【国外标准】 Standard Test Methods for Measuring the Depth of Deep Foundations by Parallel Seismic Logging

5.1 It is often necessary to determine the depth of deep foundation elements supporting existing structures, such as buildings and bridges, for which neither drawings nor as-built records are available. Such situations occur when the foundation loads have to be increased or when it is intended to excavate near, or even under, the structure. When the top of the foundation is inaccessible, as is the case with underwater bridge piers, the Parallel Seismic method can be used to determine the deep foundations’ depth. The method is also applicable in cases where the foundation top can be reached, but the foundation element is not testable by the Low Strain Impact Integrity Testing Method (ASTM D5882) due to the foundation type (such as diaphragm and secant-pile walls, H-piles and sheet piles) or excessive foundation slenderness.5.2 Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing and inspection. However, users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results since the proper conduct and evaluation of parallel seismic tests requires training, special knowledge and experience. A suitably qualified engineer shall plan and supervise the acquisition of field data and the interpretation of the test results.1.1 The test Methods described in this standard are used to measure the depth of vertical deep foundation elements including micropiles, driven piles (prefabricated or cast in-situ), bored piles, secant or tangent pile walls, caissons, barrettes, diaphragm walls and sheet pile walls. It is applicable where the top of the said foundation element (in the following also named “pile”) cannot be exposed for testing and other testing methods such as ASTM D5882 or D6760 cannot be used.1.2 This standard provides minimum requirements for measuring the depth of deep foundations. Plans, specifications, and/or provisions may provide additional requirements and methods as needed to satisfy the objectives of a particular test program.1.3 This standard provides the following test methods:1.3.1 Method “A” using a vertical access tube adjacent to the deep foundation.1.3.2 Method “B” using a seismic cone inserted into the ground adjacent to the deep foundation.1.4 Apparati and Methods herein designated “optional” may produce different a different kind of test results or additional information and may be used only when approved by the engineer responsible for the test.1.5 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.1.6 Units—The values stated in either SI units or inch-pound units are to be regarded separately as 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.1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.8 The methods 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 methods 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.1.9 This standard 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 standard may be applicable under 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 only means that the document has been approved through the ASTM consensus process.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.11 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.