ISO 18674-5:2019
Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation — Part 5: Stress change measurements by total pressure cells (TPC)
Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation — Part 5: Stress change measurements by total pressure cells (TPC)
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 27
- Дата публикации:
- 10 октября 2019 г.
- Издание:
- ISO IS 18674 edition 1 version 1
- ICS:
- 13.080.20
This document specifies the measurement of stress changes by means of total pressure cells (TPC). General rules of performance monitoring of the ground, of structures interacting with the ground, of geotechnical fills and of geotechnical works are presented in ISO 18674‑1. If applied in conjunction with ISO 18674‑4, this document allows the determination of effective stress acting in the ground. This document is applicable to: — monitoring changes of the state of stress in the ground and in geo-engineered structures (e.g. in earth fill dams or tunnel lining); — monitoring contact pressures at the interface between two media (e.g. earth pressure on retaining wall; contact pressure at the base of a foundation); — checking geotechnical designs and adjustment of construction in connection with the Observational Design procedure; — evaluating stability during or after construction. Guidelines for the application of TPC in geotechnical engineering are presented in Annex B. NOTE This document fulfils the requirements for the performance monitoring of the ground, of structures interacting with the ground and of geotechnical works by the means of total pressure cells as part of the geotechnical investigation and testing according to EN 1997-1[1] and EN 1997-2[2].
Abstract
Overview
ISO 18674-5:2019 specifies how to measure changes in stress in the ground and geotechnical structures using total pressure cells (TPC). It defines instrument types, installation and measuring procedures, data processing and reporting requirements for stress-change monitoring. When used together with ISO 18674-4 (piezometers) the standard supports determination of effective stress in saturated ground. ISO 18674-5 is intended for performance monitoring of ground, geotechnical fills and structures interacting with the ground (e.g., earth dams, retaining walls, foundations, tunnel linings).
Key technical topics and requirements
- Scope of measurement:
- Measurement of total normal stress changes (Δσn) acting on the sensing face of a TPC.
- Monitoring contact pressures at interfaces (e.g., foundation base, retaining-wall face).
- Limitations: TPCs measure normal stress only; shear stresses are not measurable.
- Instrument components and types:
- Typical system: pressure compartment, pressure tubing, pressure-measuring device, measuring line and readout unit.
- TPC variants: embedment pressure cells, contact pressure cells, borehole pressure cells; specialized radial and tangential cells for tunnels.
- Design considerations: aspect ratio (typical 1:20 to 1:40), stiffness of pressure compartment, shape and accuracy.
- Measuring methods:
- Deformation measuring method vs compensation measuring method - trade-offs in stability, stiffness, long-term reliability, and installation complexity.
- Installation, calibration and procedure:
- Detailed guidance for installation in ground, fills, concrete/shotcrete and contact planes.
- Instrumentation checks, calibration, and barometric/temperature compensation requirements.
- Data handling and reporting:
- Procedures for data processing, evaluation and required content for installation and monitoring reports.
- Normative Annex A (evaluation procedure) and informative Annexes B/C with applications and measuring examples.
- Error sources and mitigation:
- Presence of the TPC alters the local stress field (registering effects); correct instrument selection and installation reduce bias.
- Cluster measurements:
- One compartment measures a single stress component; clusters (3 compartments for 2-D, 6 for 3-D) are required for full stress-state monitoring.
Practical applications
ISO 18674-5 is applicable to:
- Monitoring stress changes in earth fill dams, embankments and foundations.
- Tunnel lining monitoring (radial/tangential stress measurement).
- Retaining-wall and contact pressure monitoring.
- Observational Design procedures to check and adjust geotechnical construction.
- Stability evaluation during and after construction.
Who should use this standard
- Geotechnical engineers and consultants
- Instrumentation suppliers and field technicians
- Tunnel and dam design/construction teams
- Structural and foundation engineers involved in monitoring and performance verification
- Regulators and reviewers referencing EN 1997 compliance
Related standards
- ISO 18674-1 (General rules for geotechnical monitoring)
- ISO 18674-4 (Piezometers - pore water pressure measurement)
- EN 1997-1 and EN 1997-2 (Geotechnical design and investigation)
Технические детали
- Технический комитет
- ISO/TC 182 - Geotechnics
- SKU
- ISO 18674-5:2019
Похожие стандарты
Стандарты, упомянутые в описании