NATM / CONVENTIONAL TUNNELLING
Conventional tunnels are typically constructed with the New Austrian Tunnelling Method (NATM), Norwegian Tunnelling Method (NTM), or the Sprayed Concrete Lining (SCL) Method. During Tunneling, different rock shapes, soil and rock conditions, and unknown geological structures can throw up challenges. Engineers must also deal with high groundwater pressure, geothermal gradients, squeezing fault zones, alignment, and high in situ stress. Such tunnels can pass through varying ground conditions—somewhere intensely jointed zones and somewhere soft ground conditions.
The uncertainties associated with designing deep tunnels require a clear understanding of tunnel types, tunnel behavior, and failure modes. Careful analysis, assessment, and risk mitigation measures are the key to successfully executing such projects in difficult terrains.
Bouw’s expertise lies in evaluation of all the aspects of deep tunnels and preparing flexible, cost-effective designs with due consideration to the non-linearity in material behavior.
ACTIVITIES
- Alignment selection
- Excavation Sequences / Construction Methods
- Primary / Secondary Lining Design (with or without reinforcement, steel fiber)
- Tunnel Portal Design
- Rock Bolt Support with Shotcrete
- Design of ground improvement requirements
- MEP & Ventilation Design
- Instrumentation & Monitoring Plan & Specifications
- Assessment of recorded data and advice further action