1. Xiao-ying Zhuang Tongji University 2006. Oct. 21 A study on Permeable Design of Parallel Seepage Tunnel Group

2. Tongji University Tunnelling & Underground Space Hydropower Station Construction Status quo in China Increase in Total Augmentation Capacity

3. Tongji University Tunnelling & Underground Space Jingping Hydro Power Station under Construction

4. Tongji University Tunnelling & Underground Space Jingping Hydro Power Station under Construction

5. Tongji University Tunnelling & Underground Space Jingping Hydro Power Station under Construction

6. Tongji University Tunnelling & Underground Space Traditional Design Criteria Impervious design idea Load-structure method

7. Tongji University Tunnelling & Underground Space Impervious design idea Impervious design idea Crack width verification ω max ≤0.3mm Traditional Design Criteria

8. Tongji University Tunnelling & Underground Space Background Information T TT The Pubugou hydropower station, about 200 km away from the urban area of Cheng-du in Sichuan Province, has a total augmentation capacity over 3000kW and a reservoir capacity over 5,390 million cubic meters.

9. Tongji University Tunnelling & Underground Space Background Information T TT The initial design stage gave a dual-layer 18Ф32 reinforcement rations for tunnel lining of lower part in rock Grade IV, which is unreasonable for substantial construction due to the load-structure method and crack limit requirement of 0.25mm it employs.

10. Tongji University Tunnelling & Underground Space Problems to be solved by impervious model  H How to prove steel ratios is over estimated by impervious design?  I Impractical dense reinforcement ratio !  A An reasonable reinforcement ratio based on permeable design should be given.  W We are not sure if hydraulic splitting could be avoided by Norway Method which is gained from empirical acknowledgement.

11. Tongji University Tunnelling & Underground Space Calculation Model Upper Part Inclined Part Lower Part

12. Tongji University Tunnelling & Underground Space Porous Media Material Property  Rock, as permeable material, its permeability is mainly controlled by joints and structure surfaces.  Concrete has a constant permeability coefficient under steady seepage field.

13. Tongji University Tunnelling & Underground Space Lining Element Beam element or truss element is usually adopted for the concrete lining in FEM analysis of tunnel. As the lining is assumed porous media material, 4 edge 8 node solid element is selected.

14. Tongji University Tunnelling & Underground Space Unfavorable Load combinations Tectonic stress is unfavorable when the tunnel is empty for maintenances. The tunnel inner force is mostly under compressive stress. If tectonic stress field is counted for operation stage the results might be more on the unsafe side

15. Tongji University Tunnelling & Underground Space Stress Field – Inner Force M (kN · m) N (kN) Q (kN) Construction Stage ( impervious )

16. Tongji University Tunnelling & Underground Space Operation Stage (impervious) Stress Field – Inner Force

17. Tongji University Tunnelling & Underground Space Operation Stage (impervious) Stress Field – Inner Force M (kN · m) N (kN) Q (kN)

18. Tongji University Tunnelling & Underground Space Stress Field – Inner Force Operation Stage (Permeable)

19. Tongji University Tunnelling & Underground Space Stress Field – Inner Force Operation Stage (Permeable) M (kN · m) N (kN) Q (kN)

20. Tongji University Tunnelling & Underground Space Comparisons of Analysis Results (Permeable) (Impervious)

21. Tongji University Tunnelling & Underground Space Comparisons of Analysis Results (Permeable) (Impervious)

22. Tongji University Tunnelling & Underground Space Comparisons of Analysis Results (Permeable) (Impervious)

23. Tongji University Tunnelling & Underground Space Seepage Field – Operation Stage

24. Tongji University Tunnelling & Underground Space Seepage Field – Maintenances Stage

25. Tongji University Tunnelling & Underground Space Seepage Field – Maintenances Stage

26. Tongji University Tunnelling & Underground Space Thanks for your attention!