1.1 该试验方法适用于测定马运动表面中使用的压实、排水粘性天然或合成土壤表面的圆柱形试样的强度和应力-应变关系。试样在压缩过程中以恒定的轴向变形速率（应变控制）进行各向同性固结和剪切。 1.2 马运动表面材料的剪切强度描述了材料对表面层滑动的阻力。剪切强度影响蹄在轨道表面的滑动和穿透。人们普遍认为，在冲击时需要少量滑动 ( 1- 3. ) . 2. 然而，表面必须具有足够的剪切强度，以在推进过程中支撑马 ( 1- 5. ) . 因此，马术表面的最佳剪切强度是预期的。 1.3 为了确定马运动表面的剪切强度，将具有代表性的泥土或合成样品放置在圆柱形细胞中，并施加垂直载荷。根据试验方法中概述的程序测量剪切强度 D4767 用于实验室合并样本。本ASTM标准由赛马表面测试实验室针对排水条件进行了调整，以更准确地模拟马术表面的条件。 1.4 在一系列成型含水量范围内测试污垢样品，以确定给定能量输入的最大体积密度和最佳成型含水量。然后在该最佳含水量下压实土样。假设最大应力破坏标准，结果表示为15 psi围压下的破坏应力与样品形成含水量，以及摩擦角和内聚力。 1.5 排水良好的合成样品在4%的成型含水量和规定的温度范围内进行测试。使用加热/制冷水浴器控制温度，水浴器带有三轴电池盖，电池盖配有铜线圈。 在类似条件下，假设污垢表面的破坏标准，结果显示为15 psi围压下的破坏应力与样品温度，以及摩擦角和内聚力。 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 测试描述材料如何抵抗表层滑动的材料的剪切强度。这些测试的数据用于计算表面样品的摩擦角和内聚力。该测试可用于帮助确定材料是否属于适合马运动的表面。

1.1 This adapted test method covers the determination of strength and stress-strain relationships of a cylindrical specimen of a compacted, drained cohesive natural or synthetic soil surface used in equine sports surfaces. Specimens are isotropically consolidated and sheared in compression at a constant rate of axial deformation (strain controlled). 1.2 The shear strength of an equine sports surface material describes the resistance of the material to sliding of the surface layers. Shear strength influences both slide and penetration of the hoof in the track surface. It is generally accepted that a small amount of slide on impact is desirable ( 1- 3 ) . 2 However, the surface must have sufficient shear strength to support the horse during propulsion ( 1- 5 ) . Thus, an optimal shear strength would be expected for an equestrian surface. 1.3 To determine the shear strength of an equine sports surface, a representative dirt or synthetic sample is placed into a cylindrical cell and a vertical load is applied. Shear strength is measured as per the procedures outlined in Test Method D4767 for lab-consolidated samples. This ASTM standard was adapted by Racing Surfaces Testing Laboratory for the drained condition to more accurately model the conditions of an equestrian surface. 1.4 Dirt samples are tested over a range of forming moisture contents to determine the maximum bulk density and optimal forming moisture content for a given energy input. The dirt samples are then compacted at this optimal moisture content. The maximum stress failure criteria is assumed and results are presented as the failure stress at 15 psi confining pressure versus sample forming moisture content, along with friction angle and cohesion. 1.5 Synthetic samples with good drainage are tested at a 4% forming moisture content, and over a specified range of temperatures. The temperature is controlled using a heated/refrigerated water bath with a triaxial cell cap fitted with a copper coil. Failure criteria is assumed under similar conditions for the dirt surfaces, and results are presented as the failure stress at 15 psi confining pressure versus sample temperature, along with friction angle and cohesion. 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 To test the shear strength of a materials describing how the material resists sliding of surface layers. Data from these tests are used to calculate the friction angle and cohesion of a surface sample. This test can be used to help determine if a material falls within a suitable for equine sports surfaces.