1. PILE TESTING Mike Turner (Applied Geotechnical Engineering)

2. August 2004 2Pile Testing Types of load testing Static load testing Static load testing Maintained Load (ML) Maintained Load (ML) Constant Rate of Penetration (CRP) Constant Rate of Penetration (CRP) Dynamic load testing Dynamic load testing

3. August 2004 3Pile Testing Static load tests on micropiles Features: High slenderness ratio (=Aspect Ratio) High slenderness ratio (=Aspect Ratio) Relatively high elastic shortening Relatively high elastic shorteningImplies: Long piles = large pile head settlement Long piles = large pile head settlement

4. Pile Testing4 August 2004 Pile length vs Pile head settlement at working load: Micropiles in soils

5. Pile Testing5 August 2004 Pile length vs settlement at working load Micropiles in soils (2) 0.25mm/m 0.5mm/m 0.1mm/m

6. Pile Testing6 August 2004 Pile length vs Gross pile head settlement at working load – Micropiles into rock

7. Pile Testing7 August 2004 Pile length vs settlement at working load Micropiles into rock (2) 0.35mm/m 0.4mm/m 0.2mm/m

8. Summary (1) For a wide variety of soils: Gross pile settlement at working load is Proportional to pile length Proportional to pile length Around 0.25mm/metre, on average Around 0.25mm/metre, on average (As high as 0.5mm/metre) (As high as 0.5mm/metre) (As low as 0.1mm/metre) (As low as 0.1mm/metre) Independent of diameter (and load) Independent of diameter (and load)

9. Summary (2) For a wide variety of rocks: Gross pile settlement at working load is Proportional to pile length Proportional to pile length Around 0.35 mm/metre, on average Around 0.35 mm/metre, on average (As high as 0.4 mm/metre) (As high as 0.4 mm/metre) (As low as 0.2 mm/metre) (As low as 0.2 mm/metre) Independent of diameter (and load) Independent of diameter (and load)

10. Spooky!

11. Pile Testing11 August 2004 Pile head settlement vs working load: Micropiles in soils

12. Pile Testing12 August 2004 Pile head settlement vs working load: Micropiles in soils (2) 0.012mm/kN 0.035mm/kN 0.005mm/kN

13. Pile Testing13 August 2004 Pile head settlement vs working load: Micropiles into rock

14. Pile Testing14 August 2004 Pile head settlement vs working load: Micropiles into rock (2) 0.01mm/kN0.004mm/kN 0.02mm/kN (variable)

15. Summary (1) For a wide variety of soils: Gross pile head settlement at working load is: Around 0.012 mm/kN (0.1mm/tonne [metric]) Around 0.012 mm/kN (0.1mm/tonne [metric]) [As high as 0.035mm/kN (0.35 mm/tonne)] [As high as 0.035mm/kN (0.35 mm/tonne)] [As low as 0.005 mm/kN (0.05 mm/tonne)] [As low as 0.005 mm/kN (0.05 mm/tonne)] (Fairly) independent of length and actual load! (Fairly) independent of length and actual load!

16. Summary (2) For a wide variety of rocks: Gross pile head settlement at working load is: Around 0.01 mm/kN (0.1mm/tonne [metric]) Around 0.01 mm/kN (0.1mm/tonne [metric]) (for most practical purposes) (for most practical purposes) May be as high as 0.02 mm/kN (0.2 mm/tonne) May be as high as 0.02 mm/kN (0.2 mm/tonne) May be as low as 0.004mm/kN (0.04 mm/tonne) May be as low as 0.004mm/kN (0.04 mm/tonne) Still fairly independent of length and load! Still fairly independent of length and load!

17. August 2004 17Pile Testing Even spookier!

18. Conclusion/discussion Apparent similarities of relationships? Bearing stratum generally stronger than Bearing stratum generally stronger than overburden overburden Piles designed on shaft friction alone Piles designed on shaft friction alone Grout-to-ground design conservative Grout-to-ground design conservative Structural design essentially identical Structural design essentially identical