Standard Active Last Updated: Mar 21, 2018
ASTM D420-18

Standard Guide for Site Characterization for Engineering Design and Construction Purposes

Standard Guide for Site Characterization for Engineering Design and Construction Purposes
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Significance and Use

4.1 An adequate site characterization will provide pertinent information for decision making on one or more of the following subjects:

4.1.1 Location of the structure, both vertically and horizontally, within the area of the proposed construction and selection of construction methods and equipment.

4.1.2 Location and preliminary evaluation of suitable borrow and other local sources of construction aggregates.

4.1.3 Need for special excavating and dewatering techniques with the corresponding need for information, even if only approximate, on the distribution of soil water content or pore pressure, or both, and on the piezometric heads and apparent permeability (hydraulic conductivity) of the various subsurface strata.

4.1.4 Evaluation of slope stability in natural slopes, cuts, and embankments.

4.1.5 Conceptual selection of embankment types and hydraulic barrier requirements.

4.1.6 Conceptual selection of alternate foundation types and elevations of the corresponding suitable bearing strata.

4.1.7 Development of additional detailed site characterizations for specific structures or facilities.

4.2 The site characterization may require the collection of sufficiently large soil and rock samples of such quality as to allow adequate testing to determine the soil or rock classification or mineralogic type, or both, and the engineering properties pertinent to the proposed design.

4.3 This guide is not meant to be an inflexible description of requirements; methods defined by other ASTM standards or non-ASTM techniques may be appropriate in some circumstances. The intent is to provide a list to assist in preparation of a site characterization plan.


1.1 This guide refers to ASTM methods to perform site characterization for engineering, design, and construction purposes. The objective of the site characterization should be to identify and locate, both horizontally and vertically, significant soil and rock types and groundwater conditions present within a given site area and to establish the characteristics of the subsurface materials by sampling or in situ testing, or both.

1.2 Laboratory testing of soil, rock, and groundwater samples is specified by other ASTM standards not listed herein. Subsurface exploration for environmental purposes is also outside the scope of this guide.

1.3 Prior to commencement of the site characterization the site should be checked for potentially hazardous or otherwise contaminated materials or cultural/archeological conditions. If evidence of unknown potentially hazardous or otherwise contaminated materials or conditions are encountered in the course of the site characterization, work shall be interrupted until the circumstances have been evaluated and revised instructions issued.

1.3.1 In addition the location and nature of underground and overhead utilities should be identified to ensure that there is no impact to the proposed site characterization. Impacts may include but are not limited to interference with geophysical methods, damaging utilities, creating an unsafe work condition, and limiting accessibility for exploratory equipment.

1.4 The values stated in either SI units or inch-pound units are to be regarded as the standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. Inch-pound units are provided in brackets for convenience.

1.5 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word“ Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.

1.6 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.

1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.

1.8 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.

1.9 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.

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Book of Standards Volume: 04.08
Developed by Subcommittee: D18.01
Pages: 8
DOI: 10.1520/D0420-18
ICS Code: 93.020