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Tuesday, July 28, 2020 | History

2 edition of Core index, a numerical core-logging procedure for estimating rock quality found in the catalog.

Core index, a numerical core-logging procedure for estimating rock quality

Ege, John R.

Core index, a numerical core-logging procedure for estimating rock quality

by Ege, John R.

  • 218 Want to read
  • 31 Currently reading

Published by U.S. Geological Survey in [Reston] .
Written in English


Edition Notes

Statementby John R. Ege.
SeriesU.S. Geological Survey circular -- 954
ContributionsUnited States. Geological Survey.
The Physical Object
Paginationiii, 15p. ;
Number of Pages15
ID Numbers
Open LibraryOL13909901M

and improve core recovery in poor quality rock. Coring Bits The coring bit is the bottommost component of the core barrel assembly. It is the grinding action of this component that cuts the core from the rock mass. Three basic categories of bits are in use: diamond, carbide insert, and sawtooth (Figure ). Core Laboratories will normally run these tests on every sample. This would also include all core handling and sample acquisition required to provide samples for these measurements, as well as other special core analysis and petrographic analysis. Our range of Rock Properties services includes: Advanced Rock Properties.

Basic Rock Properties. Conventional Core Analysis. Conventional core analysis is the starting point for a wide range of geologic and engineering services provided by Core Laboratories. Over the years the line between what has historically been considered "conventional or routine" core analysis and more advanced analysis has blurred. The rock mass rating (RMR) is a geomechanical classification system for rocks, developed by Z. T. Bieniawski between and Since then it has undergone multiple modifications out of which, RMR89 is commonly used. Recently RMR14 has been proposed to improve the RMR performance by incorporating new experiences from tunnel practices. Continuous functions and a software .

Review: GSI and Hoek‐Brown Procedure The presence of geological structures within a rock mass (joints, shears, etc.), requires that consideration be given to the combined influence of intact rock blocks and discontinuities when calculating the rock mass' response to tunnelling. Other articles where Core logging is discussed: well logging: Core logging is a highly specialized skill requiring careful observation and accurate recording. Geophysical logging of the hole created in the drilling process is sometimes done without the collection of the core. Logging techniques are extremely useful, dependable, and accurate for lithologic identification, formation evaluation,.


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Core index, a numerical core-logging procedure for estimating rock quality by Ege, John R. Download PDF EPUB FB2

The core index, a numerical core-logging procedure used by the U.S. Geological Survey since in engineering-geology projects at the Nevada Test Site and other locales, provides an objective means for estimating rock quality.

The logging concept is based on the observation that rock-mass strength is reduced by discontinuities cutting the by: 2. Get this from a library. Core index: a numerical core-logging procedure for estimating rock quality. [John R Ege; Geological Survey (U.S.)].

An independent branch of rock quality measurement method is provided by Ege as the core index (CI) which is a numerical core-logging procedure. This method utilizes a combined effect of discontinuity frequency and core-loss measurement to calculate the core index number.

The smaller the CI value the better is the rock by: 7. Core Logging Handling of Core After the core has been recovered from the corehole and the core barrel has been opened, the core should be placed in a core box.

The top of the core should be placed at the back left corner of the core box, and the remaining core placed to the right of the preceding section (see Figure 8).File Size: 2MB.

A guide to core logging for rock engineering 4 Proceedings of the Symposium on Exploration for Rock Engineering / Johannesburg / November Page 71 an excellent guide for rock strata correlation and may be used to Core index various "marker" horizons.

Colour variation is. Core logging is the systematic recording and measuring of as much information as possible/required to determine the lithology (rock types), mineralogy, potential geological history, structure and alteration zones through a tiny piece of cylindrical rock drilled and removed from a potential mineral deposit.

KEY WORDS: rock mechanics, Rock Quality Designation index, modulus of deformation, jointed rock, tunnel supports, rock mass classification, core logging The Rock Quality Designation (RQD) index has been used for over 20 years as an index of rock quality.

It measures the percentage of "good" rock within a borehole. It was developed by. Note: RQD was originally developed for use with NX-size ( in.

( mm)) core drilled in crystalline rock and used to describe rock quality for tunneling conditions. It has since become virtually standard practice in drill core logging for a variety of core sizes and rock types. 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.e.

length) of recovered material divided by the total length of the core run (presented as a percentage). Rock Quality Designation (RQD) is a modified core recovery percentage in which the lengths of all. This procedure is designed to ensure valuable geological information can be derived from oriented core measurement of geological domains to unravel the tectonic evolutionary history when drilling.

pertain to logging rock core, but many discussions apply to soil core logging, standard penetration resistance logs, and drive tube sample logging. Purpose, Use, and Importance of Quality Core Logging The ability of a foundation to accommodate structure loads depends primarily on.

RFQ is calculated by taking a rock core sample from a borehole and lengths of all sound rock pieces which are minimum mm long are summed up and are divided by the length of the core run.

Only those pieces of rocks are considered which are hard and good quality. Rock Core Logging For Engineering Purposes. Paul Maconochie, GeoTek Solutions Pty Ltd. 1 Requirements of a Borehole Log “A borehole log should provide an accurate and comprehensive record of the geological conditions encountered together with an.

Rock Mass Classification is the process of placing a rock mass into groups or classes on defined relationships (Bieniawski, ), and assigning a unique description (or number) to it on the basis. Core Indices Core indices such as Rock Quality Designation (RQD) have been proposed for the logging of rock not only from borehole cores but also from the mapping of exposures, in order to provide a ready indicator of rock quality.

A number of indices and a range of definitions have been proposed, without much commonality. o We are estimating rock strength using a rock hammer. o A good test will break through intact rock. If the rock breaks along a cemented feature, vein, or microdefect this is not testing the intact rock strength.

For broken rock estimate the strength of the rock pieces. o Up to two values for IRS are given for each run. Obviously the core pieces will be of different lengths and a few pieces of timber should be available to provide a spacer on which the base of the core can rest while the orientation of the discontinuities can be measured.

Of importance in core logging is to record the Rock Quality Designation (RQD. sentative of the true quality of the rock mass. Procedure Drilling of the rock core should be done in accordance with Practice D It is important that proper drilling techniques are used to minimize core breakage or poor core recovery, or both.

There are several ways to define a core run. Three of. D Guide for Use of Direct Rotary Wireline Casing Advancement Drilling Methods for Geoenvironmental Exploration and Installation of Subsurface Water-Quality Monitoring Devices.

D Test Method for Determining Rock Quality Designation (RQD) of Rock Core. D Practice for Using Hollow-Stem Augers for Geotechnical Exploration and Soil Sampling. Geotechnical core logging is usually a very detail-oriented, slow, and rather tedious process that requires long periods of attention from the personnel doing the logging.

As such, it is imperative that competent people are responsible for the geotechnical core logging to ensure the information collected is high-quality and reliable, so that. Index Properties of Intact Rock • Specific Gravity of Solids, G s • Unit Weight, • Drilling and blasting procedures • Monitoring of stability •In-situ stresses difficult to estimate.

Rock .Make your rock core descriptions clear, consistent, and concise. Follow common procedures for identifying natural fractures, calculating Total, Solid, and Modified Core Recovery and measuring Rock Quality Designation (RQD).

Sharpen your observational skills for describing and characterizing rock core, stratigraphy and secondary rock weathering.use in enginering geology. For convenicnce the same, numerical values have been used as in Table l.

In describing the rock cores it is adviscd that the length of the pieces of the core obtained in each coring run be measured and rccorded (e. g., I pice of 20 cm, 4 pieces of 10—15 cm, and 25 pieces of 2—10 cm, etc.).

These lengths arc a direct.