development of pressure penetrating pipe(ppp) pile for enhancement of bearing capacity 2013.04.17...
TRANSCRIPT
Development of Pressure Penetrating Pipe(PPP) Pile for Enhancement of Bearing Capacity
2013.04.17
Do, Eunsu
Seoul National University Geotechnical & Geoenvironmental Engineering Lab
1. Introduction 1. Introduction
Contents
2. Durability Performance Test 2. Durability Performance Test
3. Load Test Plans 3. Load Test Plans
4. Summary & Further Study 4. Summary & Further Study
Introduction
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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 x 2m)
Small and light penetrating equipment
(4 small hydraulic jack + guide steel bar + pressure plate)
Grouting
Introduction
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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
Vibration, Noise,
Dust
Durability Performance Test
Certification of Test
5/14
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
Test equipments Model Manufacturer
5MN Compression tester
CCH-5000KNI SIMADZU/JAPAN
Static data logger YCAM-500A KYOWA/JAPAN
Durability Performance Test
Test object installation
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Hydraulic Pump
500Ton Load Cell
Test Ob-
ject
Data Logger
Durability Performance Test
Test Results
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0
100
200
300
500
400
600
Load(kN
)
Repeat
Count
0
100
200
300
500
400
600
Load(kN
)
Repeat
Count
500kN
6,667Times
Test object Hydraulic Jack(50Ton)
Repeat count
6,667(cycles)>>1,000
Results- No oil leaking
- load of over 500kN induced
Durability Performance Test
After test completion
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Load Test Plans
Purpose of Load Test
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Load-settlement relationships
Bearing capacity of pile
Load transfer analysis
Test # of pile Times
Load test 1 8 times
Plans of Load Test
Weathered rock placed in
relatively shallow
depths(5~8m)
Test pile installation depth:
10~15m
Load Test Plans
Plans of Load Test
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Load Test Plans
Considering Factors – Strain gage
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Strain gageStrain gage
Concrete Concrete Concrete
Soil Soil SoilWelding
Plate(Aluminu
m)
Welding Weld-
ingSpacerConnecting
lines
Connecting
lines
Connecting
lines
Plan 1 Plan 2 Plan 3
Φ216.3-12t, L=1m
Pipe
pile Φ216.3-12t, L=1m
Pipe
pile Φ216.3-12t, L=1m
Pipe
pile
Load Test Plans
Considering Factors – Strain gage
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Plan 1 Plan 2 Plan 3
Detailed Plan
Price of strain gauge 400,000 won 25,000 won 200,000 won
Processing cost of pile 25,000 won 40,000 won 20,000 won
Damage from welding Little Little Heat transfer by bolt
Advantages &Disadvantages
- Minimize damage- High cost- Limited depth(30cm)
- Many similar cases- Able to cut and process surface
- Low reliability of data- Minimize effect of stiffness- High cost- Limited depth(30cm)
Load Test Plans
Considering Factors – Load Cell
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Hydraulic
Jack
Hydraulic Jack Hydraulic
Jack(50.0t
f)
(50.0t
f)
(50.0t
f)
Concrete Concrete Concrete
Soil Soil Soil
Pressure
Plate
Pressure
Plate
Pressure
PlateInstall
Plate
Install
Plate
Pipe Pile
Plan 1 Plan 2 Plan 3
Pipe Pile Pipe Pile
Φ216.3-12t Φ216.3-12tΦ216.3-12t
Summary & Further study
The PPP pile method has many advantages compared to the existing con-
struction method. However, there are disadvantages and not many construc-
tion 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 comple-
tion.
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.
Summary
Further study
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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