T/CCTAS 227-2025 Design Specification for Extra-Large Span Rock Tunnels

Scope

Main technical content: In recent years, the demand for building larger span (30m~70m) underground storage facilities (tunnels) in China has gradually increased. With the increase in excavation span, the stress state and failure mechanism of underground tunnels will undergo qualitative changes. Existing design codes cannot meet the construction needs. This standard, combined with the successful experience of existing 30m-70m underground tunnels, formulates relevant design procedures. This standard specifies the basic provisions for the design of super-large span rock tunnels, engineering investigation, scheme design, surrounding rock stability analysis, support design, waterproofing and drainage, excavation design, monitoring and measurement, etc. It is applicable to new super-large span rock tunnels with a single span of 30m to 70m.

Development Information

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