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

3/14

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

4/14

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

6/14

Hydraulic Pump

500Ton Load Cell

Test Ob-

ject

Data Logger

Durability Performance Test

Test Results

7/14

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

8/14

Load Test Plans

Purpose of Load Test

9/14

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

10/14

Load Test Plans

Considering Factors – Strain gage

11/14

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

12/14

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

13/14

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

14/14

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