Outline of the Execution Manual for Outline of the Execution Manual for Seismic Retrofitting of Existing Pile Seismic Retrofitting of Existing Pile
Foundations Foundations with High Capacity Micropileswith High Capacity Micropiles
Masashi ITANIMasashi ITANITakeshi OSHITATakeshi OSHITA
Seiichi ONODERASeiichi ONODERA
IWM200IWM20033
Public Works Research InstitutePublic Works Research InstituteConstruction Technology Research Team.Construction Technology Research Team.
Contents of the Executive ManualContents of the Executive Manual3.6.1 Grout Mixture
3.6.2 Weighing and mixing of grout
3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes
4.2.1 Reinforcing materials
4.2.2 Grout
3.4.1 Boring method 4.2.3 Pile head steel pipes
3.4.2 Boring machine and boring tools 4.2.4 Quality control items
3.4.3 Boring
3.4.4 Confirmation of bearing ground
3.4.5 Treatment following boring
4.4 Schedule control
4.5 Safety control
4.6 Conserving enveronment
4.7 Execution records
3.5 Installing reinforcing materials
3.6 Grout injection
3.7 Reinserting HMP steel pipes
3.8 Treatment of the pile head
3.9 Expansion of footing
CHAPTER 4 EXECUTION MANAGEMENT
4.1 Execution management items
4.2 Quality control of materials
4.3 Confirming the bearing capacity of HMP
3.1 Execution process
3.2 Major machinery and equipment
3.3 Preparatory work
3.4 Boring
2.1 Basic items
2.2 Preliminary surveys
2.3 Execution planning
CHAPTER 3 EXECUTION METHOD
CHAPTER 1 GENERAL
1.1 Scope
1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION
3.6.1 Grout Mixture
3.6.2 Weighing and mixing of grout
3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes
4.2.1 Reinforcing materials
4.2.2 Grout
3.4.1 Boring method 4.2.3 Pile head steel pipes
3.4.2 Boring machine and boring tools 4.2.4 Quality control items
3.4.3 Boring
3.4.4 Confirmation of bearing ground
3.4.5 Treatment following boring
4.4 Schedule control
4.5 Safety control
4.6 Conserving enveronment
4.7 Execution records
3.5 Installing reinforcing materials
3.6 Grout injection
3.7 Reinserting HMP steel pipes
3.8 Treatment of the pile head
3.9 Expansion of footing
CHAPTER 4 EXECUTION MANAGEMENT
4.1 Execution management items
4.2 Quality control of materials
4.3 Confirming the bearing capacity of HMP
3.1 Execution process
3.2 Major machinery and equipment
3.3 Preparatory work
3.4 Boring
2.1 Basic items
2.2 Preliminary surveys
2.3 Execution planning
CHAPTER 3 EXECUTION METHOD
CHAPTER 1 GENERAL
1.1 Scope
1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION
Caputure 1 Caputure 1 :: GemeralGemeral
This manual covers thThis manual covers the e execution of seismic execution of seismic retrofittingretrofitting of of existing pexisting pile foundationsile foundations using using hihigh capacity micropilesgh capacity micropiles. .
ScopeScope
Contents of the Executive ManualContents of the Executive Manual3.6.1 Grout Mixture
3.6.2 Weighing and mixing of grout
3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes
4.2.1 Reinforcing materials
4.2.2 Grout
3.4.1 Boring method 4.2.3 Pile head steel pipes
3.4.2 Boring machine and boring tools 4.2.4 Quality control items
3.4.3 Boring
3.4.4 Confirmation of bearing ground
3.4.5 Treatment following boring
4.4 Schedule control
4.5 Safety control
4.6 Conserving enveronment
4.7 Execution records
3.5 Installing reinforcing materials
3.6 Grout injection
3.7 Reinserting HMP steel pipes
3.8 Treatment of the pile head
3.9 Expansion of footing
CHAPTER 4 EXECUTION MANAGEMENT
4.1 Execution management items
4.2 Quality control of materials
4.3 Confirming the bearing capacity of HMP
3.1 Execution process
3.2 Major machinery and equipment
3.3 Preparatory work
3.4 Boring
2.1 Basic items
2.2 Preliminary surveys
2.3 Execution planning
CHAPTER 3 EXECUTION METHOD
CHAPTER 1 GENERAL
1.1 Scope
1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION
3.6.1 Grout Mixture
3.6.2 Weighing and mixing of grout
3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes
4.2.1 Reinforcing materials
4.2.2 Grout
3.4.1 Boring method 4.2.3 Pile head steel pipes
3.4.2 Boring machine and boring tools 4.2.4 Quality control items
3.4.3 Boring
3.4.4 Confirmation of bearing ground
3.4.5 Treatment following boring
4.4 Schedule control
4.5 Safety control
4.6 Conserving enveronment
4.7 Execution records
3.5 Installing reinforcing materials
3.6 Grout injection
3.7 Reinserting HMP steel pipes
3.8 Treatment of the pile head
3.9 Expansion of footing
CHAPTER 4 EXECUTION MANAGEMENT
4.1 Execution management items
4.2 Quality control of materials
4.3 Confirming the bearing capacity of HMP
3.1 Execution process
3.2 Major machinery and equipment
3.3 Preparatory work
3.4 Boring
2.1 Basic items
2.2 Preliminary surveys
2.3 Execution planning
CHAPTER 3 EXECUTION METHOD
CHAPTER 1 GENERAL
1.1 Scope
1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION
Caputure 2 Caputure 2 :: GENERAL ITEMS GENERAL ITEMS CONCERNING EXECUTIONCONCERNING EXECUTION
Major Items Surveyed in Preparation for ExecutionMajor Items Surveyed in Preparation for Execution
CategoryCategory Survey itemSurvey item
Working environment conditionsWorking environment conditions
Limit on overhead spaceLimit on overhead space
Plane execution yard conditionsPlane execution yard conditions
State of surrounding roadsState of surrounding roads
Existing structuresExisting structures
Adjacent structures and underground structuresAdjacent structures and underground structures
State of rivers etc.State of rivers etc.
Execution groundExecution ground
Temporary equipmentTemporary equipment
Natural conditionsNatural conditions
Surrounding environment Surrounding environment conditionsconditions
State of surrounding regionState of surrounding region
State of nearby roadsState of nearby roads
Legal restrictions on construction workLegal restrictions on construction work
Byproducts of constructionByproducts of construction
Ground conditionsGround conditionsSoilSoil
GroundwaterGroundwater
Preliminary surveysPreliminary surveys
Limit on overhead spaceLimit on overhead space
In order to retrofit an existing pile foundation, In order to retrofit an existing pile foundation, the restriction onthe restriction on the overhead spacethe overhead space imposed imposed byby overhead wiresoverhead wires,, the superstructurethe superstructure,, the beam the beam of the bridge pierof the bridge pier etc.etc.
4m4m
Preliminary surveysPreliminary surveysSurvey of the execution yard conditionSurvey of the execution yard condition
The plane layout of the execution yard must The plane layout of the execution yard must be studied bybe studied by surveying the site boundaries surveying the site boundaries, , structuresstructures and and uses under girdersuses under girders, , areasareas and and locationslocations that can be used as the working yard, that can be used as the working yard, level differences of the ground etc.level differences of the ground etc.
Preliminary surveysPreliminary surveys Survey of adjacent and underground structureSurvey of adjacent and underground structure
Structural specifications of existing structures Structural specifications of existing structures ((existing footings, bridge piers etcexisting footings, bridge piers etc.), structures .), structures adjacent to the site where HMP is adjacent to the site where HMP is installedinstalled, and , and the locationthe location and and state of underground structuresstate of underground structures must be thoroughly surveyed.must be thoroughly surveyed.
Contents of the Executive ManualContents of the Executive Manual3.6.1 Grout Mixture
3.6.2 Weighing and mixing of grout
3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes
4.2.1 Reinforcing materials
4.2.2 Grout
3.4.1 Boring method 4.2.3 Pile head steel pipes
3.4.2 Boring machine and boring tools 4.2.4 Quality control items
3.4.3 Boring
3.4.4 Confirmation of bearing ground
3.4.5 Treatment following boring
4.4 Schedule control
4.5 Safety control
4.6 Conserving enveronment
4.7 Execution records
3.5 Installing reinforcing materials
3.6 Grout injection
3.7 Reinserting HMP steel pipes
3.8 Treatment of the pile head
3.9 Expansion of footing
CHAPTER 4 EXECUTION MANAGEMENT
4.1 Execution management items
4.2 Quality control of materials
4.3 Confirming the bearing capacity of HMP
3.1 Execution process
3.2 Major machinery and equipment
3.3 Preparatory work
3.4 Boring
2.1 Basic items
2.2 Preliminary surveys
2.3 Execution planning
CHAPTER 3 EXECUTION METHOD
CHAPTER 1 GENERAL
1.1 Scope
1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION
Major machinery and equipmentMajor machinery and equipment
Sample of Standard Execution Machinety anSample of Standard Execution Machinety and Equipmentd Equipment
Workcategory
Name Specifications Quantity Remarks
Boringmachine
Motor about110PS
1 unitRotary percussion double-wall pipemethod
Water feedpump
15kW 1 unit Ejection rate 300l/min
Water tank 5, 10m3Necessary
numberFor pure water, for slurry
Sand pump 5.5kWNecessary
numberPipe extractor 1 unit Used as necessaryGrout mixer 11kW 1 unit Vertical or two tank horizontal typeGrout pump 15kW 1 unit Ejection rate 300l/minWater meter 1 unitFlow meter 1 unit Used as necessaryCompressor 1 unit
Liftingcapacity4.9 to 25t
Engine drivengenerator
Approx. 45,100kVA
1 unit Used as necessary
1 unit
Boring
Injection
CommonCrane
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
The installing angle is set using a The installing angle is set using a slant rule.slant rule.
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
Boring using 1.5m short HMP steel Boring using 1.5m short HMP steel pipes (as standard) as a casing.pipes (as standard) as a casing.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Boring MethodBoring MethodSelection of Boring Method Accoding to GroSelection of Boring Method Accoding to Gro
und Categoryund Category
Sandy orcohesive
soilGravel
Soilcontaining
stonesSoft rock
Mediumhard rock
Hard rock
Rotary percussion double-wallpipe method ◎ ◎ ◎ ○ ○ ○
Down-the-hole hammerdouble-wall pipe method ○ ○ ○ ◎ ◎ ◎
Boring method
Ground categorySoil Rock
Ring bit Drill pipe
Coupling Drill pipe
Water swivel Drive adapter Shank rod (hammer-sub)
エキステンションロッド
エキステンションロッドインナーロッド
インナービット
リングビット
インナービット
リングビット
カップリング
カップリング
エキステンションロッド
インナーロッド
HMP鋼管
カップリング
カップリング
HMP鋼管
クリーニングアダプター
ウォータースイーベル
クリーニングアダプター
スイーベル
イシュー
シャンクロッド
シャンクロッドHMP鋼管 HMP鋼管
Inner bit Inner rod
Extension rod
Ring bit HMP steel pipe Coupling HMP steel pipe
Inner bit Inner rod Coupling Extension rod
Ring bit HMP steel pipe Coupling HMP steel pipe Cleaning adapter
Swivel
Issue Shank rod
Coupling
Extension rod
Extension rod
Cleaning
adapter
Water
swivel
Shank rod
down-the-hole hammerdown-the-hole hammer Rotary percussionRotary percussion
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
The inside of the borehole is washed The inside of the borehole is washed with pure water or air.with pure water or air.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Water or AirWater or Air
BoringBoring
Boring shall be performed byBoring shall be performed by an all-casing an all-casing methodmethod to protect a borehole wall. At this time to protect a borehole wall. At this time HMP steel pipes shall be used asHMP steel pipes shall be used as the casingthe casing. If . If the boring is completed, the inside of the the boring is completed, the inside of the borehole shall beborehole shall be carefully washed to remove carefully washed to remove slimeslime..
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
The injection hose and core bars are The injection hose and core bars are inserted into the borehole together. inserted into the borehole together.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
The injection hose and core bars are inserThe injection hose and core bars are inserted into the borehole togethor.ted into the borehole togethor.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Grout injectionGrout injection
The grout mixtureThe grout mixture must must be set so that it satisfies be set so that it satisfies the design strength of the design strength of 30N/mm30N/mm22 or more or more, and the , and the stipulated workability stipulated workability during pumping and during pumping and injection.injection.
Grout MixtureGrout Mixture
Water Cement Ratio Air content
W/C (%)(%) Water Note 1) Cement
W C50 1 605 1210 Approximately 1.5C%
Unit weight (kg/m3)
Chemical admixtures Note 2)
Sample Grout MixtureSample Grout Mixture
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
groutgrout
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
Pressure injection is perfomed to the stipuPressure injection is perfomed to the stipulated depth each time HMP steel pipes are wlated depth each time HMP steel pipes are without.ithout.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
HMP steel pipes are reinserted to the stipulated depth.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process
Treatment of pile head.
Installing a boring machine Mixing grout
Casing boring Initial injection
Washing borehole interior Pulling out HMP steel pipesPressure injection
Withdrawing inner rod
Reinserting HMP steel pipesInserting injection hose
Installing core bars Treatment of pile head
Bor
ing
Inje
ctio
n
Treatment of the pile headTreatment of the pile headPile head steel pipes Pile head steel pipes
and a footing are and a footing are connected by connected by a a bearing plate bearing plate methodmethod or or shear ring shear ring methodmethod..
HMP steel pipesHMP steel pipesCore barsCore bars
Bearing plateBearing plate
Reinforcing barsReinforcing bars
HMP steel pipesHMP steel pipes
Shear ringShear ringCotter
NutNut
Shrinkage compensating groutShrinkage compensating grout
HMP steel pipesHMP steel pipesCore barsCore bars
Bearing plateBearing plate
Reinforcing barsReinforcing bars
HMP steel pipesHMP steel pipes
Shear ringShear ringCotter
NutNut
Shrinkage compensating groutShrinkage compensating grout
Contents of the Executive ManualContents of the Executive Manual3.6.1 Grout Mixture
3.6.2 Weighing and mixing of grout
3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes
4.2.1 Reinforcing materials
4.2.2 Grout
3.4.1 Boring method 4.2.3 Pile head steel pipes
3.4.2 Boring machine and boring tools 4.2.4 Quality control items
3.4.3 Boring
3.4.4 Confirmation of bearing ground
3.4.5 Treatment following boring
4.4 Schedule control
4.5 Safety control
4.6 Conserving enveronment
4.7 Execution records
3.5 Installing reinforcing materials
3.6 Grout injection
3.7 Reinserting HMP steel pipes
3.8 Treatment of the pile head
3.9 Expansion of footing
CHAPTER 4 EXECUTION MANAGEMENT
4.1 Execution management items
4.2 Quality control of materials
4.3 Confirming the bearing capacity of HMP
3.1 Execution process
3.2 Major machinery and equipment
3.3 Preparatory work
3.4 Boring
2.1 Basic items
2.2 Preliminary surveys
2.3 Execution planning
CHAPTER 3 EXECUTION METHOD
CHAPTER 1 GENERAL
1.1 Scope
1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION
CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENTPROCESS : BoringPROCESS : Boring
Management item Managed content Management method Standard valueMeasurement
frequencyEccentricity D/4D: Diameter of
steel pipeBoring angle Boring angle Slant rule ±1° All
Slime sampling,absence of artesian
confirmation of bearinglayer 1 time/1 pile
Design boringor more
Cleanliness of returnwater
Quantity of residualslime
Visually All
Presence/absence of
State of boring Visually
Boring lengthMeasuring rod,measuring tape
All
Obstructions All
Boring location Scale All
Bearing layerdepth, design
value
All
Boring location
Boring depth
Eccentricity : D/4Eccentricity : D/4
DD
CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENTPROCESS : BoringPROCESS : Boring
Management item Managed content Management method Standard valueMeasurement
frequencyEccentricity D/4D: Diameter of
steel pipeBoring angle Boring angle Slant rule ±1° All
Slime sampling,absence of artesian
confirmation of bearinglayer 1 time/1 pile
Design boringor more
Cleanliness of returnwater
Quantity of residualslime
Visually All
Presence/absence of
State of boring Visually
Boring lengthMeasuring rod,measuring tape
All
Obstructions All
Boring location Scale All
Bearing layerdepth, design
value
All
Boring location
Boring depth
±± 11 °°
CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENT
PROCESS : Grout injectionPROCESS : Grout injectionManagement item Managed content Management method Standard value
Measurementfrequency
State of Quantity of injection Flow meter Allgrout injection Pressure Pressure gauge All
Specific gravity ofoverflowing grout
Specific gravity gauge(mud balance), scales
Mixed specificgravity ±2%
1 time/1 pile
Chloride ion content ofoverflowing grout
Dry chemistry method Max. 0.30kg/m3 1) 1 time/1 pile
Design strengthor more
Bleeding ratio ofoverflowing grout
Polyethylene bag usedfor measuring bleeding
3% (after 3 hours) 1 time/1 pile
1 time/1 pileCompressive strength of
overflowing groutCompressive testing
This is established This is established in conformity with in conformity with the the Japan Concrete Japan Concrete Standard SpecificationsStandard Specifications..
CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENT
PROCESS : Installation of reinfoecing materPROCESS : Installation of reinfoecing materialial
±50mm±50mm
Management item Managed content Management method Standard valueMeasurement
frequency
State of insertionLocation of pile head
(standard height)Level measurement ±50mm All
State of insertionLocation of pile head
(standard height)Level measurement ±50mm All
CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENT
PROCESS : Pile head treatmentPROCESS : Pile head treatmentManagement item Managed content Management method Standard value
Measurementfrequency
Eccentricity D/4D: Diameter of
steel pipe
Pouring anglePouring angle of pile
headSlant rule ±2.5° All
Scale AllPile location Pile location
Eccentricity : D/4Eccentricity : D/4
±2.5°±2.5°
DD
Confirming the bearing capacity of HMPConfirming the bearing capacity of HMP
In principle, one of the In principle, one of the following shall be following shall be performed to confirm the performed to confirm the bearing capacity of HMPbearing capacity of HMP
(1) A test pile is executed to confirm (1) A test pile is executed to confirm the execution properties and to the execution properties and to perform a vertical loading test. perform a vertical loading test.
(2) The design bearing capacity is (2) The design bearing capacity is confirmed to perform a vertical confirmed to perform a vertical loading test on an actual pile. loading test on an actual pile.
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000
1570(kN)
981(kN)
1177(kN)
687(kN)
It is performed by creating It is performed by creating a low level straina low level strain by by lightly striking the pile head with a hand held lightly striking the pile head with a hand held hammer and hammer and measuring the response at that measuring the response at that timetime with an accelerometer. with an accelerometer.
Hand hammerHand hammer
Acceleration senserAcceleration senser
computercomputer
pile
pile
Outline of the Integrity testOutline of the Integrity test
Speed
depth
time
time
Pile
length
(L
)
time
time
speed
depth
Pile length (L)
Principle of the Integrity testPrinciple of the Integrity test
3@1,500=4,500
3,000750750 2,250750
pipelod
Grout
500 7501,500
6,750
25017
8
Case1Case1
Tese caseTese case
1 m3
m
45°
Case2Case2
Tese caseTese case
Case1Case1
-0.008
-0.006
-0.004
-0.002
0
0.002
0.004
0.006
-1 0 1 2 3 4 5 6 7 8
杭長(m)
(m/s
)速
度
杭頭杭頭
鋼管先端鋼管先端
杭先端杭先端
The reflection The reflection from the end of from the end of the steel pipe the steel pipe and the end of and the end of the pile is the pile is clearly clearly observedobserved..
length
spee
d
Pile head
end of the steel pile
End of the grout
resultresult
CaseCase 22
土中試験
-0.008
-0.006
-0.004
-0.002
0
0.002
0.004
0.006
-1 0 1 2 3 4 5 6 7 8(m/s
)速
度
増幅処理未処理
杭頭杭頭
鋼管先端鋼管先端
杭先端杭先端
土中試験
-0.008
-0.006
-0.004
-0.002
0
0.002
0.004
0.006
-1 0 1 2 3 4 5 6 7 8(m/s
)速
度
増幅処理未処理
杭頭杭頭
鋼管先端鋼管先端
杭先端杭先端
resultresult
Length(m)
spee
d
Pile head
end of the steel pile
End of the grout
杭頭
グラウト拡大部
杭先端
m
杭頭
グラウト拡大部
杭先端
m
This created a longer anchored portion than originally designed.This created a longer anchored portion than originally designed.
Ground testGround test
1,500
1,500
1,500
4,500
7,500
1,500
支持層
1,500
1,500
1,500
4,500
7,500
1,500
支持層
1,500
1,500
1,500
4,500 7,500
1,500
CONCLUSIONCONCLUSION The effect on the ground can be reduced by proThe effect on the ground can be reduced by pro
cessing the amplitude of the measured waveform, cessing the amplitude of the measured waveform, even for HMPs with their complex structure.even for HMPs with their complex structure.
The reflecting wave form the grout expansion pThe reflecting wave form the grout expansion portion, the end of the steel pipe, and the pile can ortion, the end of the steel pipe, and the pile can definitely be measured to a certent.definitely be measured to a certent.
Applicability for HMP quality controlApplicability for HMP quality control
・・ We believe an effective method would be to compare We believe an effective method would be to compare tthe survey results for all the HMPshe survey results for all the HMPs and to select those pil and to select those piles that can be expected to perform poorly based on a reles that can be expected to perform poorly based on a relative evaluation.ative evaluation.
Thank you for your attention.Thank you for your attention.
ENDEND