Development of Pressure Penetrating Pipe(PPP) Pile for Enhancement of Bearing Capacity

1. Development of Pressure Penetrating Pipe(PPP) Pile for Enhancement of Bearing Capacity 2013.04.17 Do, Eunsu Seoul National University Geotechnical & Geoenvironmental Engineering Lab

2. Contents 1. Introduction 2. Durability Performance Test 3. Load Test Plans 4. Summary & Further Study

3. Introduction Concepts of PPP Pile • Method using hydraulic jacking device to penetrate pipe piles by pressure • Able to check bearing capacity by pressure of hydraulic jacking device • High workability in narrow areas (0.6m x 0.6m x2m) • Small and light penetrating equipment (4 small hydraulic jack + guide steel bar + pressure plate)

4. Introduction Advantages No vibration or noise No need to clear near pile after construction Compact jacking devices Construction possible for limited areas Checking of correct pile bearing capacity possible Disadvantages Not many construction cases Difficulty in penetration when amber or boulders exist Research Plans Estimation of pile bearing capacity through load tests – Load transfer analysis, base & shaft resistances Assessment of penetration availability according to soil conditions – Check the applied load through load cell Grouting Vibration, Noise, Dust

5. Durability Performance Test Certification of Test Test object: Hydraulic jacking device(50Ton) Test method 1) Method: operate jacking device so a load of over 500kN is induced 2) Target lifetime:6,667 cycles 3) Velocity: within 30 seconds per cycle 4) Load drop under 500kN or oil leaking should not happen after target lifetime Environment of Laboratory: 25±5℃, 50±25% Test equipments

6. Durability Performance Test Test object installation 500Ton Load Cell Test Object Data Logger Hydraulic Pump

7. Durability Performance Test Test Results 600 500 400 Load(kN) 300 200 100 0 Repeat Count 600 500kN 500 400 Load(kN) 300 200 100 0 Repeat Count 6,667Times

8. Durability Performance Test After test completion

9. Load Test Plans Plans of Load Test Purpose of Load Test Load-settlement relationships Bearing capacity of pile Load transfer analysis Weathered rock placed in relatively shallow depths(5~8m) Test pile installation depth: 10~15m

10. Load Test Plans Plans of Load Test

11. Load Test Plans Considering Factors – Strain gage Plan 2 Plan 3 Plan 1 Concrete Concrete Concrete Welding Welding Welding Soil Soil Soil Connecting lines Connecting lines Connecting lines Spacer Plate(Aluminum) Strain gage Strain gage Pipe pile Pipe pile Pipe pile Φ216.3-12t, L=1m Φ216.3-12t, L=1m Φ216.3-12t, L=1m

12. Load Test Plans Considering Factors – Strain gage

13. Load Test Plans Considering Factors – Load Cell Plan 2 Plan 3 Plan 1 Hydraulic Jack Hydraulic Jack Hydraulic Jack (50.0tf) (50.0tf) (50.0tf) Pressure Plate Pressure Plate Pressure Plate Install Plate Install Plate Concrete Concrete Concrete Soil Soil Soil Pipe Pile Pipe Pile Pipe Pile Φ216.3-12t Φ216.3-12t Φ216.3-12t

14. Summary & Further study Summary The PPP pile method has many advantages compared to the existing construction method. However, there are disadvantages and not many construction cases. According to a result of the durability performance test, When a load of 500kN in the hydraulic jack was induced, there are no oil leaking after test completion. Load test plans were made considering the economic feasibility of strain gage and the installation of load cell. Analysis on load transfer and bearing capacity of piles will be conducted after completion of load test. Further study Estimation of pile bearing capacity through load tests – Load transfer analysis, base & shaft resistances Assessment of penetration availability according to soil conditions – Check the applied load through load cell 14/14