Significance and Use
5.1 Soundings performed using this test method provide a detailed record of dilatometer results, which are useful for evaluation of site stratigraphy, homogeneity, depth to firm layers, voids or cavities, and other discontinuities. The penetration resistance, if obtained, and subsequent membrane expansion are used for soil classification and correlation with the engineering properties of soils.
5.2 The DMT may provide measurements of penetration resistance, lateral stress, deformation modulus, and pore-water pressure (in sands). However, the in-situ soil properties are affected by the penetration of the blade. Therefore, published correlations are used to estimate soil properties for the design and construction of earthworks and foundations for structures, and to predict the behavior of soils subjected to static or dynamic loads.
5.3 This test method tests the soil in-situ and soil samples are not obtained. However, the interpretation of the results from this test method does provide an estimate of the types of soil penetrated. Soil samples from parallel borings may be obtained for correlation purposes, but prior information or experience may preclude the need for borings.
NOTE 2: The quality of the result produced by this test method is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/ inspection/etc. Users of this test method are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
Scope
1.1 This test method describes an in-situ penetration plus expansion test. The test is initiated by forcing the steel, flat plate, dilatometer blade2, with its sharp cutting edge, into a soil. Each test consists of an increment of penetration, generally vertical, followed by the expansion of a flat, circular, metallic membrane into the surrounding soil. The test provides information about the soil’s in-situ stratigraphy, stress, strength, compressibility, and pore-water pressure for use in the design of earthworks and foundations.
1.2 This method includes specific requirements for the preliminary reduction of dilatometer test data. It does not specify how to assess or use soil properties for engineering design.
1.3 This method applies best to those sands, silts, clays, and organic soils that can be readily penetrated with the dilatometer blade, preferably using static push (see 4.2). Test results for soils containing primarily gravel-sized particles and larger may not be useful without additional research.
1.4 This method is not applicable to soils that cannot be penetrated by the dilatometer2 blade without causing significant damage to the blade or its membrane.
1.5 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes shall not be considered as requirements of the standard. The illustrations included in this standard are intended only for explanatory or advisory use
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method
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 and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally 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 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 ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
1.10 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 and health practices and determine the applicability of regulatory limitations prior to use.
