Part 30 MAPEI. OPC, MC or PUR III-2012

Transcription

1 Part 30 MAPEI OPC, MC or PUR III-2012 (Part 30 MAPEI, PP 2007, animation+p/r : final short version) Copyright notice Unauthorised copying of this presentation as whole or in parts in any form or by any means, electronic, photocopying, recording or otherwise, without prior written permision is prohibited. 1

2 Holter, Hognestad, Garshol 2001 The seepage of water in hardrock occurs along channels within the discontinuities of the rock mass. Between the discontinuities the rock material is often practically impermeable. The conductivity of the rock mass depends on the properties of the discontinuities. 2

3 Dalmalm 2004 Grouted zone around the tunnel with penetration length l and hydraulic conductivity* K g Correct grouting K g < K None correct grouting K g K (!) 3

4 OPC MC, UFC 4

5 The real crack is not academic pipe like in doctor s thesis 5

6 The groutability of fine cracks is related to the width of the crack and the grain size of the grout material, exed as a groutability ratio for rock in the following formula (Weaver 1991): 15% Hansen 2003 For groutability ratios greater than 5, grouting is considered consistently possible. For groutability ratios less than 2, grouting is not considered possible. 6

7 d D/d D/d = min 6 (at too high pumping rate) D OPC water-cement ratio Penetration of cement grouts; D/d vs. water-cement ratio (Axelsson, Gustafson 2007) 7

8 The ability of a grout to penetrate cavities, channels and porous material (penetrability) depends on two things: rheology and filtration tendency. Extensive laboratory tests on stable, low w/c-ratio grouts show that the most significant limitation to their penetrability is the tendency of cement grains to agglomerate into an impermeable filter cake besides of flocculation due to o-filtraction 8

9 Flocculation means a gathering together or clotting of fine particles in a dispersed state to form lager agglomerations. When Portland cements and bentonite (especial in high dosage) are mixed together with water, the solid particles flocculate due to electrostatic attraction between the positive and negative charge sites on the particles. Bleed develops as the cement particles settle due to the effects of gravity and allow free water to bleed from the suspension. If a grout has Presso-filtration is a measure of bleed under high bleed capacity, it will not fully fill ure. The ure filtration coefficient is the pore space within the soil or a measure of how much water is forced out of fractures in a rock due to the bleed a sample under ure in a given period of water which forms as it sets. time. For stable grouts, bleed should be as Injecting grouts into small apertures is similar low as possible (preferably less than to ing the grout against a filter material. 2%), but in no case should be more The filtration tendency of the grout is the than 5%. property of the grout whereby a plug of grain can be formed at the crack opening or within the crack. 9

10 Ordinary Portland Cement - partially penetration 10

11 ... for what?? Apparent viscosity measurements by means of Marsh Funnel (Marsh Viscosity) to the left and bleeding with the 1 liter traditional graduated cylinder to the right Abreu J.V

12 0.10 mm PLUG!!! Penetrability Grout passed meter Amount through test of for passed different OPC grouts through filters (MC, different in penetrability UFC) instead used filters meter of bleed test test! 12

13 Higher Blaine value [cm 2 /g] larger reactive surface higher flocculation tendency 13

14 Particle sizes of microcements Fine cement Surface Area = High (if you add fine fillers) D 95 = 50 microns Very fine cement, but with much over sized particles Microcement Surface Area = High D 95 = 10 microns 14

15 The graph below summarizes the more peculiar characteristics of the MC grout mix from the injection point of view. According to those results: - With ratios between 0.90 and 0.95 we have the best compromise between stability and viscosity. - For lower ratios the mixes must be thinned with superplasticiser admixtures, while for higher ratios is required a stabilization with bentonite. The combination of bentonite and superplasticiser is lowering both the yield stress and viscosity of grout to values under certain time comparable with chemical grouts. = bentonite superplasticiser Blaine 6000 [cm 2 /g] 15

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18 OPC, MC, UFC - lower tendency for o-filtration = better penetration 18

19 Bleeding?? Test for o-filtration!!! Superplasticiser??? Deflocculant!!! 19

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21 ure (bar) shear stress Typical rheological laws for two types of fluids Water ure tests (Lugeon tests) Cohesion OPC Cohesion water (= 0) Viscosity OPC Viscosity water OPC Binghamian fluid α viscosity yield stress (cohesion) Bindham yield point Water = Newtonian fluid grout flow (l/min) shear strain or shear rate Cement suspension water!!!!! Lugeon test is performed with Newtonian fluid Grouting is performed with Binghamiam fluid 21

22 Amenability Amenability is the ability of the particular grout to penetrate joints and other defects premeated with water. It is defined by the amenability coefficient (A c ) of the grout, which is exsed as follows: A c = Lu gr Lu wa = fracturing!!! where: A c = amenability coefficient Lu gr = Lugeon permeability of the grout Lu wa = Lugeon permeability of water The grout rheology is to be adjusted so as to maintain as high an amenability coefficient as possible. This should generally be greater than 75%, and preferably higher. (Nauts 1995) 22

23 Convenient in low temperatures 23

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25 fault 2 Leakage l/s!!! No probe holes!!! fault 1 25

26 Rock grouting in Breiđalsheiđi and Botnsheiđi (Iceland) Water ure ~ approx. 60 bars Water inflow ~ 50 l/s/hole Water temperature ~ +20 ºC fault water Water velocity ~ 3m/s = wash-out X Cement grouting???? 26

27 1-component PUR Hydrophilic PUR limited range of penetration! components A+B Component B - polyisocyonate Component A - polyol 2-component PUR components A+B components A+B Proposal: 2-component PUR or mineral component (OMC) (sequential grouting) 27

28 Blockage of the leakage. Comive semirigid foam Hard resin cement PU (A+B): 1. Blocker grout 2. Fine fissures grouting Free CO 2 escapes further and helps 2 nd penetration Sequential grouting with cement and 2-component polyurethanes 28

29 Climate Low temperature problems with cement based grouts 29

30 Gravel and clay filled fault at the cutterhead Stage Stage 3: 4: wash-out 2: 1: material huge TBM in water of progress washed the ingress fill out from in water from from the the the fault scenery fault; fault (TBM) TBM cutterhead passed the fault 30

31 Wide fault (coobles cemented with clay) Question of time... Water:+1 C +65 C 31

32 Injekteringscement 30 d 15 soil_2 / d 85 grout = 10 d 60 soil_2 / d 10 soul_2 = 2,08 d 15 soil_2 / d 85 grout = 6 d 60 soil_2 / d 10 soul_2 = 2,40 d 85 grout = 0,04 mm d 15 soil_1 = 0,40 mm d 15 soil_2 = 0,24 mm Groutability of soils 32

33 PUR permeation in sand and gravel (low ure grouting) Permeation grouting Coarse grained crushed material, well cemented with hard clay after PUR grouting 33

34 Permeation grouting in moraine (water glas) Fracturing by grouting in sand (water glas) Fracturing by grouting in till (PUR) 34

35 ca. 8m x Fault above tunnel invert (D&B) after wash-out of fill material. Re-filling with OMR 35

36 Water inflow into Icelandic rock mass: - Ólafsfjördur Tunnel 36

37 Ólafsfjörður Tunnel. Water in in front of of the the face: water ingress in ~ the 5-30 hole l/s/hole ~ 50 l/s 37

38 Héðinsfjarðargöng Project - leakage face collapse at the face at Ólafsfjördur of Tunnel Tunnel 38

39 Fault above tunnel invert before after wash-out of fill material 39

40 Fault above tunnel invert after PUR pre grouting 40

41 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) PUR as hard amber (Ólafsfjörður Tunnel) 41

42 Water is enemy to cement based grouts (dilution) water cement particles 42

43 PU resins love water for reaction polyurethanes water 43

44 λ WilkitFoam, GeoFoam λ = x CarboPur λ = 3 5 x wash-out effect 15 mm/sec ground water velocity [mm/min] 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/min 44

45 Hydraulic conductivity < Lu PUR and OMR OPC or PUR??? Winter conditions (temp ºC) High water velocity Big caverns 45

46 OPC?? MC?? PUR?? The right answer????? 46

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48 THE END Thank You for Your attention! 48

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