Structural Consequences of Tunnel Waterproofing

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1 Structural Consequences of Tunnel Waterproofing Tarcísio B. Celestino Themag Engenharia University of São Paulo - São Carlos 1 Dec 2015

2 1. Inflow estimates and back analyses 2. Types of permanent lining 3. Consequences of potential clogging of geotextiles 4. PVC membrane concrete interaction 5. Spray-on membrane concrete interaction: tests and FEM analysis 6. Creep behavior of PVC membranes subjected to compression 7. Conclusions 2

3 1 Inflow estimates and back analyses 3

4 Inflow back analysis Zuquim Tunnels, São Paulo Metro profundidade

5 Sprayed concrete lining permeability (Celestino, 2001) Zuquim - W Zuquim - E Estacionamento 25 Santa Cecilia Luminarias Shotcrete Bolted cast iron with concrete São Paulo Leste São Paulo Oeste Sé - São Bento Maria Maluf I-A Maria Maluf A-I 20 Bolted cast iron Bolted concrete Toronto subway Greenwich Severn 15 Rotherwhite Blackwall (2) Clyde Blackwall (1) 10 PRR Hudson River Battery Hudson 1,00E-12 1,00E-11 1,00E-10 1,00E-09 1,00E-08 Permeability lining (m/sec) PRR East River Sarnia 5 0 5

6 2 Types of permanent lining 6

7 Options of Sprayed Concrete Lined Tunnels (SCL) (Thomas & Pickett, 2011) Double shell lining (DSL) Sacrificial primary lining for temporary loads Secondary lining for total permanent loads No monolithic behavior Single shell lining (SSL) Primary lining for temporary loads Secondary lining + primary lining for permanent loads Monolithic behavior Composite shell lining (CSL) Primary lining for temporary loads Spray-on waterproofing membrane Secondary lining + primary lining for permanent loads Monolithic behavior 7

8 Double shell and composite shell linings (Thomas & Pickett, 2011) DSL CSL 8

9 Single shell lining No waterproofing membrane Structural role of both primary and secondary layers Infiltrations acceptable (consider evaporation) 9

10 Evaporation in tunnels (AFTES, 1989) Q = 0,01785s(F f)(1 + 0,0862U) Q flow rate (l/h) F water vapor saturation pressure (mm Hg) f ambiente water vapor pressure (mm Hg) s area (m 2 ) U air velocity (m/s) 10

11 ITA WG 12 Shotcrete for Rock Support, 2004 The contributions from different countries illustrate well the widely different views on rock support design. This becomes especially evident when comparing sometimes the overconservative cast in place concrete linings with what evidently is satisfactory support under similar conditions using shotcrete. There are many examples of thickness reduction from one meter down to 10 to 15 cm of shotcrete K. Garshol 11

12 Composite Shell Lining Spray-on membranes Monolithic behavior (ground mass concrete membrane interaction) Different assumptions of sacrifice layer 12

13 Primary Lining (Shotcrete) Secondary Lining (Shotcrete) 13

14 Rotation capacity of plastic hinges (adapted from NBR 6118:2003), where x is the depth of the neutral line and d is the cantilever of reinforcement. 14

15 Single-shell lining Germany (single track tunnels, Pöttler & Klapperich, 2001) Year Ground mass S/M S/M M C Pressure (bar) Thickness (cm) Year Ground mass C M M M C/M Pressure (bar) Thickness (cm) C- claystone; M marl; S - sandstone 15

16 Single-shell lining - São Paulo Metro Single track tunnels (~ 6m diameter) Year: Ground mass: stiff clays and water bearing sands Pressure: 0.5 to 2.0 bar Total thickness (sprayed concrete): 20 to 25 cm 16

17 Comparison of total lining thickness 17

18 São Paulo Metro North Extension (1989) 18

19 Santiago Metro, Estación Cerro Blanco 19

20 Rio de Janeiro Metro - Arcoverde Station 20

21 Stockholm Metro 21

22 3 Consequences of potential cccclogging of geotextiles 22

23 Water pressure on tunnel lining potential clogging of geotextiles (Shin et al., 2005) Time-dependent problem Non-woven geotextiles loose drainage capacity (clogging and compression) Role of permanent lining Limited (or no) long-term instrumentation Coupled numerical analyses 23

24 Loss of geotextile drainage capacity 24

25 Pressure as a function of geotextile drainage capacity 25

26 Secondary lining failure Seoul Metro 26

27 4 PVC membrane concrete interaction 27

28 Experimental Program Ribeiro & Bueno, 2005 Uniaxial compression concrete with PVC membrane and PVC + geotextile 28

29 Concrete and membrane perpendicular flat 29

30 Concrete and membrane perpendicular flat additional displacement sigma x d5-d s (MPa) d (mm) 30

31 Perpendicular undulated membrane CP7 31

32 Perpendicular membrane with voids CP 17 CP s (MPa) d (mm) 32

Relative deformability Membrane 1 a 3 4 a 6 7 a 9 16 a 18 E rel (%) 100 32,5 28,1 24.0 CV (%) 0.01 40.12 42.

33 Relative deformability Membrane 1 a 3 4 a 6 7 a 9 16 a 18 E rel (%) ,5 28, CV (%) Membrane + geotextile 1 a 3 4 a 6 7 a 9 16 a 18 E rel (%) CV (%)

34 Normal stiffness of interfaces Specimens K n (MPa/mm) 4 6 M 38,5 7 9 M 31, M 25,3 4 6 M+G 16,7 7 9 M+G 3, M 3,6 34

35 Direct shear Cisalhamento de interface kpa Tensão (kpa) kpa 75 kpa ,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0 11,0 deslocamento (mm) t = 5 + stan34,3 (kpa) 35

36 5 Spray-on membrane concrete interaction: tests and FEM analysis 36

37 Sprayed concrete linign interaction with sprayed-on membrane (Nakashima et al., 2015; Cambridge and Ruhr Universities) Full scale specimens of sprayed concrete isolated by waterproofing membrane 4-point bending tests to simulate high bending moments Excentric compression tests (high hoop stresses) 37

38 4-point bending test (large bending moments) 38

39 Excentric compression test (high hoop stresses) 39

40 4-point bending test 40

41 Excentric compression test 41

42 4-point bending test typical results 42

43 Analysis of progressive water level rising Density ρ m =2100 kg/m³ ρ s =2400 kg/m³ Cohesion c m =200 kpa Friction angle fm=25º Dilatancy φ m =22,5º Elasticity E m = 3,16 GPa, ν m =0,3 E s = 21 GPa, ν s =0,3 Parameter Normal stiffness Shear stiffness Value 16,0 MPa/mm 3,6 MPa/mm 43

44 Results of strucutural interaction Displacements Normal Stage Relative force WL-4: Stage secondary displacements Internal secondary 4: Plasticity lining forces lining in the lining Bending moment secondary lining Stage 13 2 Stage WL WL--4 Stage of secundary lining 44

45 6 Creep behavior of PVC membranes subjected to compression 45

46 Buoyancy in shaft lined with concrete and sheet membrane N.A 2 N.A 1 U 46

47 Reaction of primary on secondary lining R P R = U - P R = Reaction of primary sprayed concrete U 47

48 Long-term interaction Primary lining membrane secondary lining s e 6MPa s 6MPa s 6MPa t 48

49 Punching test ASTM D 4833 F 8mm tip Non-representative condition 49

50 Creep test under localized load Constant force Time-dependent displacement F F Flat tip Spherical tip 50

51 Test set up 51

52 Typical result s = 6,7 MPa (shade) Sphere diameter= 1.22cm 2,50 Deformação Lenta Deslocamento (mm) 2,00 1,50 1,00 0,50 0, Tempo (s) 52

53 7 - Conclusions 53

54 Inflow criteria: operation conditions and durability Adavantages of umbrella-type systems: lower structural demand; pre-grouting eventually needed Use of sheet membranes does not allow primary secondary lining interaction Spray-on membranes allow primary secondary lining interaction Long term compression of sheet membranes on sprayed concrete surfaces not recommended Importance of the role of final lining 54

55 Thank you!!!

Passage under Lövstavägen at Bypass Stockholm From Design to Realization

Passage under Lövstavägen at Bypass Stockholm From Design to Realization Roslin Mattias 1, Borio Luca 2 and Tomas Hellström 3 1 Swedish Transport Administration, Solna Strandväg 98, 171 54 Solna, mattias.roslin@trafikverket.se