Rock quality designation rqd or mdifidc rmodified core recovery x rqd i. What is rqd rock quality designation and how to calculate it. Coring bits the coring bit is the bottommost component. T1 determination and applications of rock quality designation rqd au zhang, lianyang. Spatial mapping of the rock quality designation using. An astm designation number identifies a unique version of an astm standard. Pdf determination and applications of rock quality. High quality rock has an rqd of more than 75%, low quality of less than 50% table 1. Supplementary notation available from national technical information service, 5285 port royal road, springfield. Underground excavation design classification alfred zettler rock mass rating rmr.
N2 characterization of rock masses and evaluation of their mechanical properties are important and challenging tasks in rock mechanics and rock engineering. Introduction rqd stands for the rock quality designation and represents a rock mass classification system, based on the rqd index as a classification parameter for a quantitative estimation of the quality of rock mass. It is concluded that the rqd measurements are encumbered with several. Astmd6032 standard test method for determining rock. The rock quality designation rqd rock quality designation rqd rough is the measure of the degree of jointing or fractures in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. To determine the rqd value, add the total length of solid core that is 4 inches 100 mm or more long regardless of core diameter. Since in many cases rock quality designation rqd is the only rock mass classification index available, this paper outlines the key aspects on determination of. Pieces of core that are not hard and sound should not be included in the rqd evaluation even if they are at least 100 mm in length. Pdf correlation of pwave velocity with rock quality. One indicator of rock quality and the degree of fracturing is a simple characterization known as the rock quality designation rqd. Application and improvement of rock quality designation rqd. Rock quality designation an overview sciencedirect topics.
Rock quality designation rqd is a modified core recovery percentage in which the lengths of all sound. A measure of rock mass integrity based on the condition of core samples. American society for testing and materials reprinted from the. A general description of rock mass quality based on rqd is shown in the table below. Standard test method for determining rock quality designation. Designation usbr 602509 procedure for sampling and quality evaluation testing of rock for riprap slope protection this procedure is under the jurisdiction of the materials engineering and research laboratory, code 8668180, technical service center, denver, colorado.
Highquality rock has an rqd of more than 75%, low quality of less than 50% table 1. Since in many cases rock quality designation rqd is the only rock mass classification index available, this paper outlines the key aspects on determination of rqd and evaluates the empirical methods based on rqd for determining the deformation modulus and unconfined compressive strength of rock masses. Prediction of side resistance in poor quality rock. American society for testing and materials reprinted from. All pieces of intact rock core equal to or greater than 100 mm 4 in. Oct 18, 2012 an instructional video about rqd, a strength determining technique used by geologist and geological engineers. Determination and applications of rock quality designation rqd article pdf available in journal of rock mechanics and geotechnical engineering 83 march 2016 with 4,540 reads. The rock quality designation rqd index in practice. Rock quality designation rqd is a modified core recovery percentage in which the lengths of all sound rock core pieces over 100 mm in length are summed and divided by the length of the core run. The rqd in percent is obtained by dividing the sum of all the. Rqd signifies the degree of jointing or fracture in a rock mass measured in percentage, where rqd of 75% or more shows good quality hard rock and less than 50% show low quality weathered rocks.
Tunnel design by rock mass classifications 12 personal authors bieniawski, z. The rock quality designation rqd was developed as an index of rock quality and was first used on a design and construction job in 1964, and on two additional jobs in 19641965. Rock quality designation rqd was introduced by don deere in the mid1960s as a means of using diamond core to classify rock for engineering purposes. Subsequently, it was incorporated into the rock mass rating rmr and q system classification methods that, worldwide, now play substantial roles in rock mechanics design, whether for tunnels. Determination and applications of rock quality designation rqd. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. Coring bits the coring bit is the bottommost component of the core barrel assembly. Rock quality designation rock quality designation rqd 2 is a fracture index used in many rock classification systems. When using rock quality designation rqd method to evaluate rock mass integrity, the premises are often neglected and there are some limitations in rqd method. Determination and applications of rock quality designation. Pdf rock quality designation rqd soukaina cherradi. Banks, chief, engineering geology and rock mechanics.
It was developed by the senior author originally as a means of qualitatively describing whether a rock mass provided. The geomechanics classification for rock mass rating is more comprehensive. Measurements of and correlations between block size and. Rock quality designation rqd is a measure of quality of rock core taken from a borehole. Determining rock quality designation rqd of rock core1 this standard is issued under the. This study proposes a hole section statistical method and a rock block coefficient to supplement and improve the limitations of rqd method. Rqd, rock mass, classification, discontinuity, rock quality 1. Rock quality designationdesignator how is rock quality. Rqd is defined as the percentage of intact drill core pieces longer than 10 cm recovered during a single core run abzalov, 2016, and the general equation is expressed as. Geomechanics classification although initially developed for tunnels, has been appliied. Shorter core runs often reduce the degree of damage to the core and improve core recovery in poor quality rock. The rock quality designation is an important input for the analysis and design of rock structures as reliable spatial modeling of the rock quality designation rqd can assist in designing and planning mines more efficiently. Rock quality designation index rqd the rock quality designation index rqd was developed by deere deere et al 1967 to provide a quantitative estimate of rock mass quality from drill core logs.
Rockquality designation rqd rough is the measure of the degree of jointing or fractures in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. Rqd is most useful if used with other known parameters that can account for rock strength, deformability, and discontinuity characteristics. The qsystem for rock mass classification is developed by barton, lien, and lunde. Rock mass characterization rock quality designation rqd. The rqd is measured when coring rock, and is defined as the sum of the lengths of rock. Rock quality designation rqd a measure of rock mass integrity based on the condition of core samples. It measures the percentage of good rock within a borehole. Pdf determination and applications of rock quality designation. The procedure is issued under the fixed designation usbr 6025. Scribd is the worlds largest social reading and publishing site. Rock quality designation rqd is a standard technique in the mining industry for the qualitative and quantitative assessment of rock quality and degree of jointing, fracturing, and shearing in a rock mass.
Application and improvement of rock quality designation. Procedure for sampling and quality evaluation testing of. Pdf rock quality designation rqd was introduced by don deere in the mid 1960s as a means of using diamond core to classify rock for. Rfq is calculated by taking a rock core sample from a. Active standard astm d6032 d6032m developed by subcommittee. Rock quality designation rqd has several definitions. University of tennessee at chattanooga ence 3610l soils. Determining rock quality designation rqd of rock core1. D 6032 96 standard test method for determining rock quality designation rqd of rock core1 this standard is issued under the. The aim of this paper is to model the spatial distribution of the rqd using the multigaussian kriging approach as an alternative to the nonlinear geostatistical.
Chapter 5 soil and rock classification and logging nysdot geotechnical page 54 june 17, 20 design manual 5. Notes or rock core logging for engineering purposes. Measurements of and correlations between block size and rock quality designation rqd arild palmstrom, ph. The rock quality designation rqd index has been used for over 20 years as an index of rock quality. Assessment of the quality of rock mass rqd rock quality designation, table 7. Rock quality designation rqd is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. The rock quality designation rqd is a modified measure of recovery, calculated in order to estimate the quality of the intact rock mass. Rockquality designation rqd rough is the measure of the degree of jointing or fractures in a rock mass, measured as a percentage of the drill core in lengths of. The engineering geologist is responsible for the determination of rqd. Core recovery and rqd rock quality designation the easiest way to characterize the amount of material recovered during rock coring is to calculate core recovery as the amount i. Rock quality designation rqd was introduced by don deere in the mid. High quality rock has an rqd of more than 75%, low quality of less than 50%.
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