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Tunnels and tunneling (Engineering Geology)

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SudhanKumarSubedi

- The document provides information about tunnels and tunneling, including background on some of the earliest tunnels constructed by ancient Egyptians and Babylonians. - Tunnels can be classified based on their purpose, geological location/condition, and cross-sectional shape. Examples of different tunnel types and shapes are given. - Key geological conditions that influence tunnel planning and construction are discussed, including rock properties, groundwater conditions, and fault zones. The importance of site investigations is emphasized. - Methods of tunnel construction in soft ground, dealing with water and gases in tunnels, and controlling temperature are outlined. Excavation methods like cut-and-cover, sequential excavation (drill-and-blast), and tunnel boring

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Tunnels and Tunneling Date : May 23, 2020 Time : 1 : 00 P.M. Especially for course of B.Sc. Fourth Year ENGINEERING GEOLOGY Presenter : Sudhan Kumar Subedi Meeting ID : 797 0719 4445 Meeting Password : 8CswQY Interested can Join Zoom Meeting https://us04web.zoom.us/j/79707194445?pwd=VHIxQU0rSGgvbWlvOUd1K2xaN2t6dz09 Basics on
Tunnels and tunneling (Engineering Geology)
Tunnels and tunneling (Engineering Geology)
May 23, 2020 Tunnels and Tunneling Background  It is understood that first tunnel was constructed by Egyptians and Babylon's about 4000 years ago. This tunnel length – 910 m . width – 360 cm height – 450 cm  Tunnels may be defined as the underground passages or routes excavated through the rocks or soft ground without disturbing the overlaying rocks or soil covers.  In Hindu Religion, in Mahabharat time, during Dwaparyuga, Pandavas get escaped through Tunnel in Lakshagriha for being safe from fire burned by Duryodhan (Kauravs).
May 23, 2020 Tunnels and Tunneling Background According to local, About 250 years ago, Our ancestors used to excavate the tunnels for the mining activities for making the coins in this area. Due to the huge over breakage of rock during the excavation, 9 peoples died on site and then it has been closed.
May 23, 2020 Tunnels and Tunneling Background  Tunnels are very important structures which are being used in various construction ; like in hydropower project, mining activities, roads, railway for defence purpose and laying of pipelines etc. Classified by Examples of Tunnels Purpose Railway tunnels, metro system, highway tunnels, pedestrian tunnels, water tunnels, sewage tunnels, services tunnels, storage tunnels Geological location/ condition Rock tunnels, earth tunnels, submerged tunnels Cross-sectional shapes Rectangular shape, circular shape, elliptical shape, egg shape, horse-shoe shape and segmental shape  Tunnels can be classified on the different basis as :
May 23, 2020 Tunnels and Tunneling Background  Tunnels have different shapes on the basis of their uses and the ground conditions and the availability of materials.
May 23, 2020 Tunnels and Tunneling Background Hydropower Tunnel Hydropower Tunnel
May 23, 2020 Tunnels and Tunneling Background Road Tunnel Railway Tunnel
May 23, 2020 Tunnels and Tunneling Background Silver Mine Tunnel Copper Mine Tunnel
May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  Tunneling is a serious engineering project.  In addition to large investment cost, the challenges related to long and deep tunnels are the site characteristics along the alignment routes.  Geology plays a very important role in this. Any adverse and unforeseen geological conditions may influence the safety of tunnels, loss of life, construction time and costs.  When a tunnel or shaft is excavated, the rock stresses are perturbed around the opening and displacements will occur.
May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling
May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  The physical context and key constraints that influence the planning of a tunnel alignment within the project corridor are : • geology; • water courses; • utilities; • historic structures; and • land use.  The site geology provides the background setting for any underground engineering structure.  The mechanical properties of the rock describe how the geologic materials deform and fail under the forces introduced by the excavation.  The geohydrologic conditions establish the quantity and pressure of water that must be controlled.
May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  Geological/ geotechnical investigations are critical for proper planning of a tunnel.  Selection of the alignment, cross section, and construction methods is influenced by the geological and geotechnical conditions, as well as the site constraints. Good knowledge of the expected geological conditions is essential. Tunnel alignment is sometimes changed based on the results of the geotechnical to minimize construction cost or to reduce risks.  The type of the ground encountered along the alignment would affect the selection of the tunnel type and its method of construction.  Study of the impact of geological features on the tunnel alignment in the presence of active or inactive faults. During the planning phase, avoid crossing a fault zone. If it is un avoidable then proper measures for crossing it should be implemented. Presence of faults or potentially liquefiable materials would be of concern during the planning process.  Geotechnical issues such as the soil or rock properties, the ground water regime, the ground cover over the tunnel should be analyzed. The investigation should address not just the soil and rock properties, but also their anticipated behaviors during excavation.
May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  The investigation should also address groundwater. For example, in soft ground SEM tunneling, the stability of the excavated face is greatly dependent on control of the groundwater. Dewatering, pre- draining, grouting, or freezing are often used to stabilize the excavation.  Analyzing the ground behavior during tunneling will affect potential settlements on the surface. Measures to minimize settlements by using suitable tunneling methods or by preconditioning the ground to improve its characteristics would be required.  Risk assessment is an important factor in selecting a tunnel alignment. Construction risks. Sensitive existing structures. Very Hard spots (rock, for example) beneath parts of a tunnel.
May 23, 2020 Tunnels and Tunneling Site Investigation
May 23, 2020 Tunnels and Tunneling Site Investigation
May 23, 2020 Tunnels and Tunneling Site Investigation
May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground Types of Soft Ground  Firm ground : roof can stand for few minutes and sides for much longer time ; eg, dry earth  Soft ground : roof requires immediate support while sides can remain standing for few minutes  Running Ground : required support immediately e.g. dry sand  Self Supporting ground : remain unsupported up to short length of 1.5 to 4m; e.g. sandstone
May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Suitably spaced bent of woods Timber Support for Tunnel excavated in Highly Weathered Phyllite
May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Suitably spaced bent of steel for lagging (covering) Steel Ribs Installation in Super Madi Hydropower Project, Kaski
May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground
May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Liner Plates Installation of Tunnel Liner Plate
May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Fore poling placed to retain material between adjacent bents Fore poling
May 23, 2020 Tunnels and Tunneling Water in Tunnel
May 23, 2020 Tunnels and Tunneling Water in Tunnels After 45 days of construction
May 23, 2020 Tunnels and Tunneling Gases
May 23, 2020 Tunnels and Tunneling Gases
May 23, 2020 Tunnels and Tunneling Gases
May 23, 2020 Tunnels and Tunneling Temperature in Tunnel  Temperature is an important factor in designing and maintaining tunnels, especially in cold regions For example, the frozen damage is destructive to tunnels built in cold regions due to dramatic changes in temperature  The damage includes cracks, water leakage through the lining, and scrap of the main structures  These destructive problems could potentially affect use and maintenance of tunnels. Therefore, understanding tunnel temperature field is critical.  The temperature distribution within tunnel lining and the surrounding rocks is also essential for the analysis of stress and freeze-thaw effect.
May 23, 2020 Tunnels and Tunneling Excavation of Tunnel Cut and cover method A method of tunnel construction involving the installation of earth support systems (e.g. slurry walls) followed by the main excavation, placing of the base slab, roof slab and subsequent backfilling to the final ground level.
May 23, 2020 Tunnels and Tunneling Excavation of Tunnel Sequential Excavation Method : (Drilling and Blasting Method) A method of tunnel construction that involves the use of standard construction equipment for excavation. The tunnel is usually lined in two steps: An initial lining of sprayed concrete provides immediate support and a subsequent secondary or permanent lining is then placed using either sprayed concrete or cast insitu concrete. A waterproof membrane is usually installed between the primary and secondary linings.
May 23, 2020 Tunnels and Tunneling Excavation of Tunnel Tunnel Boring Machine Method : A method of tunnel construction that involves the procurement of a custom made piece of construction equipment. The TBM is equipped with a cutter head that is used to mine the ground. The excavation is continuously supported by installing precast concrete segments within the TBM and grouting them in place as the machine advances.
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Tunnels and tunneling (Engineering Geology)

  • 1. Tunnels and Tunneling Date : May 23, 2020 Time : 1 : 00 P.M. Especially for course of B.Sc. Fourth Year ENGINEERING GEOLOGY Presenter : Sudhan Kumar Subedi Meeting ID : 797 0719 4445 Meeting Password : 8CswQY Interested can Join Zoom Meeting https://us04web.zoom.us/j/79707194445?pwd=VHIxQU0rSGgvbWlvOUd1K2xaN2t6dz09 Basics on
  • 4. May 23, 2020 Tunnels and Tunneling Background  It is understood that first tunnel was constructed by Egyptians and Babylon's about 4000 years ago. This tunnel length – 910 m . width – 360 cm height – 450 cm  Tunnels may be defined as the underground passages or routes excavated through the rocks or soft ground without disturbing the overlaying rocks or soil covers.  In Hindu Religion, in Mahabharat time, during Dwaparyuga, Pandavas get escaped through Tunnel in Lakshagriha for being safe from fire burned by Duryodhan (Kauravs).
  • 5. May 23, 2020 Tunnels and Tunneling Background According to local, About 250 years ago, Our ancestors used to excavate the tunnels for the mining activities for making the coins in this area. Due to the huge over breakage of rock during the excavation, 9 peoples died on site and then it has been closed.
  • 6. May 23, 2020 Tunnels and Tunneling Background  Tunnels are very important structures which are being used in various construction ; like in hydropower project, mining activities, roads, railway for defence purpose and laying of pipelines etc. Classified by Examples of Tunnels Purpose Railway tunnels, metro system, highway tunnels, pedestrian tunnels, water tunnels, sewage tunnels, services tunnels, storage tunnels Geological location/ condition Rock tunnels, earth tunnels, submerged tunnels Cross-sectional shapes Rectangular shape, circular shape, elliptical shape, egg shape, horse-shoe shape and segmental shape  Tunnels can be classified on the different basis as :
  • 7. May 23, 2020 Tunnels and Tunneling Background  Tunnels have different shapes on the basis of their uses and the ground conditions and the availability of materials.
  • 8. May 23, 2020 Tunnels and Tunneling Background Hydropower Tunnel Hydropower Tunnel
  • 9. May 23, 2020 Tunnels and Tunneling Background Road Tunnel Railway Tunnel
  • 10. May 23, 2020 Tunnels and Tunneling Background Silver Mine Tunnel Copper Mine Tunnel
  • 11. May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  Tunneling is a serious engineering project.  In addition to large investment cost, the challenges related to long and deep tunnels are the site characteristics along the alignment routes.  Geology plays a very important role in this. Any adverse and unforeseen geological conditions may influence the safety of tunnels, loss of life, construction time and costs.  When a tunnel or shaft is excavated, the rock stresses are perturbed around the opening and displacements will occur.
  • 12. May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling
  • 13. May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  The physical context and key constraints that influence the planning of a tunnel alignment within the project corridor are : • geology; • water courses; • utilities; • historic structures; and • land use.  The site geology provides the background setting for any underground engineering structure.  The mechanical properties of the rock describe how the geologic materials deform and fail under the forces introduced by the excavation.  The geohydrologic conditions establish the quantity and pressure of water that must be controlled.
  • 14. May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  Geological/ geotechnical investigations are critical for proper planning of a tunnel.  Selection of the alignment, cross section, and construction methods is influenced by the geological and geotechnical conditions, as well as the site constraints. Good knowledge of the expected geological conditions is essential. Tunnel alignment is sometimes changed based on the results of the geotechnical to minimize construction cost or to reduce risks.  The type of the ground encountered along the alignment would affect the selection of the tunnel type and its method of construction.  Study of the impact of geological features on the tunnel alignment in the presence of active or inactive faults. During the planning phase, avoid crossing a fault zone. If it is un avoidable then proper measures for crossing it should be implemented. Presence of faults or potentially liquefiable materials would be of concern during the planning process.  Geotechnical issues such as the soil or rock properties, the ground water regime, the ground cover over the tunnel should be analyzed. The investigation should address not just the soil and rock properties, but also their anticipated behaviors during excavation.
  • 15. May 23, 2020 Tunnels and Tunneling Geological conditions for Tunneling  The investigation should also address groundwater. For example, in soft ground SEM tunneling, the stability of the excavated face is greatly dependent on control of the groundwater. Dewatering, pre- draining, grouting, or freezing are often used to stabilize the excavation.  Analyzing the ground behavior during tunneling will affect potential settlements on the surface. Measures to minimize settlements by using suitable tunneling methods or by preconditioning the ground to improve its characteristics would be required.  Risk assessment is an important factor in selecting a tunnel alignment. Construction risks. Sensitive existing structures. Very Hard spots (rock, for example) beneath parts of a tunnel.
  • 16. May 23, 2020 Tunnels and Tunneling Site Investigation
  • 17. May 23, 2020 Tunnels and Tunneling Site Investigation
  • 18. May 23, 2020 Tunnels and Tunneling Site Investigation
  • 19. May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground Types of Soft Ground  Firm ground : roof can stand for few minutes and sides for much longer time ; eg, dry earth  Soft ground : roof requires immediate support while sides can remain standing for few minutes  Running Ground : required support immediately e.g. dry sand  Self Supporting ground : remain unsupported up to short length of 1.5 to 4m; e.g. sandstone
  • 20. May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Suitably spaced bent of woods Timber Support for Tunnel excavated in Highly Weathered Phyllite
  • 21. May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Suitably spaced bent of steel for lagging (covering) Steel Ribs Installation in Super Madi Hydropower Project, Kaski
  • 22. May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground
  • 23. May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Liner Plates Installation of Tunnel Liner Plate
  • 24. May 23, 2020 Tunnels and Tunneling Tunnel in Soft Ground  Tunnels constructed in soft materials require temporary support immediately or shortly after excavation.  There are various method to provide the support. They are : - Fore poling placed to retain material between adjacent bents Fore poling
  • 25. May 23, 2020 Tunnels and Tunneling Water in Tunnel
  • 26. May 23, 2020 Tunnels and Tunneling Water in Tunnels After 45 days of construction
  • 27. May 23, 2020 Tunnels and Tunneling Gases
  • 28. May 23, 2020 Tunnels and Tunneling Gases
  • 29. May 23, 2020 Tunnels and Tunneling Gases
  • 30. May 23, 2020 Tunnels and Tunneling Temperature in Tunnel  Temperature is an important factor in designing and maintaining tunnels, especially in cold regions For example, the frozen damage is destructive to tunnels built in cold regions due to dramatic changes in temperature  The damage includes cracks, water leakage through the lining, and scrap of the main structures  These destructive problems could potentially affect use and maintenance of tunnels. Therefore, understanding tunnel temperature field is critical.  The temperature distribution within tunnel lining and the surrounding rocks is also essential for the analysis of stress and freeze-thaw effect.
  • 31. May 23, 2020 Tunnels and Tunneling Excavation of Tunnel Cut and cover method A method of tunnel construction involving the installation of earth support systems (e.g. slurry walls) followed by the main excavation, placing of the base slab, roof slab and subsequent backfilling to the final ground level.
  • 32. May 23, 2020 Tunnels and Tunneling Excavation of Tunnel Sequential Excavation Method : (Drilling and Blasting Method) A method of tunnel construction that involves the use of standard construction equipment for excavation. The tunnel is usually lined in two steps: An initial lining of sprayed concrete provides immediate support and a subsequent secondary or permanent lining is then placed using either sprayed concrete or cast insitu concrete. A waterproof membrane is usually installed between the primary and secondary linings.
  • 33. May 23, 2020 Tunnels and Tunneling Excavation of Tunnel Tunnel Boring Machine Method : A method of tunnel construction that involves the procurement of a custom made piece of construction equipment. The TBM is equipped with a cutter head that is used to mine the ground. The excavation is continuously supported by installing precast concrete segments within the TBM and grouting them in place as the machine advances.