ASTM D8359-21 PDF

Full title and description

Standard Test Method for Determining the In Situ Rock Deformation Modulus and Other Associated Rock Properties Using a Flexible Volumetric Dilatometer. Establishes procedures, equipment description, test execution, and analysis for using a flexible volumetric dilatometer in boreholes (N‑size, 75.7 mm / 2.98 in. nominal) to determine in situ deformation modulus and related rock‑mass properties.

Abstract

This test method (D8359‑21; DOI: 10.1520/D8359‑21) specifies the use of a flexible, volumetric dilatometer inflated and deflated hydraulically in a borehole to measure volume change and compute radial displacement and an in situ deformation modulus (Ed) for rock masses. The procedure covers equipment configuration, test setup in N‑size boreholes, measurement and calculation methods, reporting conventions (SI units preferred), and known limitations (averaged volumetric response, limited detection of anisotropy). The method is intended to produce engineering data for foundation, slope, tunnel, and underground works design and assessment.

General information

• Status: Active (current version D8359‑21).
• Publication date: August 24, 2021.
• Publisher: ASTM International.
• ICS / categories: 93.020 — Earthworks, excavations, foundation construction, underground works.
• Edition / version: D8359‑21 (2021).
• Number of pages: 19.

Scope

The standard provides guidelines, required equipment characteristics, test procedures, and analysis for determining the in situ deformation modulus of a rock mass using a flexible volumetric dilatometer placed in an N‑size (75.7 mm / 2.98 in. I.D.) borehole. It applies primarily to hydraulically inflated volumetric dilatometers but may be applied to other dilatometer types or borehole sizes at the project owner’s discretion. Cyclic/creep/unloading cycles are not covered in detail. The method yields an average radial deformation around the borehole and is intended for use in design, construction, and maintenance of structures on or in rock.

Key topics and requirements

• Equipment: a commercially available flexible volumetric dilatometer sized for N‑size (75.7 mm) boreholes; hydraulic inflation/deflation system and volume/pressure measurement capability.
• Test measurement principle: record dilatometer volume change with controlled inflation/deflation and compute radial displacement of borehole walls from total volume change; derive deformation modulus (Ed) from measured displacements and applied pressure.
• Standard test borehole and probe sizing: nominal N‑size, 75.7 mm (2.98 in.) I.D.; examples of effects from oversized holes and allowable maximum inflated diameter are specified.
• Examples of working pressures and limits: illustrative maximum working pressure and pressure‑diameter relations are provided (equipment dependent); users must avoid membrane damage and respect probe limits.
• Data quality and reporting: SI units are primary; significant digits and rounding per Practice D6026; reporting should include test conditions, probe geometry, pressure/volume records, and calculation assumptions.
• Assumptions and limitations: analyses generally assume linear elastic, homogeneous, isotropic behavior when taking Ed ≈ E for deformation analyses; volumetric test yields an averaged modulus and cannot by itself resolve directional anisotropy.
• Comparative and complementary methods: results may be correlated with plate loading, radial jack, flat jack and borehole jack tests; dilatometer testing is useful as a rapid, cost‑effective index of deformability prior to larger scale tests.
• Competence and safety: competence of personnel is critical (see Practice D3740); the standard does not supersede site‑specific health, safety, and environmental requirements.

Typical use and users

Used by geotechnical and rock mechanics engineers, engineering geologists, specialty testing contractors, consultants, and research groups to obtain in situ deformability data for foundation and slope design, underground excavations, dam foundations, piers and caissons, and feasibility studies. Commonly used where core specimens are limited or where rapid, in‑place index measurements of rock mass deformability are required.

Related standards

Relevant or referenced documents and comparable methods include EN ISO 22476‑5 (and other parts of the ISO 22476 field testing series), ISO/EN documents for dilatometer testing, ASTM Practice D3740 (competence of testing agencies), ASTM Practice D6026 (significant digits/rounding guidance), earlier version D8359‑20, and other in situ deformability tests such as radial jack tests, flat jack tests, flexible plate tests, and borehole jack tests.

Keywords

in situ deformation modulus; dilatometer; volumetric dilatometer; borehole testing; rock deformability; rock modulus; Ed; N‑size borehole; geotechnical field testing; ASTM D8359; rock mechanics.

FAQ

Q: What is this standard?

A: ASTM D8359‑21 is a standard test method that defines how to use a flexible volumetric dilatometer in boreholes to determine the in situ deformation modulus and related rock properties.

Q: What does it cover?

A: It covers equipment description, recommended borehole/probe sizing (N‑size, 75.7 mm), hydraulic inflation/deflation procedures, measurement and calculation of volume change and radial displacement, derivation of an in situ deformation modulus, reporting conventions (SI units preferred), and limitations of the method.

Q: Who typically uses it?

A: Geotechnical and rock mechanics engineers, engineering geologists, field testing contractors, and consultants who need in situ deformability data for design or investigation of foundations, slopes, tunnels, and other rock‑founded structures.

Q: Is it current or superseded?

A: Current as published in 2021 (designated D8359‑21). It replaces earlier versions (for example D8359‑20) and is listed as the active standard.

Q: Is it part of a series?

A: It is part of the suite of geotechnical field testing standards and relates to other field test standards (ISO/EN 22476 series for field testing, ISO flat dilatometer standards) and to ASTM practices for agency competence and data reporting.

Q: What are the key keywords?

A: Dilatometer, volumetric dilatometer, in situ deformation modulus, rock deformability, borehole testing, Ed, geotechnical field testing, N‑size borehole.