1.1 本试验方法包括使用粘结电阻应变计在实验室测定岩石的线性（一维）热膨胀系数。本试验方法旨在评估完整的岩芯。岩体中的不连续性，如节理、夹杂物、孔隙、矿脉、层理等，会影响岩石的热膨胀，在选择本试验方法中要分析的试样时应进行判断。 1.2 本试验方法适用于20至260°C温度范围内的无侧限应力状态，在 6.1 . 1.3 试样可以是饱和的、干燥的或不饱和的。 如果使用饱和或不饱和试样，则试验温度应至少比饱和流体的沸点低10°C，以减少流体蒸发的影响。请参阅 6.3 和 8.4 . 1.4 单位-- 以国际单位制表示的值应被视为标准。本标准不包括其他计量单位。 1.5 所有观察值和计算值应符合《规程》中规定的有效数字和四舍五入的准则 D6026 . 1.5.1 本标准中用于规定如何收集/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。 所使用的程序不考虑材料变化、获取数据的目的、特殊目的研究或对用户目标的任何考虑；并且通常的做法是增加或减少报告数据的有效数字以与这些考虑相称。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 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。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 有关岩石热膨胀特性的信息在地下开挖和地下钻孔的设计中很重要，因为围岩的温度可能会发生变化。根据约束条件，热应变可能会导致热应力，从而影响地下开挖和钻孔的稳定性。 了解岩石热应变很重要的应用示例包括:核废料储存库、地下发电站、压缩空气储能设施、能源基础、地热能设施和用于流体注入的地下钻孔。 5.2 众所周知，岩石的线性热膨胀系数α会随着温度的变化而变化。岩石热应变通常不是温度的线性函数。该测试方法提供了一种连续监测热应变随温度变化的程序。因此，获得了关于线性热膨胀系数如何随温度变化的信息。 5.3 通过在许多度的温度范围内平均大型试样的热应变来测量岩石线性热膨胀系数的其他方法可能会导致无法确定该岩石的α变化，原因如下: 5.3.1 α并不总是与温度呈线性关系， 5.3.2 一些岩石是各向异性的，具有方向性特征，其变化可能超过两倍。如果预期存在各向异性，则应制备并测试具有不同取向的试样。 5.3.3 α在一个方向上可能为负值，而在其他方向上可能同时为正值。 5.4 线式和箔式应变计均已成功用于测量岩石的热膨胀系数。 这些系数通常非常小，每摄氏度为百万分之一毫米/毫米。岩石的热应变大约是塑料的十分之一，是许多金属的二分之一或四分之一。因此，岩石的测量方法需要比塑料和金属常规使用的方法更高的精度。 注1: 本标准产生的结果的质量取决于执行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 通常被认为有能力进行合格和客观的测试/取样/检查。 可靠的结果取决于许多因素；实习 D3740 提供了一种评估其中一些（但不是全部）因素的方法。

1.1 This test method covers the laboratory determination of the linear (one-dimensional) coefficient of thermal expansion of rock using bonded electric resistance strain gauges. This test method is intended for evaluation of intact rock cores. Discontinuities in the rock mass, such as joints, inclusions, voids, veins, bedding, and the like can influence the thermal expansion of the rock, and judgment should be used when selecting the specimen to be analyzed in this test method. 1.2 This test method is applicable for unconfined stress states over the temperature range from 20 to 260°C, within the restrictions noted in 6.1 . 1.3 The test specimens may be either saturated, dry or unsaturated. If saturated or unsaturated specimens are used, then the test temperature shall be at least 10°C less than the boiling point of the saturating fluid in order to reduce the effects of evaporation of the fluid. Refer to 6.3 and 8.4 . 1.4 Units— The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 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 procedure used to specify how data are collected/recorded or 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 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 analytical 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 Information concerning the thermal expansion characteristics of rocks is important in the design of underground excavation and subsurface boreholes where the temperature of the surrounding rock may be altered. Depending on the restraint conditions, thermal strain may cause thermal stress that may affect the stability of underground excavations and boreholes. Examples of applications where an understanding of rock thermal strain is important include: nuclear waste repositories, underground power stations, compressed air energy storage facilities, energy foundations, geothermal energy facilities, and subsurface boreholes used for fluid injection. 5.2 The coefficient of linear thermal expansion, α, of rock is known to vary as the temperature changes. Rock thermal strain is normally not a linear function of temperature. This test method provides a procedure for continuously monitoring thermal strain as a function of temperature. Therefore, information on how the coefficient of linear thermal expansion changes with temperature is obtained. 5.3 Other methods of measuring the coefficient of linear thermal expansion of rock by averaging the thermal strain of a large specimen over a temperature range of many degrees may result in failure to determine the variation in α of that rock for one or more of the following reasons: 5.3.1 α is not always linear with temperature, 5.3.2 Some rocks are anisotropic having directional characteristics which can vary by more than a factor of two. If anisotropy is expected, specimen with different orientations should be prepared and tested. 5.3.3 α may have a negative value in one direction and, at the same time, a positive value in the others. 5.4 Both wire and foil type strain gauges have been successfully employed to measure the thermal expansion coefficients of rock. These coefficients are frequently very small, being on the order of millionths of a millimetre per millimetre for each degree Celsius. The thermal strain of rocks is about one-tenth that of plastics and one-half or one-quarter that of many metals. Therefore, measurement methods for rocks require greater precision than methods that are routinely used on plastics and metals. 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.