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GUIDELINES FOR CORE LOGGING - University of North …

Chapter 10 GUIDELINES FORCORE LOGGINGT hese GUIDELINES incorporate procedures and methodsused by many field offices and are appropriate for"standard" engineering geology/geotechnical log forms,computerized log forms, and many of the modified logforms used by various Bureau of Reclamation(Reclamation) chapter describes the basic methods for engineeringgeology core LOGGING and provides examples andinstructions pertaining to format, descriptive data, andtechniques; procedures for working with drillers to obtainthe best data; caring for recovered core; and water testingin drill holes. The chapter also provides a reference forexperienced loggers to improve their techniques and trainothers. Most of the discussions and examples shownpertain to LOGGING rock core, but many discussions applyto soil core LOGGING , standard penetration resistance logs,and drive tube sample , Use, and Importance of Quality CoreLoggingThe ability of a foundation to accommodate structureloads depends primarily on the deformability, strength,and groundwater conditions of the foundation remediation of a hazardous waste site can beformulated only by proper characterization of the and accurate portrayal of geologic design andevaluation data and analytical procedures is reported in geologic logs not only must be accurate,FIELD MANUAL250 consistently recorded, and concise, but also must provi

Data Required for the "Drilling Notes" Column Data for the left-hand column of all drill hole logs are similar whether for large-diameter sampling, Standard Penetration Tests, rock core, or push-tube sampling logs. These data are field observations and information provided by the driller on the Daily Drill Reports.

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Transcription of GUIDELINES FOR CORE LOGGING - University of North …

1 Chapter 10 GUIDELINES FORCORE LOGGINGT hese GUIDELINES incorporate procedures and methodsused by many field offices and are appropriate for"standard" engineering geology/geotechnical log forms,computerized log forms, and many of the modified logforms used by various Bureau of Reclamation(Reclamation) chapter describes the basic methods for engineeringgeology core LOGGING and provides examples andinstructions pertaining to format, descriptive data, andtechniques; procedures for working with drillers to obtainthe best data; caring for recovered core; and water testingin drill holes. The chapter also provides a reference forexperienced loggers to improve their techniques and trainothers. Most of the discussions and examples shownpertain to LOGGING rock core, but many discussions applyto soil core LOGGING , standard penetration resistance logs,and drive tube sample , Use, and Importance of Quality CoreLoggingThe ability of a foundation to accommodate structureloads depends primarily on the deformability, strength,and groundwater conditions of the foundation remediation of a hazardous waste site can beformulated only by proper characterization of the and accurate portrayal of geologic design andevaluation data and analytical procedures is reported in geologic logs not only must be accurate,FIELD MANUAL250 consistently recorded, and concise, but also must providequantitative and qualitative provide fundamental data on which conclusionsregarding a site are based.

2 Additional exploration ortesting, final design criteria, treatment design, methodsof construction, and eventually the evaluation of structureperformance may depend on core logs. A log may presentimportant data for immediate interpretations or use, ormay provide data that are used over a period of log may be used to delineate existing foundationconditions, changes over time to the foundation orstructure, serve as part of contract documents, and maybe used as evidence in negotiations and/or in court toresolve contract or possible responsible party (PRP) engineering geology purposes, the basic objectives oflogging core are to provide a factual, accurate, and conciserecord of the important geological and physical character-istics of engineering significance. Characteristics whichinfluence deformability, strength, and water conditionsmust be recorded appropriately for future interpretationsand analyses. Reclamation has adopted recognizedindexes, nomenclature, standard descriptors anddescriptive criteria, and alphanumeric descriptors forphysical properties to ensure that these data are recordeduniformly, consistently, and accurately.

3 Use of alpha-numeric descriptors and indexes permits analysis of databy computer. These descriptors, descriptive criteria,examples, and supporting discussions are provided inchapters 3, 4, and should be logged or, as a minimum, reviewedby an experienced engineering geologist. The loggershould be aware of the multiple uses of the log and theneeds and interests of technically diverse users. TheCORE LOGGING251 experienced logger concentrates on the primary purposesof the individual drill hole as well as any subordinatepurposes, keeping in mind the interests of others withvaried geological backgrounds including geotechnicalengineers, contract drillers, construction personnel, andcontract lawyers. An experienced logger tailors the log tomeet these needs, describing some seemingly minorfeatures or conditions which have engineeringsignificance, and excluding petrologic features or geologicconditions having only minor or academic interest.

4 Lessexperienced loggers may have a tendency to concentrateon unnecessary garnishment, use irrelevant technicalterms, or produce an enormously detailed log whichignores the engineering geology considerations andperhaps the purpose for completing the drill descriptions of recovered cores and samples canbe prepared solely through visual or hand specimenexamination of the core with the aid of simple field microscopic or laboratory testing to define rocktype or mineralogy generally are necessary only in design methods, such as the Rock Mass RatingSystem Geomechanics Classification (RMR) and Q-systemClassification (Q), are commonly used for design of under-ground structures and are coming into common use forother structures as well. If these methods are used, thenecessary data must be collected during core LOGGING . If hazardous waste site characterization is the primarypurpose of the drilling, the log should concentrate onproviding data for that type of and LOGGING are to determine the in-placecondition of the soil or rock mass.

5 Any core condition,core loss, or damage due to the type of bit, barrel, or otherequipment used, or due to improper techniques used inFIELD MANUAL252 the drilling and handling processes should be factors may have a marked effect on the amount andcondition of the core recovered, particularly in soft,friable, weathered, intensely fractured materials or zonesof shearing. Geologic logs require the adequatedescription of materials; a detailed summary of drillingequipment, methods, samplers, and significantengineering conditions; and geologic geologic logs of drill holes require adequatedescriptions of recovered surficial deposits and bedrock,a detailed summary of drilling methods and conditions,and appropriate physical characteristics and indexes toensure that adequate engineering data are available forgeologic interpretation and and Required Data for theFinal Geologic LogOrganization of the LogThe log forms are divided into five basic sections: aheading block; a left-hand column for notes; a center col-umn for indexes, additional notes, water tests andgraphics; a right-hand column for classification andphysical conditions; and a comments/explanation block atthe bottom.

6 Data required for each column are describedin the following discussion and the referenced examplelogs. Log DH-123, figure 10-1, and log B-102, figure 10-2,are the most complete and preferred examples; othervariations are presented but in some cases are heading block at the top of the form provides spacesfor supplying project identifying information, feature,CORE LOGGING253 Figure 10-1. Drill hole log, DH-123, sheet 1 of MANUAL254 Figure 10-1. Drill hole log, DH-123, sheet 2 of LOGGING255 Figure 10-2. Drill hole log, B-102, for StandardPenetration Test, sheet 1 of MANUAL256 Figure 10-2. Drill hole log, B-102, for StandardPenetration Test, sheet 2 of LOGGING257 Figure 10-2. Drill hole log, B-102, for StandardPenetration Test, sheet 3 of MANUAL258hole number, location, coordinates, elevation, bearing andplunge of hole, dates started and completed, and thename(s) of the person(s) responsible for LOGGING and re-view. Locations should preferably be in coordinatesunless station and offset are all that is available.

7 Provide both coordinates and station and offset ifavailable. The dip or plunge of the hole can be the anglefrom horizontal or from vertical, but the reference pointshould be noted on the log. Spaces for depth to bedrockand water levels are also provided. All this informationis important and should not be omitted. Below theheading, the body of the log form is divided into a seriesof columns covering the various kinds of informationrequired according to the type of exploratory Required for the "Drilling Notes" ColumnData for the left-hand column of all drill hole logs aresimilar whether for large-diameter sampling, StandardPenetration Tests, rock core, or push-tube sampling data are field observations and informationprovided by the driller on the Daily Drill are provided for some of these data headings;a suggested guideline and preferred order is presented inthe following paragraphs but may differ depending on thepurpose and type of exploration.

8 Headers for data canindicate whether depths are in feet (ft) or meters (m),eliminating the need to repeat "ft" or "m" for each intervalentry. An example of the Drilling Notes column isprovided on figures 10-1 through Information. This includes headers and datafor the hole purpose, the setup or site conditions, drillers,and drilling and testing equipment LOGGING259 Figure 10-3. Drill hole log, DH-SP-2, sheet 1 of MANUAL260 Figure 10-3. Drill hole log, DH-SP-2, sheet 2 of LOGGING261 Figure 10-4. Drill hole log, SPT-107-2, sheet 1 of MANUAL262 Figure 10-4. Drill hole log, SPT-107-2, sheet 2 of LOGGING263 Figure 10-4. Drill hole log, SPT-107-2, sheet 3 of MANUAL2641. Purpose of hole Includes reason for drillingthe hole, such as foundation investigation, materialsinvestigation, instrumentation, sampling, or Drill site or setup Includes general physicaldescription of the location of the drill on unusual setups, such as adjacent toa stream, or drilled from a barge, gallery, or adit,may help understand the unusual Drillers Names of drillers may be significantfor reference or for evaluating or interpreting corelosses, drilling rates, and other drilling Drilling equipment Drill rig (make and model) Core barrel(s), tube(s), special samplers (typeand size) Bits (type and size) Drill rods (type and size) Collar (type) Water test equipment (rod or pipe size, hosesize, pump type and capacity, and relativeposition and elevation of pressure gauges ortransducers), packers (type mechanical orpneumatic)Example: Skid-mounted Sprague and HenwoodModel 250.

9 NWD3 bottom discharge bit with a5-ft ( ), split-tube inner barrel. 5-ft ( )NW rods. Water tested with NX pneumaticCORE LOGGING265packer No. 12 with 1-1/4-inch (in) (32-millimeter[mm]) pipe, Bean pump with 35-gallons perminute (gal/min) (159 liters per minute)maximum volume, and 1-in (25-mm) watermeter. (Water testing equipment can be aseparate heading if desired.)Drilling Procedures and Conditions. These headersand data should include methods, conditions, driller'scomments, and records for water losses, caving, or Drilling methods Synopsis of drilling, sam-pling, and testing procedures, including proceduresand pressures for drive or push tubes used throughthe various intervals of the Drilling conditions and driller's comments Note by interval the relative penetration rate andthe action of the drill during this process ( , : drilled slowly, moderate blocking off, holeadvancing 15 minutes per foot [.3 meter]). Unusualdrilling conditions should be summarized.

10 Changesin drilling conditions may indicate differences inlithology, weathering, or fracture density. Thegeologist needs to account for variations in driller'sdescriptions; each driller may describe similarconditions with different adjectives or percentageestimates. Any other comments relative to ease ordifficulty of advancing or maintaining the holeshould be noted by depth intervals. Drillers'comments need to adequately describe conditionsencountered while advancing the hole. Statementssuch as "normal drilling" or "no problemsencountered" are not in drilling speeds, pressures, andpenetration rates may be related to the relativeFIELD MANUAL266hardness and density of materials. Abrupt changesin drilling time may identify lithologic changes orbreaks and also may pinpoint soft or hard interbedswithin larger units. Often, these may be correlatedwith geophysical logs. If the driller provides usefuland accurate records of drilling conditions andprocedures, an accurate determination of the top andbottom of key marker horizons can be made evenwithout progress should be recorded while drilling;recovery can be improved by relating recovery tooptimum pressures and speeds, as well as providingdata for interpretation.


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