ASTM D4394-17 PDF Download

ASTM D4394-17 is a standard test method that outlines the procedure for determining the in situ modulus of deformation of rock mass using the rigid plate loading method. The results obtained from this test method are crucial for predicting displacements in rock mass caused by loads from structures or underground construction. It is important to note that this test should be performed in conjunction with other tests to obtain a comprehensive understanding of the rock mass behavior.

The modulus of deformation is determined by applying a uniformly distributed load over a circular area on a semi-infinite elastic medium. This load produces a constant normal displacement of the loaded surface area. The test is typically conducted at ambient temperature, but modifications can be made to accommodate other temperature conditions.

It should be emphasized that the accuracy and reliability of the results obtained from this test method depend on the competence of the personnel conducting the test and the suitability of the equipment and facilities used. Compliance with Practice D3740, which provides criteria for competent and objective testing, sampling, and inspection, is recommended. However, compliance with Practice D3740 does not guarantee reliable results as reliable results depend on several factors.

The standard also provides information on the preparation, equipment, test procedure, and data reduction for conducting the test. It specifies that the test method is primarily designed for use in adits or small underground chambers, but with modifications, it can also be conducted at the surface. The test can be conducted parallel or perpendicular to the anticipated axis of thrust and on diametrically opposite surfaces.

Additionally, the standard mentions that both instantaneous deformation and primary creep can be obtained from this test method. It briefly discusses time-dependent tests, but reporting of such tests is covered in another standard. The standard also provides guidelines for significant digits and rounding of observed and calculated values, following the principles outlined in Practice D6026.

References appended to the standard offer further information on the test method.