ASTM D4506-21 PDF Download

ASTM D4506-21 is a standard test method used to determine the in situ modulus of deformation of a rock mass using the radial jacking test. The test involves subjecting a test chamber in a rock of circular cross-section to uniformly distributed radial loading. The resulting rock radial displacements are measured at various locations, and from these measurements, the deformation modulus of the rock mass can be calculated.

The standard provides guidance on the procedures and equipment required to conduct the test. It mentions two methods that can be used: the US Bureau of Reclamation method and the New Austrian method. Both methods involve taking deformation readings, but differ in the way they are done. The standard also discusses considerations such as time-dependent deformation and the effects of in situ stresses on test results.

The scope of the standard does not cover the application of the test results, as their interpretation and use may vary depending on the specific testing program and objectives. It also mentions limitations, such as the maximum stress range of the reaction frame and the flat jacks, which may restrict the testing of rock deformation behavior.

The standard includes information on units of measurement, specifying that the SI units presented are substitutions for inch-pound units, but other similar SI units may be acceptable. It also addresses rounding and significant digits in measurements, referring to the guidelines established in Practice D6026.