The document discusses the design of precast segmental tunnel linings used for shield tunneling. It covers key aspects of segmental lining design including geometry, calculation of internal forces, reinforcement design, segment manufacture, waterproofing, and types of tunnel boring machines (TBMs) used for shield tunnel excavation.

1. Precast Segmental Lining Design W.K. Kong (2007)

10. Segmental Lining Design – Lining Geometry Key block design Principle issues: a) Limiting obliqueness of angle (as surface becomes twisted) b) Ensuring can be inserted by TBM segment erector

11. Segmental Lining Design – Lining Geometry Key block design Principle issues: a) Limiting obliqueness of angle (as surface becomes twisted) b) Ensuring can be inserted by TBM segment erector

12. Segmental Lining Design – Lining Geometry

20. Segmental Lining Design – Calculation of Internal Forces Effects of Poor Ring Build

21. Segmental Lining Design – Calculation of Internal Forces Effects of Poor Ring Build

22. Segmental Lining Design – Calculation of Internal Forces Effects of Poor Ring Build

23. Segmental Lining Design – Calculation of Internal Forces Grouting loads (annulus and secondary grouting): Assessment: a) Determine  grout for Annulus Primary and Secondary Grouting; b) Check using Muir-Wood (1976) – Stage 1 will give Big Thrust, Zero Moment, Stage 2 will give Small Thrust, Large Moment

25. Segmental Lining Design – Calculation of Internal Forces TBM propulsion jacking loads: Assessed using Guyon (1972)

26. Segmental Lining Design – Calculation of Internal Forces Seismic Design – Use method of Wang (1991) Assess impact of: a) Axial deformation along tunnel b) Curvature deformation along tunnel c) Ovaling of tunnel profile Normally, no special joints are required, more reinforcement may be needed.

29. Segmental Lining Design – Calculation of Internal Forces Reinforcement Design:

30. Segmental Lining Design – Calculation of Internal Forces Reinforcement Design Design of reinforcing quantity and layout needs to accommodate: a) Design loading; b) Distribution to limit crack widths and cover for durability; c) Limit damage (accidental or under loading) around bolt pockets, lifting socket, segment corners, etc).

31. Segmental Lining Design – Calculation of Internal Forces Reinforcement Design:

33. Bolt Design Design principles: Bolts are intended to: a) Aid ring build quality b) Compress gaskets c) Provide safety prior to annulus grout hardening Bolts can be curved or straight (steel or plastics). Bolts and washer assemblies do not need waterproofing

34. Segment Manufacture Documentation required: a) Segment design drawings; b) Segment mould shop drawings; c) Specification on casting, concrete mix, steel fixing, etc. d) Tolerances for mould, steel fixing, etc.

35. Waterproofing Design Main waterproofing elements: a) Gaskets on all joints with hydrophilic inserts in gaskets b) Use of hydrophilic strips c) Provision of caulking groove Soil side Drive direction

36. Waterproofing Design Gasket design: Need to check against poor ring build and bolt capacity

37. TBM Introduction Type of TBM ( (According AFTES Association) Ground support Main TBM Types None Beam TBM Road Header With Shied Support only Open Shield Machine With Shield and Front support Earth pressure balance Machine Slurry Machine Compressed air shield

38. TBM with no shield and frontal support Main Beam and Reamer Beam Machine Road Header

39. TBM with open shield Double Shield TBM Single Shield TBM

40. Closed Shield TBM – Slurry Machine Confinement is achieved by pressurizing boring fluid inside the cutterhead chamber

43. Closed Shield TBM – EPBM Shield Tail skin Mucking and support functions trailing Ring building and annulus grouting Propulsion / steerage Excavation Active pre-cast concrete tunnel lining support

45. TBM OPERATION – Erecting for launch Launching shaft prepared Lower part of shield, bulkhead and drive rams Installing main drive

46. TBM OPERATION – Erecting for launch Upper shield and drive rams Lower part of tail-skin Ring erector installed Cutter-head installed

47. TBM OPERATION – Erecting Al Bugeisha for launch Completed shield and tail-skin Prepared launching eye with seals

48. TBM OPERATION – Segmental tunnel lining Stack of 3 test rings Ring placed in TBM tail skin Ground is not exposed Segment casting Soil Annulus grout Key block

49. PORE WATER PRESSURE IN SCREW Soil conditioning improves hydraulic gradient in screw TBM OPERATION – Application of EPB face pressure h o h 1 Ratio of h 1 /h o is linearly proportional to achievable effective face pressure h 2 Second screw is a risk mitigation measure Soil conditioning = higher effective face pressure

53. TBM Selection – Face stability Yoshikowa et al (1980) Requires measures to maintain slurry pressure Slurry TBM requires heavy de-siltation facilities Slurry requires secondary separation treatment High risk of blockages particularly when N>15 APPLICABILITY OF SLURRY TBM FOR COMPARISON

54. TBM Selection Geological Profiles