1.1 本试验方法包括土工格栅孔径稳定模量的测量程序。（文献中使用了术语“割线孔径稳定模量”、“扭转刚度模量”、平面内剪切模量和“扭转刚性模量”来描述这种相同的特性。） 1.2 该试验方法旨在通过夹紧中心节点并测量土工格栅某一区域的刚度来确定土工格栅的平面内稳定性。本试验方法适用于各种类型的土工格栅。 1.3 此测试方法旨在为设计提供特性。 该试验方法是为路面和路基改良而开发的，校准设计方法需要输入孔隙稳定模量。 1.4 以国际单位制或英寸磅单位表示的数值应单独视为标准。每个系统中规定的值不一定是完全相等的；因此，为了确保符合标准，每个系统应独立使用，并且两个系统的值不得合并。 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）。本标准的使用者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。 1.6 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 孔隙稳定模量是平面内剪切模量的测量值，该模量是其他土工格栅特性的函数，最显著的是连接稳定性、弯曲肋刚度和肋拉伸模量。 5.2 试验数据可与解释方法结合使用，以评估土工格栅在各种交通荷载和基底/路基条件下的孔隙稳定性。 注1: 《美国联邦公路管理局土工合成材料设计和施工指南》（2008）中引用了孔径稳定模量，作为使用冲压和拉伸双轴土工格栅设计土工格栅加固未铺砌道路的输入参数。不同制造工艺和材料成分的土工格栅可在相关设计中使用该特性对其材料进行校准和验证。 5.3 本试验方法不适用于土工格栅的常规验收试验。该试验方法应用于表征拟用于孔径稳定性相关应用的土工格栅。

1.1 This test method covers the procedure for measuring the Aperture Stability Modulus of a geogrid. (The terms “Secant Aperture Stability Modulus,” “Torsional Rigidity Modulus,” “In-plane Shear Modulus,” and “Torsional Stiffness Modulus” have been used in the literature to describe this same property.) 1.2 This test method is intended to determine the in-plane stability of a geogrid by clamping a center node and measuring the stiffness over an area of the geogrid. This test method is applicable for various types of geogrid. 1.3 This test method is intended to provide characteristic properties for design. The test method was developed for pavement and subgrade improvement calibrated design methods requiring input of aperture stability modulus. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 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 aperture stability modulus is a measure of the in-plane shear modulus, which is a function of other geogrid characteristics, most notably junction stability, flexural rib stiffness, and rib tensile modulus. 5.2 The test data can be used in conjunction with interpretive methods to evaluate the geogrid aperture stability at various traffic loads and base/subgrade conditions. Note 1: Aperture stability modulus is referenced in the FHWA Geosynthetics Design and Construction Guidelines (2008) as an input parameter for the design of geogrid-reinforced unpaved roads using punched and drawn biaxial geogrids. Geogrids of different manufacturing process and material composition may use this property in calibration and validation of their material within the associated design. 5.3 This test method is not intended for routine acceptance testing of geogrid. This test method should be used to characterize geogrid intended for use in applications in which aperture stability is considered relevant.