Grouting using PUR in extreme geological and weather conditions in Iceland By Tomasz Najder, Ph.D Civ. Eng. Senior Consultant, Najder engineering, SE-133 36 Saltsjöbaden Sweden 1 ready

Location of the projects Breiđalsheiđi and Botnsheiđi Project 1993-1994 Héðinsfjarðargöng Project 2007-2009 Kárahnjúkar Hydropower Project 2006-2008 Location of the projects 2 ready

3 Icelandic geology 3 2 cm/year 2 cm/year Nord-America Plate Eurasia Plate Eurasia Plate Icelandic geology 3 press ready 3

Case study – Ísafjörður Project (road tunnels): grouting for rock sealing and stability. Conditions: very high water ingress from the fault under high water pressure into D&B tunnels. Water pressure ~ approx. 60 bars Water inflow ~ 50 l/s/hole Water temperature ~ +20 ºC ready

Limited rock permeability for cement based grouts Ísafjörður Location of Ísafjörður press ready

fault 2 Leakage 1.000 l/s !!! No probe holes !!! fault 1 press ready

X = wash-out Rock grouting in Breiđalsheiđi and Botnsheiđi (Iceland) 1993-1994 Water pressure ~ approx. 60 bars Water inflow ~ 50 l/s/hole Water temperature ~ +20 ºC fault water Water velocity ~ 3m/s = wash-out X ready Cement grouting ????

mineral component (OMC) (sequential grouting) 1-component PUR Hydrophilic PUR – limited range of penetration! components A+B Component B - polyisocyonate 2-component PUR Component A - polyol components A+B components A+B Proposal: 2-component PUR or mineral component (OMC) (sequential grouting) press press press ready

Final result of grouting Drilling and grouting pattern for Fault 2 Drilling and grouting pattern for futher “normal” chainage Fault 2 Inserting of mechanical packers in high water pressure conditions Final result of grouting Drilling for grouting press ready

Case study - Kárahnjúkar Headrace Tunnels: grouting for rock sealing and stability. Conditions: very high water ingress under water pressure of 20 bars into D&B and TBM tunnels. Cold water (+1 °C - +65 °C ). Very wide faults filled with clay and boulders ready

Kárahnjúkar Hydropower Project 2006-2008 Diversion Tunnels at dam 2.4 km (Kar 14) Headrace Tunnel 53.0 km (Kar 14) Grouting galleries at dam  0.5 km    (Kar 14) Cable tunnel  1.0 km Hraun Diversion 2.0 km Grjótá Diversion 1.75 km Adit 1 1.4 km (Kar 14) Adit 2 2.7 km (Kar 14) Adit 3 2.8 km (Kar 14) Surge Tunnel 1.7 km (Kar 14) Drainage Tunnel 0.7 km (Kar 14) Penstocks 0.82 km (2x) Access to Powerhouse 1.0 km Tailrace Tunnel 1.3 km Total Tunnel Length: 73.0 km (D&B=10 km, TBM=63 km) Kárahnjúkar Hydropower Project 2006-2008 11 press press ready 11

TBM D&B press ready

Low temperature problems with cement based grouts Climate Low temperature problems with cement based grouts ready

14 14 Gravel and clay filled fault at the cutterhead Stage 2: huge water ingress from the fault; TBM cutterhead passed the fault Stage 3: wash-out of the fill from the fault (TBM) Stage 4: material washed out from the fault Stage 1: TBM in progress in water scenery 14 ready 14

Wide fault (coobles “cemented” with clay) Question of time.... Water:+1 °C ÷ +65 °C press ready

16 Bimbar inflatable reusable packers after one inserting operation Double set of BVS inflatable, disposable, none drillable packers How to insert the packer ???? press ready 16

One-component PU resins Fast reacting two-component PU resins Fast setting two-component urea-silicate resins (foams) ready

Fault above tunnel invert (D&B) after wash-out of fill material ca. 8m Fault above tunnel invert (D&B) after wash-out of fill material ready

Solution chosen → urea – silicate foam SPECIFIC CARACTERISTIC IN PRACTICAL APPLICATION   WILKIT FOAM T GEOFOAM PUMPING SYSTEM SIMILAR INJECTION RATIO 1/1 EXPANSION RATIO (V) FILLING DRY HOLES AT 10º C AT 25º C   V 20 V 40 V 15 V 30 RATIO OF PERFORMANCE IN VERY HIGH WATER FLOW AS SEEN IN KARAHNJUKAR 40 - 50% > 80 - 90% COUNSELLED TO INJECT AGAINST HIGH WATERFLOWS + +++ TOUGHNESS OF FOAM FIRE PROTECTION EURO CLASS B2 ready

Case study - Héðinsfjarðargöng Project (road tunnels): grouting for rock sealing and stability. Conditions: very high water ingress under water pressure of 40 bars into D&B tunnels. Cold water (+2 °C). Very wide faults filled with clay and boulders. Sections with unstable tunnel’s faces and crowns ready

Water inflow into Icelandic rock mass: - Ólafsfjördur Tunnel ready

Ólafsfjörður Tunnel. Water in front of the face: water ingress in the hole ~ 50 l/s Ólafsfjörður Tunnel. Water in front of the face: water ingress ~ 5-30 l/s/hole ready

Water ingress in heavy leaking zones ready

Héðinsfjarðargöng Project - leakage at the face of Ólafsfjördur Tunnel Héðinsfjarðargöng Project – face collapse at Ólafsfjördur Tunnel   ready

Fault above tunnel invert before wash-out of fill material Fault above tunnel invert after wash-out of fill material ready

Fault above tunnel invert after PUR pre grouting ready

Large fault grouted with PUR (Ólafsfjörður Tunnel) Stone from the face grouted with PUR - solid form like amber of PU resin (Ólafsfjörður Tunnel) Large fault grouted with PUR (Ólafsfjörður Tunnel) Stone from the face grouted with PUR - solid form like amber of PU resin (Ólafsfjörður Tunnel) ready PUR as “hard” amber (Ólafsfjörður Tunnel)

λ WilkitFoam, GeoFoam λ = 15÷30 x CarboPur λ = 3÷5 x Factor λ 28 wash-out effect ground water velocity 15 mm/sec De Neef Scandinavia AB 1991 Factor λ = relation between volume of material grouted / material still remaining in the rock mass after hardening vs. ground water velocity in mm/s press press ready 28

Water is enemy to cement based grouts (dilution) water cement particles ready 29

PU resins love water for reaction polyurethanes water ready 30

PUR and OMR OPC or PUR ??? Hydraulic conductivity < Lu ≈ 10-15 Winter conditions (temp. + 3-5 ºC) High water velocity Big caverns press ready

Thank You for Your attention! THE END Thank You for Your attention! ready