膨胀计模量可以与通过其他方法（例如，平板加载或径向顶升方法）获得的模量相关。然后，可以使用相关的膨胀计模量代替其他更昂贵的原位模量测试。 5.8 在进行大规模变形性测试（如径向千斤顶测试）之前，膨胀计测试可以提供岩体变形性的定性评估。 5.9 膨胀计对于节理岩石中钻孔的快速指数测井很有价值，因为节理岩石的岩芯回收率较差，且实验室测试的样本不足。 5.10 本标准中可膨胀膜的加压和降压是独特的。这是由表面手动泵驱动的双作用活塞直接在可膨胀膜上游完成的。 这种配置允许在相当深的深度使用膨胀计，消除油管和泵送系统的寄生膨胀，并迫使膜完全塌陷，无论钻孔柱是否有流体。 5.11 膨胀计测试结果可用于通过变形分析检查岩石上扩展基础的正常使用极限状态。 5.12 进行变形分析时，杨氏模量， E ，可以等于 E d 假设岩石具有线性弹性和各向同性。 注4: 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 This test method establishes the guidelines, requirements, procedure, and analyses for determining the in situ deformation modulus of a rock mass and other ancillary data using a flexible volumetric dilatometer in an N-size, 75.7 mm (2.98 in.) drill hole ( Fig. 1 and Fig. 2 ). Cyclic, creep, and unloading cycles are not covered in detail in this standard but may be added in the future or with a separate test standard, practice, or guide. FIG. 1 General Depiction of a Flexible Dilatometer, Deflated (a) and Inflated (b) in a Borehole FIG. 2 Cross-Sections of the Borehole and Dilatable Membrane Portion of the Dilatometer in the Uninflated, r = 0, Starting Position Note 1: Other rock mass deformability tests are radial jack tests, flat jack tests, flexible plate tests, and borehole jack tests. 1.2 This test method applies mainly to a commercially available flexible, volumetric dilatometer for an N-size, (75.7-mm (2.98-in.) I.D.) borehole that is inflated and deflated hydraulically in the borehole. However, the test method could apply to other dilatometers, including pneumatically inflated, or for different borehole sizes as well as covered under the British Standards Institute EN ISO 22476-5 (https://geotechnicaldesign.info). Use of a different diameter or type of volumetric dilatometer is up to the owner or project manager and shall not be regarded as nonconformance with this standard. 1.3 Purpose, Application, Range of Uses, and Limitations: 1.3.1 This designation is described in the context of obtaining data for the design, construction, or maintenance of structures on or in rock. This method can be conducted in any orientation but is usually conducted in a vertical or horizontal borehole as dictated by the design consideration. 1.3.2 The test has no depth limits other than those imposed by the limitations of the test equipment, drill hole quality, testing personnel, and equipment to drill the holes and position the testing assembly. 1.3.3 Since this is a volumetric test, only the average deformation is obtained around the borehole. If the rock properties, for any reason, including the in situ stress field or fracture density, are significantly anisotropic, then this device cannot detect that difference. 1.3.4 A large expansion of the probe in a test zone can occur due to either an oversized drill hole, weathering, lithology, or discontinuities. As a result, the maximum pressure and expansion of the dilatometer would be limited. For example, for one particular dilatometer to avoid damaging the membrane in a preferred N-size, 75.7 mm (2.98 in.) I.D., borehole, the maximum working pressure of 30,000 kPa (4,350 lbf/in. 2 ) might be possible. In contrast, at 82.5 mm (3.25 in.), the maximum working pressure would drop to only 20,680 kPa (3000 lbf/in. 2 ). Furthermore, regardless of if it an oversized drill hole or a low modulus test interval, the maximum diameter (inflated) of only 85.5 mm (3.37 in.) is allowed. 1.3.5 The radial displacements of the borehole walls during pressurization are calculated from the total volume change of the dilatometer. As such, the test results from a volumetric dilatometer indicates only the averaged value of the modulus of deformation. 1.3.6 The volumetric dilatometer test does not provide the anisotropic properties of the rock mass because it measures the average deformation and not the deformation in specific directions. However, by conducting dilatometer tests in boreholes oriented in different directions or taking impression packer data in any test intervals that had developed a hydraulic type fracture, some aspects of the in situ anisotropic conditions could be obtained. 1.4 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. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 1.4.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In the system, the pound (lbf) represents a unit of force (weight), while the units for mass is slugs. The slug unit is not given, unless dynamic (F = ma) calculations are involved. 1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.5.1 The procedures used to specify how data are collected/recorded or calculated in the 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, a 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 this standard to consider significant digits used in analysis methods for engineering design. 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 dilatometer test is usually performed in vertical boreholes. It can be used in inclined or horizontal holes, but the probe would drag along the borehole wall. 5.2 Deformation modulus of rock, creep characteristics, rebound, and permanent set data is obtained and is useful for engineering designs. 5.3 The rock mass discontinuities, in situ stresses, geologic history, crystallography, texture, fabric, and other factors will determine the rock mass properties that laboratory size tests alone may not be able to measure and that the dilatometer test may be better able to measure. 5.4 Determination of rock mass deformability yields a critical parameter in the design of foundations of dams, support of underground excavations, piers, caissons, and stability of rock slopes. Note 2: Although a rock mass behaves in an anisotropic and inhomogeneous manner, the calculations for a rock mass deformation modulus are based on assumptions of elasticity and homogeneity. However, they still render results that are practical, simple, usable, and not significantly different from those obtained using inhomogeneity and inelasticity. Note 3: The existing in situ stresses can only be estimated by in situ tests on the rock mass, such as this or other tests. 5.5 In situ tests such as this one provides general information regarding rock mass behavior. Dilatometer tests are advised when designing and constructing specific structures. 5.6 Dilatometer tests can be performed at a reasonable cost and effort. Dilatometer tests are also less expensive and time-consuming compared to other deformability tests like radial jack or flexible plate tests that require underground excavation and access too. 5.7 Dilatometer modulus can be correlated with the moduli obtained by other methods (for example, the plate loading or radial jacking methods). The correlated dilatometer modulus can then be used instead of other more expensive in situ modulus tests. 5.8 Dilatometer tests can provide a qualitative evaluation of a rock mass deformability before performing a large scale deformability test such as a radial jack test. 5.9 Dilatometers are valuable for rapid index logging of boreholes in jointed rocks that yield poor core recovery and inadequate specimens for laboratory testing. 5.10 Pressurization and depressurization of the dilatable membrane in this standard are unique. This is done immediately upstream of the dilatable membrane by a dual-action piston actuated from a manual pump at the surface. This configuration allows the use of the dilatometer at substantial depths and eliminates the parasitic expansion of the tubing and pumping system and forces the membrane to collapse completely regardless of if the drill hole column has fluid or not. 5.11 The results of dilatometer tests may be used to check against the serviceability limit state of spread foundations on rocks through a deformation analysis. 5.12 When performing a deformation analysis the Young's modulus, E , may be taken equal to E d on the assumption that the rock is linearly elastic and isotropic. Note 4: 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 facilities used. 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.