ASTM D5311/D5311M-13 PDF Download

The ASTM D5311/D5311M-13 standard is titled "Standard Test Method for Load Controlled Cyclic Triaxial Strength of Soil". This test method is used to evaluate the ability of a soil to resist shear stresses induced by earthquakes or other cyclic loadings.

The standard specifies that the cyclic triaxial strength tests can be performed at different values of effective confining pressure on isotropically consolidated specimens to provide data on the cyclic stability of a soil. Alternatively, tests can be performed at a single effective confining pressure, usually equal to 100 kN/m^2 [14.5 lb/in^2], or alternate pressures, to compare cyclic strength results for different soil types.

The standard emphasizes that the cyclic triaxial test is a commonly used technique for determining cyclic soil strength. However, it also notes that the cyclic strength of a soil depends on various factors such as density, confining pressure, applied cyclic shear stress, stress history, grain structure, age of soil deposit, specimen preparation procedure, and the frequency, uniformity, and shape of the cyclic wave form. Therefore, careful attention must be given to testing details and equipment.

The standard also highlights certain limitations of using cyclic triaxial tests to simulate the stress and strain conditions in the field during an earthquake. These include nonuniform stress conditions within the test specimen due to specimen end platens, a 90° change in the direction of the major principal stress during the loading cycle, limitations on the maximum cyclic shear stress that can be applied to the specimen, differences in cyclic strength between intact and reconstituted specimens, and the influence of the interaction between the specimen, membrane, and confining fluid on cyclic behavior.

Note that the quality of the results produced by this standard is dependent on the competence of the personnel performing the test and the suitability of the equipment and facilities used. Compliance with the standard does not guarantee reliable results, as they depend on various factors. The standard includes a caution that users should consider the factors listed in Practice D3740 when evaluating the reliability of the test results.