【国外标准】 Standard Test Method for Approximating the Shear Strength of Cohesive Soils by the Handheld Vane Shear Device

5.1 The handheld shear vane method provides a rapid method of measuring the approximate undrained shear strength of a fine-grained, cohesive soil either in the field or laboratory. This standard does not supplement or replace D4648.5.2 The device is intended for use in saturated cohesive soils for determining their approximate undrained shear strength. Cohesive soils with appreciable amounts of silt or fine sand may experience some degree of drainage during shear and adversely affect the results.NOTE 2: The user will probably not know at the time of testing if the material is saturated. However, that would not preclude using the device for less than saturated conditions based on the knowledge and experience of the user.5.3 The presence of coarse materials or heterogeneous soils within the testing volume will adversely affect the results and may preclude the use of this test method.5.4 The handheld shear vane test is not used to duplicate any particular field conditions but supplements the overall investigative program. However, consistent physical parameters are used in the test such that correlations of shear strength data can be made to evaluate variability of a deposit, assess sample quality, assist in planning of laboratory testing programs, and to classify the consistency.NOTE 3: The quality of the result produced by this standard 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 standard 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.1.1 This test method describes approximating the shear strength of cohesive soils using a handheld (pocket) vane shear device.1.2 The device allows for a simple and portable method for measuring the approximate undrained shear strength of saturated, fine-grained, cohesive soils. The test method can be used in the field or in the laboratory, on the ends of sample tubes, on the surface of block samples or excavations, or on the surface of other test specimens with rigid confinement.1.3 Units—The values stated in either inch-pound units or SI units [given in brackets] 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. Tables of critical dimensions and tolerances of the described vanes are provided in separate units of inches and mm.NOTE 1: The original shear vane device was developed when shear strength was often reported in tons per square foot (TSF) or kilograms per square centimeter (kg/cm2) which are approximately equivalent. These units have prevailed within the industry and are adopted herein.1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.1.4.1 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 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 test method to consider significant digits used in analysis methods for engineering design.1.5 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.1.6 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.