1.1 本指南提供了沉降点的制造、安装、操作和读数的建议设计和程序，以确定在填土或路堤荷载下基础、填土沉降或两者的大小和速率。本文描述了两种类型的沉降点——通过外部基准点的高程测量进行监测的沉降点和包括内部参考系统的沉降点，内部参考系统支撑在相关可压缩层下方的不屈服土壤或岩石上。 1.2 单位- 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本指南提供了有组织的信息收集或一系列选项，并不推荐具体的行动方案。本文件不能取代教育或经验，应与专业判断结合使用。 并非本指南的所有方面都适用于所有情况。本ASTM标准不代表或取代必须根据其判断给定专业服务的充分性的谨慎标准，也不应在不考虑项目的许多独特方面的情况下应用本文件。本文件标题中的“标准”一词仅表示该文件已通过ASTM共识程序获得批准。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 填土通常作为工程结构建造，例如大坝，或用于支撑工程结构，例如道路或建筑物。填料的重量可能会压缩或变形支撑土壤或岩石基础，导致整个路堤和路堤下方的土壤沉降。在实际基础或结构放置之前，修建临时路堤或堆载填土，以增加地基土的强度和/或降低其压缩性。设计人员经常监测土结构的沉降，作为时间的函数，以记录沉降的幅度和速率，评估未来沉降的可能性，或确认超载的有效性及其移除时间表。使用路堤施工之前或期间安装的沉降点进行监测。 沉降点提供了一个可接近的测量点，该测量点与路堤内或路堤下方的选定土层沉降。仔细设计和安装沉降点可以将测量点与外部运动源隔离开来，例如冻胀、路堤内的压缩或水分增加或损失引起的体积变化。 5.2 使用它们的机构和从业者开发了各种安置点设计。本标准指南提供了设计指南、规范和报告中可参考的设计和程序。 5.3 本标准指南并不旨在限制使用其他同样合适的设计和程序来制造、安装、操作和读取沉降点，以监测施工期间和之后土壤沉积物中的变形。 注2: 尽管本指南中包含精度和偏差声明，但本指南的精度取决于执行指南的人员的能力以及所用设备和设施的适用性。 符合实践标准的机构 D3740 通常认为能够胜任和客观测试。本指南的用户应注意遵守惯例 D3740 本身不能确保可靠的测试。可靠的测试取决于许多因素；实践 D3740 提供了一种评估其中一些因素的方法。

1.1 This guide provides recommended designs and procedures for the fabrication, installation, operation, and reading of settlement point(s) to determine the magnitude and rate of foundation, fill settlements, or both generally under a fill or embankment load. Two types of settlement points are described – those being monitored by elevation surveys from an external bench mark and those that include an internal reference system supported on unyielding soil or rock beneath the compressible layer(s) of interest. 1.2 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This guide 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 judgement. Not all aspects of this guide may be applicable in 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 means only that the document has been approved through the ASTM consensus process. 1.4 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. 1.5 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 Earthen fills are often constructed as engineered structures, for example, dams, or to support engineered structures, for examples, roads or buildings. The weight of the fill may compress or deform the supporting soil or rock foundation resulting in settlement of the soil throughout and beneath the embankment. Temporary embankments or surcharge fills are constructed to increase the strength and/or reduce the compressibility of foundation soils prior to placement of the actual foundation or structure. The designers often monitor the settlement of the earth structure as a function of time to document the magnitude and rate of settlement, to evaluate the potential for future settlement, or to confirm the effectiveness of the surcharge and the schedule for its removal. The monitoring is performed using settlement points installed prior to or during the embankment construction. A settlement point provides an accessible survey point that settles with a selected soil horizon within or below the embankment. Careful design and installation of the settlement point can isolate the survey point from extraneous sources of movement such as frost-induced heave, compression within the embankment, or volume changes caused by moisture gain or loss. 5.2 Various settlement point designs have been developed by the agencies and practitioners that use them. This standard guide provides designs and procedures that can be referred to in design guidelines, specifications and reports. 5.3 This standard guide is not meant to restrict the use of other equally appropriate designs and procedures for the fabrication, installation, operation, and reading of settlement points to monitor deformations in earthen deposits during and after construction. Note 2: Notwithstanding the statements on precision and bias contained in this guide, the precision of this guide 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. Users of this guide are cautioned that compliance with Practice D3740 does not itself ensure reliable testing. Reliable testing depends on many factors; Practice D3740 provides a means of evaluating some of these factors.