Geosynthetics experience load simultaneously in each principal material direction in applications such as retaining walls, constructed slopes, roadways, and reinforced granular load transfer platforms. Biaxial loading results in a stiffer load-strain response compared to that observed in uniaxial loading. Load-strain properties of geosynthetics determined from wide-width uniaxial tension tests are unable to account for this effect and are generally regarded as an index test. This paper presents the development of a biaxial testing procedure to provide load-strain response data necessary to determine in-plane linear elastic tensile properties of geosynthetics. These properties consist of two elastic moduli, two dependent in-plane Poisson's ratios and an in-plane shear modulus. The elastic moduli and Poisson's ratios are derived from non-bias biaxial tests where load is applied in the two principal directions of the material. The in-plane shear modulus is determined from biaxial tests on specimens where load is applied on a bias such that the principal material directions are oriented at a 45-degree angle to the test machine directions. The tests are performed on geosynthetics that have been load conditioned such that the subsequent load-strain response is considered to be a resilient response pertinent to repetitive load applications such as geosynthetic reinforced pavements.

中文翻译：

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来自空气双轴拉伸试验的土工合成材料的平面内弹性特性

土工合成材料在诸如挡土墙、人工斜坡、道路和加固颗粒荷载传递平台等应用中同时承受每个主要材料方向的荷载。与在单轴加载中观察到的相比，双轴加载导致更硬的负载应变响应。由宽幅单轴拉伸试验确定的土工合成材料的载荷-应变特性无法解释这种影响，通常被视为指标试验。本文介绍了双轴测试程序的发展，以提供确定土工合成材料平面线弹性拉伸性能所需的载荷-应变响应数据。这些属性包括两个弹性模量、两个相关的平面内泊松比和平面内剪切模量。弹性模量和泊松' s 比率来自无偏置双轴试验，其中载荷施加在材料的两个主要方向上。面内剪切模量由试样的双轴试验确定，其中载荷施加在偏置上，使得主要材料方向与试验机器方向成 45 度角。这些测试是在经过负载调节的土工合成材料上进行的，因此随后的负载应变响应被认为是与重复负载应用（如土工合成材料加固路面）相关的弹性响应。面内剪切模量由试样的双轴试验确定，其中载荷施加在偏置上，使得主要材料方向与试验机器方向成 45 度角。这些测试是在经过负载调节的土工合成材料上进行的，因此随后的负载应变响应被认为是与重复负载应用（例如土工合成材料加固路面）相关的弹性响应。面内剪切模量由试样的双轴试验确定，其中载荷施加在偏置上，使得主要材料方向与试验机器方向成 45 度角。这些测试是在经过负载调节的土工合成材料上进行的，因此随后的负载应变响应被认为是与重复负载应用（例如土工合成材料加固路面）相关的弹性响应。