1. Settlement of Precast Culverts Under High Fills
The Influence of Construction Sequence and Structural Effects of Longitudinal Strains
Doug Jenkins - Interactive Design Services
Chris Lawson - Reinforced Earth Pty. Ltd.

2. Acknowledgements Joint venture partners for the project:
Roche, Thiess and Linfox.
Project design engineers:
SMEC Australia

3. Introduction Morwell River Diversion
Expansion of Morwell open cut mine
Embankment up to 45 metres high over four coal conveyors
Foundations – approx. 80 metres of brown coal
Anticipated settlements of the order of 1.5 metres

4. Topics The project Construction The design 3D Analysis Results
Provisions for settlement
3D Analysis
Results
Comparison with site measurements
Structural effects

5. Overview Three dimensional effects
Effect of construction sequence / direction
Modelling effects
Materials properties
Structural effects of settlement
Vertical
Longitudinal spreading
Conclusions

6. Morwell River Diversion

16. Foundation Properties

17. Original Analysis

18. Conveyor vertical profiles

20. Construction of Conveyors 210-410

21. Original Analysis – Results; Conveyor 410

22. Original Analysis – Results; Conveyor 310

23. Original Analysis – Results; Conveyor 210

24. Original Analysis – Results; Conveyor 110

25. Measured conveyor settlement over time

26. Simplified 2D Mesh – Conveyor 410

27. Settlement predictions for original and simplified mesh

28. Constructing 3D Model

29. 3D Model

30. 3D Analysis – Results; Conveyor 410

31. 3D Analysis – Results; Conveyor 310

32. 3D Analysis – Results; Conveyor 210

33. 3D Analysis – Results; Conveyor 110

34. Conveyor 210 Settlement with adjusted stiffness parameters

35. Conveyor 410 Horizontal movements from 2D and 3D analyses

36. Conveyor 210 Horizontal movement

37. Conveyor 210 Joint Opening/Closing

38. Summary
Simplified mesh gave good agreement with the original 2D analyses.
3D analysis replicated the main features of the measured settlements - significant influence on the settlements.
Higher settlements at the western end not replicated in the analysis; poorly compacted fill
Some discrepancies found for the southern and northern tunnels (410 and 110); boundary effects
Large horizontal soil movements (tunnel 210).
Joint opening/closing consistent with original analysis.

39. Conclusions
3D effects were shown to have a significant effect on foundation settlements.
Horizontal soil strains need to be considered in the design and detailing of concrete structures under high fills.
3D analysis should be considered for projects where settlements are expected to be large.
Extend 3D models sufficiently far in all directions to avoid edge effects.