1. Scope

1.1 The flatjack test measures stress at a rock surface. The modulus of deformation and the long-term deformational properties (creep) may also be evaluated.

1.2 Limitation -The flatjack test measures stresses only at the surface of the test chamber. Undisturbed stress levels must be determined by theoretical interpretations of these data.

1.3 Assumptions and Factors Influencing the Data:

1.3.1 The stress relief is assumed to be an elastic, reversible process. In nonhomogeneous or highly fractured materials, this may not be completely true.

1.3.2 The equations assume that the rock mass is isotropic and homogeneous. Anisotropic effects may be estimated by testing in different orientations.

1.3.3 The flatjack is assumed to be 100% efficient. The design and size requirements of 5.1 were determined to satisfy this requirement to within a few percent.

1.3.4 The jack is assumed to be aligned with the principal stresses on the surface of the opening. Shear stresses are not canceled by jack pressure. Orientating the tests in three directions in each plane tested prevents the misalignment from being excessive for at least one of the tests.

1.4 The values stated in inch-pound units are to be regarded as the standard.

1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D653 Terminology Relating to Soil, Rock, and Contained Fluids

D2113 Practice for Rock Core Drilling and Sampling of Rock for Site Investigation

D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction

D5720 Practice for Static Calibration of Electronic Transducer-Based Pressure Measurement Systems for Geotechnical Purposes

D6026 Practice for Using Significant Digits in Geotechnical Data

D6027 Practice for Calibrating Linear Displacement Transducers for Geotechnical Purposes

Keywords

creep; flatjack hydraulic pressure; in situ stress; modulus of deformation; Deformation--rock; Drilling (in soil/rock); Field testing--rock; Flatjack method; Gages; Isotropic rock specimens; Modulus--soil/rock applications; Rock materials/properties/analysis; Stress--rock; Surface preparation; Transducers; Underground environments;

ICS Code

ICS Number Code 93.020 (Earth works. Excavations. Foundation construction. Underground works)

DOI: 10.1520/D4729-87R97

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