This standard prescribes safety measures for tunnelling operations in soft ground conditions. It covers essential precautions for excavation, temporary supports (shoring/timbering), ventilation, gas monitoring, and dewatering to prevent cave-ins and ensure worker safety.
Lays down safety requirements for tunnelling operations specifically in soft ground, covering methods, ground stabilization, and support.
Quick Reference Values
minimum ventilation rate6 m³/min per person
max permissible methane concentration1.25%
max voltage for portable lighting24 V
minimum illumination at working face50 Lux
Practical Notes
Ensure immediate installation of temporary supports (timbering or steel ribs) right after excavation to prevent sudden face collapse.
Continuous monitoring for ground settlement and toxic/explosive gases is mandatory in soft soil strata.
Dewatering must be carefully managed to avoid excessive surface subsidence or instability of adjacent structures.