BYG DTU. Rock Mass Characterisation in Limestone Ingeniørgeologisk Fjeldklassifikation

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1 BYG DTU Rock Mass Characterisation in Limestone Ingeniørgeologisk Fjeldklassifikation Foredrag i Dansk Geoteknisk Forening Niels Foged Forskningsleder ved DTU-Byg

2 BYG DTU Ingeniørgeologisk Fjeldklassifikation Oversigt Historisk overblik Oversigt over eksamensprojekter, der - i samarbejde med externe projekter og rådgivere - indgår i udviklingen af fjeldklassifikation ved tunnellering i kalk i Øresundsområdet. Fokusering på Eigil Pade s udvikling af Jv-metoden Demonstration af ROCK LAB (Hoek & Brown 2002) Dansk bidrag ved 11th ISRM Congress in Lisboa Portugal 2007: Rock mass characterization for tunnels in Copenhagen Linestone Perspektivering og konklusion

3 BYG DTU Ingeniørgeologisk Fjeldklassifikation Historisk overblik Geoteknisk Institut initierer udviklingen i forbindelse med undersøgelser for Storebælt, Øresundstunnel ved Helsingør og Tunnelbaneundersøgelserne TUBA i København (< ) Stenestad, E. (1976): Københavnsområdets geologi især baseret på citybaneundersøgelserne Fjernvarmetunnel Amager-Østerbro (1975+) Storebælt publiceret i DGF11 No 5 i 1995 Øresund <1991- >1998 -do- Dansk praksis publiceres i DGF1 (1988, 1995) Københavns Metro (1988->2003) DGF-Bulletin 19 fra 2002 med mange bidrag herunder: Kryger Hansen & Foged (2002): kalkens bjergmekaniske egenskaber Citytunneln i Malmø (1997->2005) Projekt EVA 2003: Geological Model and Analysis & Trianglen, Geology and Rock Mechanics Jackson, Steenfelt, Foged & Hartlén ( 2004): Evaluation of Bryozoan limestone properties based on in-situ and laboratory element tests (Ny) Fjernvarmetunnel og Cityringen i København (>2004)

4 BYG DTU Ingeniørgeologisk Fjeldklassifikation Eksamensprojekter ved BYG GEO-sektion Sidsel Ramsdal Stabell (2004): Rock mass classification for construction in the Øresunds region Søren Henningsen (2005): Limestone parameters at elevated temperature and Consequences for the District Heating Tunnel Eigil Pade (2006): Parameter study based on jointed limestone (related to Metro and District Heating Tunnel a.o. Daniela Wilhjelm (2006): Comparison between core logging and face logging results at Malmö Citytunneln (in cooperation with Tech. Univ. Hamburg-Harburg) Ann M. Fugl-Meyer (2007): Optical and Acoustic Televiewer Limestone Classification in the Copenhagen Region by use of Borehole Geophysics

5 Rock Quality Designation BYG DTU

6 BYG DTU RMR Rock Mass Rating Intakte trykstyrke (Point load / Uniaxial Compression) RQD Sprækkehyppighed Sprækketilstand Indstrømning af grundvand Strygning og hældning af sprækker

7 RMR Rock Mass Rating BYG DTU

8 BYG DTU Ingeniørgeologisk Fjeldklassifikation Udvikling af Palmstrøm s Jv metode Eigil Pade (2006) I løbet af den historiske udvikling blev det helt klart at vi ikke kunne bruge RQD vurderet på kerneprøver optaget med top kvalitet udstyr og Barton q-metode baseret herpå. Face-logs under udførelse af tunler og bjergrum i kalk viste RQD > 75% i forhold til RQD på kerner <26%, cif. Stabel (2004) i samarbejde med COWI. Eigil Pade fik derfor som opgave at vurdere og implementere Palmstrøm s volumetric joint count Jv-metode i forbindelse med brug af Hoek & Brown (2002) ROCLAB med brug af data fra Københavns Metro og Fjernvarmetunnel og Malmö Citytunneln (i samarbejde med Daniela Wilhjelm)

9 Malmö Citytunnel Længde: 18 km (6 km tunnel) Dybde under terræn: Ca. 20 m BYG DTU

10 Fjernvarmetunnelen Længde: 4 km Diameter: 4,2 m Dybde under terræn: m BYG DTU

11 Københavns Metro BYG DTU

12 J V Volumetric Joint Count BYG DTU

13 J V Volumetric Joint Count Tre eller flere synlige sprækkesæt Et eller to synlige sprækkesæt BYG DTU

14 J V Volumetric Joint Count BYG DTU

15 Beregning af J V - Sjæleboderne BYG DTU

16 Beregning af J V - Triangeln BYG DTU

17 Beregning af J V - Amagerværket BYG DTU

18 BYG DTU Beregning af J V - Amagerværket J V for øvre københavnerkalk: 4,93 m -1 J V for mellem københavnerkalk: 2,02 m -1

19 BYG DTU

20 Beregning af J V - Amagerværket BYG DTU

21 BYG DTU

22 BYG DTU

23 BYG DTU Hvad skal man stole på? Øvre Københavnerkalk Besøg i skakten: J V = 4,93 m -1 Televiewer log: J V = 1,96 m -1 Core log: J V = 17,58 31,28 m -1 Mellem Københavnerkalk Besøg i skakten: J V = 2,02 m -1 Televiewer log: J V = 0 m -1 Core log: J V = 26,67 over 35 m -1

24 BYG DTU Hoek/Brown Failure Criterion Gør det muligt at beregne styrkeparametre med input fra: GSI Jordrumvægten Intakte trykstyrke β Tunneldybde m i Disturbance factor

25 GSI Geological Strength Index BYG DTU

26 BYG DTU Sammenhæng mellem GSI og J V GSI / Jv correlation Beta = 200 Beta = 36 Beta = GSI Jv

27 Sammenhæng ml. J V og styrkeparametre BYG DTU

28 Styrkeparametre - Sjæleboderne BYG DTU

29 BYG DTU Fjeldklassificering og Bestemmelse af styrkeparametre - konklusion De bedste resultater fås øjensynligt fra in situ målinger Face logs er brugbare, men en grundig sprække registrering er nødvendig Televiewer logs er brugbare, dog skal der passes på lodrette sprækker Core logs er ikke velegnede til sprækkevurdering Med en variation af kendte γ og σ ci værdier, vil gøre det muligt at vurdere en variation af styrkeparametrene.

30 Hoek/Brown Failure Criterion Vis RocLab BYG DTU

31 presentation Rock Mass Characterization for Tunnels in the Copenhagen Limestone Niels Foged, BYG DTU Lisa Jakobsen, Peter Jackson and Lars Erichsen, COWI 11. ISRM Congress July 2007 Lisbon 1 Jun-08 COWI presentation Marine and Geotechnical Engineering

32 Content and Paper position in Proceedings Background The District Heating Tunnel Engineering Geology of limestone in Copenhagen Area Danish limestone classification system Investigations for the District Heating Tunnel and the Mini Metro Comparison of core logging and face logging in limestone Combination of Hoek-Brown GSI- and Palmstrøm Jv-method Optical and Acoustic Televiewer method and some results Conclusion and perspectives The paper may be found in the Proc. 11 ISRM Congress pp COWI presentation

33 Comparison Face Logs and Core Logs A number of tunnel projects in the Copenhagen Area and Malmø in Sweden have called for a better Rock Mass Characterization of Limestone. Initially, much focus was placed on core description which show very low ratings in the different rock mass classification systems. By use of historical data from old tunnels in the Copenhagen area and facelogs during construction of the Mini Metro it was revealed that the core logs were severely influenced by sample disturbance during drilling; Kryger & Foged (2002); Stabell (2004); Pade (2006) etc. COWI presentation

34 Engineering geology of limestone in Copenhagen Area Source: Knudsen et al (1995):The Copenhagen Mini Metro Geological Summary DGU Technical Report. COWI presentation

35 Danish Classification System for Limestone Formations Age Limestone types Degree of induration H1 H2 H3 H4 H5 Description Unlithified Slightly indurated Indurated Strongly indurated Flint Degree of induration Fracturing Designation Degree of fractures Observations No fractures S1 No fractures observed Slightly fractures S2 Distance between fractures is greater than 10 cm. No vertical fractures Fractured S3 Distance between fractures between 6 and 10 cm. Strongly fractured S4 Distance between fractures between 2 and 6 cm. Crushed, fragments S5 Distance between fractures les than 2 cm. COWI presentation

36 District Heating Tunnel District Heating Tunnel shall transmit heat pipelines for water and steam from Amagerværket to Fredensbro in the Østerbro District. 3 shafts with departure and arrival chambers (NATM) 4 km full-face TBM tunnel Ø =5 m. Being compared with Metro Cross-over cavern some 150 to 300 m apart from Adelgade Shaft. COWI presentation

37 Shaft with departure chamber at Amagerværk COWI presentation

38 Comparison Facelogs at Metro Cross-over and Borehole GB02 at Adelgade Shaft COWI presentation

39 Face Log at Cross-over Cavern at Sjæleboderne COWI presentation

40 Comparison of face logs at Metro Cross-Over with boreholes at Adelgade Shaft Degree of induratation Degree of fracturing COWI presentation

41 Application of the Palmstrøm Jv index to provide GSI for use in Hoek & Brown Failure Criterion (Pade, E., MSc.-thesis 2006: Parameter study based on jointed limestone) COWI presentation

42 Danish Limestone Database is used to provide intact compression strength for estimating rock mass properties based on Hoek & Brown Failure Criterion COWI presentation

43 Optical and Acoustic Televiewer (Fugl-Meyer, A., 2007 July) COWI presentation

44 Interpretations 1 Breakouts COWI presentation

45 Interpretation 2: Fractures evaluated from Acoustic and televiewer logs Vertical Fracture Boring induced fractures Open or Closed Fractures? COWI presentation

46 Comparison 3: Induration The acoustic amplitude images can be used to estimate degree of induration by statistical analysis of median (blue) and max (pink) amplitude H1 H2 H2 H5 COWI presentation

47 Categorized and classified degree of induration based on acoustic amplitudes and core classification, respectively Relative Length H1 H2 H3 Categorized H4 H5 H1 H2 H5 H4 H3 Classified H1 < 650 H H H H5 >6000 H1 H2 H3 H4 H5 COWI presentation

48 Conclusions and perspectives Comparison of core samples, televiewer and face logs from the same interval of Copenhagen Limestone show a significant difference in the degree of fracturing A major reason for this is core drilling sample disturbance yielding face logging RQD s approximately 3 to 5 times larger than core logs In-situ observations of the limestone from televiewer logging of borehole walls provides a much better background for rock mass evaluation By combination of Palmstrøm s Jv index to provide GSI for use in Hoek & Brown Failure Criterion and use of Danish Limestone Database rock mass modelling is becoming much more realistic! The coming Copenhagen Ring Metro investigations and design will utilize these findings, hopefully to establish a safe and cost economic construction during the coming years. It includes 17 km tunnels, 17 stations and 5 larger cross-over and bifurcation chambers to be carried out in the coming 11 years. COWI presentation

49 Rock Mass Characterization for Tunnels in the Copenhagen Limestone Thanks for your interest! Thanks to cooperation partners and MSc-students majored from BYG-DTU: COWI RAMBØLL GEO (Danish Geotechnical Institute) Sidsel Stabell (2004) Søren Henningsen(2005) Eigil Pade (2006) Daniella Wilhelm (2006) Ann M.Fugl-Meyer(2007) COWI presentation