Standard Test Method for Determining Rock Quality Designation (RQD) of Rock Core

Importancia y uso:

5.1 The RQD was first introduced in the mid 1960s to provide a simple and inexpensive general indication of rock mass quality to predict tunneling conditions and support requirements. The recording of RQD has since become virtually standard practice in drill core logging for a wide variety of geotechnical explorations.

5.2 The use of RQD values has been expanded to provide a basis for making preliminary design and constructability decisions involving excavation for foundations of structures, or tunnels, open pits, and many other applications. The RQD values also can serve to identify potential problems related to bearing capacity, settlement, erosion, or sliding in rock foundations. The RQD can provide an indication of rock quality in quarries for issues involving concrete aggregate, rockfill, or large riprap.

5.3 The RQD has been widely used as a warning indicator of low-quality rock zones that may need greater scrutiny or require additional borings or other investigational work. This includes rocks with certain time-dependent qualities that by determining the RQD again after 24 h, under well-controlled conditions, can assist in determining durability.

5.4 The RQD is a basic component of many rock mass classification systems, such as rock mass rating (RMR) and Q-System, for engineering purposes. See D5878 and 2^,3.

5.5 When needed, drill holes in different directions can be used to determine the RQD in three dimensions.

5.6 The concept of RQD can be used on any rock outcrop or excavation surface using line surveys as well. However, this topic is not covered by this standard.

Note 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

Subcomité:

D18.12

Referida por:

D0420-18, D5878-19, D8359-21

Volúmen:

04.09

Número ICS:

13.080.99 (Other standards related to soil quality), 73.100.30 (Equipment for drilling and mine excavation)

Palabras clave:

classification; index; logging; quality; rock; rock core ;