ASTM D4823-95R19
Standard Guide for Core Sampling Submerged, Unconsolidated Sediments
| Standard number: | ASTM D4823-95R19 |
| Released: | 01.11.2019 |
| Status: | Active |
| Pages: | 14 |
| Section: | 11.02 |
| Keywords: | core distortion; core samplers; freeze core samplers; grab samplers; piston samplers; sampling errors; sediment sampling; surface samplers; vibratory samplers; |
| ASTM number: | ASTM D4823 |
| Supersedes: | D4823-95R14 |
This guide covers core-sampling submerged, unconsolidated sediments. It also covers terminology, advantages and disadvantages of different types of core samplers, core-distortions that may occur during sampling, techniques for detecting and minimizing core distortions, and methods for dissecting and preserving sediment cores. Sampling procedures and equipment are divided into categories based on water depth. Critical dimensions and properties of open-barrel and piston samplers like the cutting-bit angle, core-liner diameter, inside friction factor, outside friction factor, area factor, core-barrel length, barrel surfaces, and chemical composition of sampler parts shall conform to this standard guide. The following factors shall be considered for decisions in choosing between an open-barrel sampler and a piston sampler: depth of penetration, core compaction, flow-in distortion, surface disturbance, and repenetration. Driving techniques included in this guide are free core samplers, implosive and explosive samplers, punch-corer samplers, vibratory-driven samplers and impact-driven samplers. Guides are also included for collecting short cores in shallow water, collecting long cores in shallow water, and collecting short and long cores for a range of water depth. Field record shall be provided for every sampling operation. Guides are also provided for core extrusion for samplers with no liners, slitting core and core liners, sectioning cores, sampling through liner walls, preserving cores, and displaying cores.
1.1 This guide covers core-sampling terminology, advantages and disadvantages of different types of core samplers, core-distortions that may occur during sampling, techniques for detecting and minimizing core distortions, and methods for dissecting and preserving sediment cores.
1.2 In this guide, sampling procedures and equipment are divided into the following categories based on water depth: sampling in depths shallower than 0.5 m, sampling in depths between 0.5 m and 10 m, and sampling in depths exceeding 10 m. Each category is divided into two sections: equipment for collecting short cores and equipment for collecting long cores.
1.3 This guide emphasizes general principles. Only in a few instances are step-by-step instructions given. Because core sampling is a field-based operation, methods and equipment must usually be modified to suit local conditions. This modification process requires two essential ingredients: operator skill and judgment. Neither can be replaced by written rules.
1.4 Drawings of samplers are included to show sizes and proportions. These samplers are offered primarily as examples (or generic representations) of equipment that can be purchased commercially or built from plans in technical journals.
1.5 This guide is a brief summary of published scientific articles and engineering reports. These references are listed in this guide. These documents provide operational details that are not given in this guide but are nevertheless essential to the successful planning and completion of core sampling projects.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see 6.3 and 11.5.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.