Method of Tunneling

Method of Tunneling

  1. Fore-Poling Method
  • Ancient method, used for running ground.
  • Now replace by compressed air tunneling method
  • Slow, tedious method but safe.
  • Skilled labors and strict provision required.


  1. Needle Beam Method
  • Suitable for firm ground.
  • Needle beam consist of a stout timber beam from main temporary support.
  • Roof of this drift is lagged with sheeting.
  • With help of jacks, drift is widened sideways.


  1. Belgian Method
  • It is used moderately firm or hard soils.
  • Heading is widened sideways, and supported by additional crown bars on sill.
  • Inserted the shore at side and excavate the mop.


  1. Austrian Method
  • It is also known as “sequential excavation method”.
  • A center cut is taken for full height.
  • Cut is widened to full face.
  • Permit short section of masonry to be completed.


  1. American Method
  • It is used for railway or highway tunneling.
  • Walls plates are introduced at the springing supporting the arch set.
  • Side is widened.


  1. English Method
  • The main characteristics of this method is excavation of full section of the tunnel at once using longitudinal strutting and alternate of masonry work and excavation.
  • It is supported on crown bars.
  • Then started excavation of part-2 and put the sill.


  1. Army Method or Case Method
  • It is derived by USA army for constructing small tunnels at shallow depth.
  • A top braced is removed and ground is excavated for a short distance.
  • The box is moved ahead and set next cap.


  1. German Method
  • In this method 3 drifts are used to support the roof and side.
  • One at the crown and rest two are at bottom along the wall.


  1. Shield Method
  • It is used for driving a tunnel through water bearing strata.
  • It is equipment which acts as a bridge with roof for workers.
  • A shield is a movable frame and it is used to support the face of the tunnel.


  1. Compressed Air Method
  • Most modern method used for tunneling in soft grounds having water bearing strata.
  • Timber support is not required.
  • Support is provided by compressed air into enclosed space to prevent the collapse of roof and sides of tunnel.


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