In This Article We Covers Methods Of Tunneling In Rock Briefly,

Following Method Of Tunneling In Rock,

  • Drift Method
  • Heading And Benching Method
  • Full Face Method
  • Cantilever Car Dump Method
  • NATM Method

1) Drift Method

Drift Method Consist Driving Small Sized Heading, Centrally At Top Or Bottom Of Face, Which Later Enlarged By Widening And Benching.

This Method Suitable For Large Sized Tunnels In Difficult Or In Hard Rock.

Top Drift Method Is Popular And Involves Operation Like,

  • Boring And Blasting A Top Center Of Drift
  • Widening And Enlarging The Drift
  • Benching In Stages
Methods Of Tunneling In Rock By Drift

Drift Method Is One Of The Methods Of Tunneling In Rock.

Drift Method Also Know As Multiple Drift Method.

Advantages Of Drift Method

A Small Preliminary Section For The Full Length Has Been Accurately Driven, Which Economies Construction.

Elaborate Supporting Platforms Not Necessary For Drilling Openrations.

It Provides Good Ventilation For Workers.

Disadvantages Of Drift Method

The Enlargent Can Not Started Until Central Hole Constructed For Full Length.

Mucking Tracks Required To Shift Frequently, Bench to Bench.

This Method Extremely Costly.

2) Heading And Benching Method

This Method Involves The Drilling Of The Top Portion In Advance Of Bottom Portion.

If Rock Is Hard And Self Supporting, Then Top Heading Advances Ahead By One Round Over The Bottom, So That Heading And Benching Follow Each Other.

If Rocks Badly Broken, Then Top Heading Will Need Support And Bench Will Afford Platform For This, In Such Case Heading Is Excavated And Support To The Full Length Or Part Length Before Benching Started.

Heading Is Always Ahead Of Benching By Convenient Length And Formed By Excavating Full Width Above Spraining Line.

In One Blast One Heading And One Benching Are Blasted With Few Seconds Time Lag.

Heading And Benching Method Suitable For Soft Rock Tunneling Of Medium And Average Size.

Methods Of Tunneling In Rock By Heading And Bench

Advantages Of Heading And Benching Method

In This Method Drilling And Mucking Done Simultaneously.

Less Quantity Of Explosive Required As Compared To Full Face Method.

Disadvantages Of Heading And Benching Method

In Heading And Benching Method Removal Of Muck From Heading Is Difficult.

Heading And Benching Method Is One Of The Methods Of Tunneling In Rock.

3) Full Face Method

This Method Conveniently Adopted For Tunnels Of Small Cross Section Area Through Stable And Self Supporting Rocks And Whole Section Or Full Section Attacked At A Time.

Full Face Method Popular Due To Result Of Equipment Development.

At Present Techniques Shield And Tunnel Boring Machine (TBM) Are Popular And Well Suited For Full Face Excavation In Different Ground Condition And Various Shapes And Size.

Tunnel Boring Machine

This Method Useful When Diameter Less Than 6 m And Face Area Less Than 19 m2 As Further Increase In Diameter And Area Result In Difficult Construction And Costly.

This Method Of Tunnels Is Continuous.

Methods Of Tunneling In Rock By Full Face

Advantages Of Full Face Method

Simplicity As Minimum Equipment’s Required.

Minimize The Total Magnitude Of Ground Disturbance And Settlement.

Full Face Method Is Easily And Speedy Completion.

In Full Face Method Mucking Track Laid Once For Full Operation.

Full Face Method Is One Of The Methods Of Tunneling In Rock.

4) Cantilever Car Dump Method

This Method Provides And Improved Arrangement Of Throwing Muck From Bench To The Floor Of Tunnel.

Two Plate Girders About 23 m Length And 1.8 m Clear Cover Distance.

A Belt-Conveyor Fitted With No Of Jacks And Running On Plate Girders.

The Ends Of Plate Girders Project Beyond The Full Face Of The Bench And Front Ends Are Suitable, Supported By Means Of Struts From The Top Of Tunnel.

Cantilever Car Dump Method Is One Of The Methods Of Tunneling In Rock.

5) NATM Method

“NATM” Means New Austrian Tunneling Method, It Newly Developed Economical Tunneling Method In Rock.

This Method Used In Large Section In Very Difficult Grounds And Below Built Up Areas.

Also Used For Subway Construction And Abnormal Geological Conditions.

“NATM” Also Called Observational Method Or Shotcrete Method.

New Austrian Tunneling Method Is One Of The Methods Of Tunneling In Rock.

Methods Of Tunneling In Rock By NATM

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