1.1 本试验方法定义了使用恒定速率的简单剪切变形加载模式测量一维固结后细粒土的恒定体积强度和应力-应变特性的设备规范和试验程序。恒定体积条件相当于饱和试样的不排水条件。 1.2 本试验方法专为测试长方体或圆柱形试样的设备而编写。其他更通用的装置，如扭转剪切空心圆柱体，可用于进行固结恒体积简单剪切试验，但不在本试验方法的范围内。 1.3 本试验方法适用于测试完整、实验室复原和压实的土壤，但不包括复原或压实试样的具体指导。 1.4 要求进行此试验的机构应负责指定恒定体积剪切前的垂直固结应力的大小，并在适当的情况下指定将导致试样过度固结的最大垂直固结应力。 1.5 单位-- 以国际单位制表示的值应被视为标准。 本标准不包括其他计量单位。以国际单位制以外的单位报告测试结果不应被视为不符合本标准。 1.5.1 在工程领域，通常的做法是交替使用表示质量和力的单位，除非涉及动态计算（F=Ma）。这隐含地结合了两个独立的单位系统，即绝对系统和重力系统。在科学上，将两个独立的系统结合在一个标准中是不可取的。 本试验方法采用国际单位制编写；然而，英寸-磅转换是在重量分析系统中给出的，其中磅（lbf）表示力（重量）的单位。使用天平或磅秤记录质量磅（lbm），或以lb/ft为单位记录密度 3. 不应被视为不符合本试验方法。 1.6 所有观察值和计算值应符合《规程》中规定的有效数字和四舍五入的准则 D6026 . 1.6.1 本测试标准中用于指定如何收集/记录或计算数据的程序被视为行业标准。 此外，它们代表了通常应保留的有效数字。所使用的程序不考虑材料变化、获取数据的目的、特殊目的研究或对用户目标的任何考虑；通常的做法是增加或减少报告数据的有效数字，以与这些考虑因素相称。考虑工程设计分析方法中使用的有效数字超出了本测试标准的范围。 1.6.2 测量到比本标准规定更高的有效数字或更高的灵敏度不应被视为不符合本标准。 1.7 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 =====意义和用途====== 5.1 试样的抗剪强度取决于剪切方法、土壤类型、垂直固结应力、固结时间、应变率和土壤的先前应力历史。 5.2 在该试验中，剪切强度是在恒定体积条件下测量的，该条件相当于饱和试样的不排水条件；因此，该试验适用于土壤在一组应力下完全固结，然后在没有时间进行进一步排水的情况下受到应力变化的现场条件。 5.3 恒定体积（不排水）强度是应力条件的函数。在该试验方法中，强度是在平面应变条件下测量的，并且由于施加剪切应力，主应力持续旋转。这种简单的剪应力条件发生在许多现场情况下，包括长路堤下方和轴向加载桩周围的区域。 5.4 简单剪切试样内的应力状态不够明确，也不够均匀，无法对结果进行严格解释。 以水平面上的剪应力和垂直有效应力表示数据对于工程目的很有用，但不应与从具有更好应力状态的其他剪切试验中得出的有效应力参数混淆。 5.5 本试验固结部分的数据和固结率与使用试验方法获得的结果相当 D2435/D2435米 前提是测试方法的更严格的整合程序 D2435/D2435米 遵循。 5.5.1 当使用钢丝增强膜时，根据试验方法测量的垂直位移 D2435/D2435米 比直接单剪试验稍小，因为直接单剪（DSS）试样的横向约束刚性较小。 5.5.2 估算的前期固结压力与试验方法中的压力相当 D2435/D2435米 ，前提是试样被充分加载到正常固结范围内。

1.1 This test method defines equipment specifications and testing procedures for the measurement of constant volume strength and stress-strain characteristics of fine-grained soils after one-dimensional consolidation, using a constant rate of simple shear deformation mode of loading. The constant volume condition is equivalent to the undrained condition for saturated specimens. 1.2 This test method is written specifically for devices that test rectangular parallelepiped or cylindrical specimens. Other more general devices, such as the torsional shear hollow cylinder, may be used to perform consolidated constant volume simple shear tests but are beyond the scope of this test method. 1.3 This test method is applicable to testing intact, laboratory reconstituted, and compacted soils, however, it does not include specific guidance for reconstituting or compacting test specimens. 1.4 It shall be the responsibility of the agency requesting this test to specify the magnitude of the vertical consolidation stress prior to constant volume shear and, when appropriate, the maximum vertical consolidation stress, which will result in an overconsolidated specimen. 1.5 Units— The values stated in SI units are to be regarded as the standard. No other units of measure are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 1.5.1 In the engineering profession it is customary practice to use, interchangeably, units representing both mass and force, unless dynamic calculations (F=Ma) are involved. This implicitly combines two separate systems of units, that is, the absolute system and the gravimetric system. It is scientifically undesirable to combine two separate systems within a single standard. This test method has been written using SI units; however, inch-pound conversions are given in the gravimetric system, where the pound (lbf) represents a unit of force (weight). The use of balances or scales recording pounds of mass (lbm), or the recording of density in lb/ft 3 should not be regarded as nonconformance with this test method. 1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 . 1.6.1 The procedures used to specify how data are collected/recorded or calculated in this test 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; 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 standard to consider significant digits used in analysis methods for engineering design. 1.6.2 Measurements made to more significant digits or better sensitivity than specified in this standard shall not be regarded a nonconformance with this standard. 1.7 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. 1.8 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. ====== Significance And Use ====== 5.1 The shear strength of a specimen depends on the method of shearing, soil type, vertical consolidation stress, time of consolidation, rate of strain, and prior stress history of the soil. 5.2 In this test, the shear strength is measured under constant volume conditions that are equivalent to undrained conditions for a saturated specimen; hence, the test is applicable to field conditions wherein soils have fully consolidated under one set of stresses, and then are subjected to changes in stress without time for further drainage to take place. 5.3 The constant volume (undrained) strength is a function of stress conditions. In this test method, the strength is measured under plane strain conditions and the principle stresses continuously rotate due to the application of shear stress. This simple shear stress condition occurs in many field situations including zones below a long embankment and around axially loaded piles. 5.4 The state of stress within the simple shear specimen is not sufficiently defined nor uniform enough to allow rigorous interpretation of the results. Expressing the data in terms of the shear stress and vertical effective stress on the horizontal plane is useful for engineering purposes, but should not be confused with the effective stress parameters derived from other shear tests having better defined states of stress. 5.5 The data and the rate of consolidation from the consolidation portion of this test are comparable to results obtained using Test Methods D2435/D2435M provided that the more rigorous consolidation procedure of Test Methods D2435/D2435M is followed. 5.5.1 When using wire reinforced membranes the vertical displacements measured from Test Methods D2435/D2435M are somewhat smaller than for the direct simple shear test because the direct simple shear (DSS) specimen's lateral confinement is less rigid. 5.5.2 The estimated preconsolidation pressure is comparable to that from Test Methods D2435/D2435M , provided the specimen is loaded sufficiently into the normally consolidated range.