In the Name of God

1. In the Name of God

2. The University of Isfahan Faculty of Science Dept. of Geology Stability analysis for an underground excavation support system, the Khadangestan water conveyance tunnel, Iran By : M. Hashemi , Asst. Prof. & H. Boor , M.Sc. student

3. CONTENTS • Project Area • Geology of the Area • Experimental Studies • Rock Mass Characteristics • Rock Mass Classification • Stability Analysis & Support Prediction • Conclusions

4. PROJECT AREA Location of the Project & Access Roads

5. PROJECT AREA (GEOLOGY & FEATURES) • Project Features : • 13 Km Length ; 7 segments ; Horseshoe section ; Transferring 60 million m3 water • Geology of the Area • predominant rocks : limestone, marly limestone, marl argillaceous limestone and shale • high structural deformation and very high in situ stresses in the past ; series of locally weak and broken zones

6. Geological map of the study area and the Khadangestan tunnel enroute

7. Outcrop of the shaly Limestone intercalated with the calcareous shale

8. A view of the marly limestone unit in the eastern side of Khadangestan valley

9. An example for the complexity of foliation in massive limestone, Khadangestan valley

10. water flowing from Khadangestan spring in mid October

11. EXPERIMENTAL STUDIES • Field Explorations: • Borehole drilling & extensive core logging including the joints’ characterization • Laboratory Tests: • Physical properties (index) tests • Mechanical (engineering) properties tests: UCS ; triaxial

12. EXPERIMENTAL STUDIES

13. ROCK MASS CHARACTERIZATION • Discontinuities • RQD = 115-3.3 Jv where, Jv is the volumetric joint count and was calculated as: • Jv = 1/Siwhere Si is the spacing of it joint set. Si values are available from field data for joints. • For RMR89>23 GSI = RMR89-5 • For RMR89<23 GSI = 9LogeQ+44 where Q is the modified classification system of Barton et al. as follows: • Q = (RQD/Jn)*(Jr/Ja) (5)

14. ROCK MASS CHARACTERIZATION • Q system parameters: For GSI>25(Undisturbed rock mass): • mb/mi = exp{(GSI-100)/28} (6) • S = exp{(GSI-100)/9} ; a = 0.5 For GSI<25(Undisturbed rock mass): • s = 0 ; a = 0.65-GSI/200 where mb & mi are constants for rock mass. s and a are constants that depend upon rock mass properties. In above equation mi is constant of intact rock, which obtained using Hoek-Brown criterion for the intact rock: • σ1 = σ3+ σc(mi σ3/ σc+1)1/2 (11) • σ1 = σ3+ σc(mb σ3/ σc+s)a (13)

15. Discontinuities Characterization along the 6th segment tunnel enroute

16. Statistical analysis of discontinuioties’ characteristics along the 6th segment tunnel enroute

17. ROCK MASS CHARACTERIZATION Geological & geotechnical langitudinal section for the 6th segment tunnel enroute

18. SUPPORT PREDICTION FROM VARIOUS EMPIRICAL METHODS (6TH SEGMENT)

19. SUPPORT PREDICTION FROM VARIOUS EMPIRICAL METHODS (6TH SEGMENT)

20. ROCK MASS PARAMETERS H-B Criterion M-C Criterion Strength parameters for the H-B & M-C criteria

21. ROCK MASS INSTABILITY A view of the landslide, the 6th segment tunnel inlet

22. Rock-support interaction analysis result for the 6th segment tunnel enroute (1st part)

23. Rock-support interaction analysis result for the 6th segment tunnel enroute (2nd part)

24. DEM Analysis (using UDEC) Maximum & minimum principal stress directions in rock mass around the 6th segment tunnel

25. DEM ANALYSIS (using UDEC) Horizontal stress(Pa) in rock mass around the 6th segment tunnel

26. DEM ANALYSIS (using UDEC) Vertical stress (Pa) in rock mass around the 6th segment tunnel

27. DEM ANALYSIS (using UDEC) Horizontal displacement (m) in rock mass around the 6th segment tunnel

28. DEM ANALYSIS (using UDEC) Vertical displacement (m) in rock mass around the 6th segment tunnel

29. CONCLUSIONS • Due to almost uniform lithology, the most predominant rocks along the tunnel enroute are shaly & marly limestones. • The area is located in the Sanandaj-Sirjan strutural zone and therefore, there is high structural complexity in the area. • There is only karstification potential in the 1st segment • The rock mass around the tunnel mostly lies in the weak-fair as per RMR & Q classifications , whereas it lies in the medium-strong category as per RMi. • Rock mass may suffer from heavy squeezing in the 3rd segment. The maximum overburden is expected in the 1st segment (potential spalling). • The RMR method gives heavier support than Q & RMi methods (due to 10-m limitation in RMR tables). • As per the DEM analysis, maximum displacements in crown, sidewall & invert are 12 , 30 & 6 mm, respectively, showing potential block falls in crown & sidewall • The shotcrete, shotcrete-steel combination and shotcrete-rock bolt combination have maximum and minimum Pi and Ui.Therefore, it is better to use shotcrete as short-term support and rock bolts or steel rib for high overburden and very weak zones.

30. Thanks for your attention

31. DEM ANALYSIS (using UDEC)

33. نتايج حاصل از تحليل پايداري براي مسير تونل قطعه اول خدنگستان

34. مقطع ژئوتکنيکي قطعه دوم مسير خط انتقال آب خدنگستان

35. مقطع ژئوتکنيکي تونل قطعه سوم مسير خط انتقال آب خدنگستان

36. نتايج حاصل از تحليل پايداري براي تونل قطعه سوم خدنگستان

37. مقطع ژئوتکنيکي تونل قطعه چهارم مسير خط انتقال آب خدنگستان

38. نتايج حاصل از تحليل پايداري براي تونل قطعه چهارم

39. مقطع ژئوتکنيکي تونل قطعه پنجم مسير خط انتقال آب خدنگستان

40. شرايط كلي پايداري براي مسير تونل قطعه پنجم

41. مقطع ژئوتکنيکي تونل قطعه هفتم مسير خط انتقال آب خدنگستان

42. نتايج حاصل از تحليل پايداري براي تونل قطعه هفتم

45. توزيع آماري خصوصيات دسته درزه ها در مسير تونل قطعه اول

46. قطعه اول

47. قطعه اول

49. قطعه سوم

50. قطعه سوم