Standards Development

Scope

This committee standardises the civil and structural design of tunnels and associated underground structures in soil and rock where they are integral to tunnel infrastructure. It covers tunnel-specific design interfaces including geotechnical design inputs, groundwater design actions and responses, ground reinforcement, structural linings, durability, ground-structure interaction, and the assessment and retrofitting of existing tunnels. Special cases such as immersed tunnels, cross passages forming part of tunnel systems, and underground stations may be considered only where the work concerns tunnel-specific civil and structural design and does not duplicate the remit of existing ISO or IEC committees. The committee is intended to provide a coherent framework for tunnel infrastructure performance, safety, durability, resilience and functionality, while recognising applicable existing standards for materials, systems, operations and environmental matters.

Excluded: groundwater monitoring methods, hydrogeological investigation methods, groundwater data acquisition and interpretation (ISO/TC 113/SC 8); air quality criteria, pollutant assessment, air velocity sensors, ventilation system design, fan dimensioning and ventilation equipment (including ISO/TC 146/SC 3 and ISO/TC 117); fire safety systems, life safety systems, emergency communication systems and railway-specific safety requirements or installations, including aerodynamics, overhead-line equipment, alarm systems and emergency systems (including relevant ISO/IEC committees and ISO/TC 269/SC 1 where applicable); road traffic safety management, traffic operations and traffic-control systems (including ISO/TC 241 where applicable); tunnel lighting and light sources (including ISO/TC 274 and relevant CEN work); product, material and execution standards for concrete, sprayed concrete, injection products, geosynthetics, waterproofing and drainage products (including ISO/TC 71 and ISO/TC 221); building and civil engineering information management/BIM, digital-twin information management and sustainability assessment methods as general cross-cutting subjects (including ISO/TC 59/SC 13 and ISO/TC 59/SC 17); environmental management and environmental impact assessments (including ISO/TC 71/SC 8 and relevant existing committees); hydraulic tunnels; above-ground structures; standalone underground utilities; building architecture and finishes; electrical and communication systems; mining excavations; machinery and equipment design; and non-transport underground works.

Purpose

There is currently no ISO committee responsible for the standardisation of civil and structural tunnel design as an integrated underground infrastructure topic. Worldwide, tunnel projects rely on a mixture of structural codes, geotechnical standards, national tunnelling guidelines, and project-specific “Deemed-to-Satisfy” criteria. This leads to inconsistent approaches to tunnel-specific design interfaces, challenges in comparing performance across jurisdictions, and difficulties in ensuring long-term safety, durability, resilience and efficiency across the lifecycle of underground infrastructure.

Internationally, tunnel design practice is mature but fragmented. Regions such as Europe, East Asia and North America apply different frameworks, including DAUB recommendations (Germany), Japanese Road Association tunnel standards, Chinese highway and railway tunnel standards, UK BD 78/99 and BS 6164, the FHWA highway tunnel guidance and DCRT-1-2010 (USA), PIARC Road Tunnel Manual, and relevant Eurocodes. These references provide substantial experience but are not harmonised globally or fully aligned with ISO committee structures. Recent major projects, including the Tianshan Shengli Tunnel, the Hong Kong-Zhuhai-Macao Bridge, the Shenzhen-Zhongshan Link, the Ryfylke Tunnel and the Ceneri Base Tunnel, further demonstrate the scale, diversity and international relevance of tunnel design practice.

This proposed Technical Committee will focus on tunnel-specific civil, structural and geotechnical design interfaces rather than product, system, operational or environmental standards. It will coordinate with, but not duplicate, existing ISO and IEC committees responsible for related subject areas, including concrete and material/product standards, groundwater methods, ventilation and fans, fire and life safety systems, lighting, railway-specific systems, road traffic safety, digital information management and sustainability assessment.

The increasing scale and complexity of underground construction highlight the need for consistent design principles governing the structural and geotechnical performance of tunnels, while respecting established national and regional requirements. The proposed work is not intended to replace national codes or prescribe a single global calculation method. Instead, it is intended to provide common terminology, performance principles, design interfaces and coordination guidance for tunnel-specific civil and structural design, supporting consistency where international projects must rely on multiple codes and project specifications.

A new ISO technical committee would:

• Establish consistent international principles for tunnel-specific civil and structural design, including geotechnical characterisation, actions and load combinations, ground-structure interaction, durability, lifecycle performance and resilience.

• Address design interfaces not coherently covered in existing ISO standards, such as segmental lining behaviour as a structural system, observational design, ground improvement interfaces, groundwater design actions, waterproofing/drainage as design interfaces, retrofit of existing tunnels and long-term asset performance.

• Promote harmonisation across national and regional guidelines without replacing jurisdictional legal requirements, thereby reducing duplication of effort and lowering barriers for cross-border engineering practice.

• Support lifecycle- and performance-based tunnel design while coordinating with relevant ISO, IEC, CEN and professional bodies on adjacent subjects that remain outside the scope of the proposed TC.

Establishing this new field of technical activity will benefit countries with major tunnelling programmes - including China, Japan, Germany, South Korea, Austria, the United Kingdom, the United States, India, Australia, Norway, Switzerland and Singapore - while supporting equitable access to consistent standards for developing markets. It will also support high-reliability and climate-resilient underground infrastructure.