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Measurement for land slide slope stability using High

Capacity Micropiles

Masao SAGARAMasao SAGARA(Fujita Corporation)(Fujita Corporation)

Prof. Masaru HOSHIYAProf. Masaru HOSHIYA(Musashi Institute of Technology)(Musashi Institute of Technology)

Good evening! (Good, afternoon!)My name is MASAO SAGARA.We applied HMP on the slope in exit of the tunnel.We executed the field measurement.I will present result of it.

I introduce the result of field measurement.

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We applied HMP on the slope in the exit of the tunnel.We executed the field measurement.

HMP in the Retaining Wall

Good evening! (Good, afternoon!)My name is MASAO SAGARA.We applied HMP on the slope in exit of the tunnel.We executed the field measurement.I will present result of it.

I introduce the result of field measurement.

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ContentsContents

1.Background & Outline of the 1.Background & Outline of the ConstructionConstruction

2.Purpose of Field measurement 2.Purpose of Field measurement 3.Field measurement result of 3.Field measurement result of

High Capacity MicropilesHigh Capacity Micropiles4.Conclusion4.Conclusion

I would like to speak four contents.1.Background & Outline of the Construction2.Purpose of Field measurement 3.Field measurement result of High Capacity Micropiles4.Conclusion

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Background(Site location)Background(Site location)

TOKYO

This is the site location from Google Earth.It is a site of the tunnel construction. The name is called BESHO tunnel.

This is the site location from Google Earth.It is a site of the tunnel construction. The name is called BESHO tunnel.

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BESHO Tunnel L=948m

NEW Expressway

L=100km

ISE Bay

TOUMEI

Expressway

TOKAI Belt LineCHUOH Expressway

MEISHIN

Expressway

SURUGA Bay

NAGOYA City

Background(Site location)Background(Site location)

TOKYO

In Japan, there are two expressways where Tokyo is connected with Nagoya.Tokyo is located besides the right of the screen.One is a CHUOH expressway, and another is a TOUMEI expressway. These two expressways are connecting by the new expressway. It is constructing, now.One of tunnels on this expressways is BESHO tunnel.The length is 948m. Here, HMP was constructed.

In Japan, there are two expressways where Tokyo is connected with Nagoya.Tokyo is located besides the right of the screen.One is a CHUOH expressway, and another is a TOUMEI expressway. These two expressways are connecting by the new expressway. It is constructing, now.One of tunnels on this expressways is BESHO tunnel.The length is 948m. Here, HMP was constructed.

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Exit

The Forestry RoadPrivate House

Serpentinite Crystalline schist

Epidote -Amphibolite

Shallow overburden(18m)Subsurface layers

Outline of the ConstructionOutline of the ConstructionExit of tunnel terminal sideExit of tunnel terminal side

((longitudinallongitudinal vertical section)vertical section)

Crystalline schist

Tunnel

There is a private house and the forestry road up soon about the tunnel.If the tunnel is dug without the reinforcement construction method, the house will be leaning to one side.And, the slope will be failure, too.

This figure is a longitudinal vertical section of the tunnel. There is a private house and the forestry road up soon about the tunnel.If the tunnel is dug without the reinforcement construction method, the house will be leaning to one side.And, the slope will be failure, too.

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All Ground Fasten Method (AGF）

For TunnellingFor Slope StabilityThe three countermeasures were

applied for the slope stability.

•Extension of entrance of tunnel(8m)

•Rock Bolt

•High Capacity Micropilewith Ground Anchor

Countermeasure Against Landslide Countermeasure Against Landslide and Tunneling and Tunneling

However, the exit of the tunnel has been extended. As a result, the amount of cut has been reduced.

In the first plan, the exit of the tunnel was here.And, it was scheduled to be cut.

All Ground Fasten Method was applied to the tunneling.

Like this, a small slope failure and a large-scale slope failure were forecast.

The lock bolt was constructed to a small slope failure.

HMP with the ground anchor were constructed to a large-scale slope failure.

This figure shows countermeasure against landslide and tunneling.All Ground Fasten Method was applied to the tunneling.And, three countermeasures were applied for the slope stability.In the first plan, the exit of the tunnel was here.And, it was scheduled to be cut.However, the exit of the tunnel has been extended. As a result, the cut amount has been reduced.Like this, a small slope failure and a large-scale slope failure were forecast.The lock bolt was constructed to a small slope failure.HMP with the ground anchor were constructed to a large-scale slope failure.

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CConstructiononstruction position position in ground plan

Private House

林道

Construction position of High Capacity Micropiles

The Forestry Road

Tunneling

•HMP was constructed near the tunnel. •11 piles•L=13.0-17.5m@1.5m•Total Length 149m

This figure shows the construction position of HMP.

HMP was constructed near the tunnel. 11 piles were constructed.The length is from 13 to 17m.The total length is 149m.

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Construction positionConstruction position

Panorama of Site

HMP Construction Position

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Drilling situationDrilling situation

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Drilling completionDrilling completion

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Connection of Pile headConnection of Pile head

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HMP seen from mountain sideHMP seen from mountain side

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The process for Retaining WallHigh capacity Micro-Piles

Φ178@11piecesL=13.0～17.5m＠1.5m

CradleRetaining Wall strip(H150 beam)

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The process for Retaining WallThe process for Retaining Wall(Placing of reinforcement)(Placing of reinforcement)

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The process for Retaining WallThe process for Retaining Wall(Concrete placement)

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Purpose of field measurement Purpose of field measurement

We aim to confirm the effect of HMP control works on the slope.

The strain gauges ware put on HMP, and the bending moment was measured on the site.

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Measurement PilesMeasurement PilesThe vinyl chloride pipe with The vinyl chloride pipe with the strain gauges was set the strain gauges was set up in the steel pipe.up in the steel pipe.The strain gauges of The strain gauges of installation sections ware installation sections ware six places.six places.

The vinyl chloride pipe

8

7

6

5

4

3

2

1

7

6

5

4

3

2

1

1200

0 S

teel

Cas

ing

2000

1000

BearingStratum

SoftStratum

1300

0 To

tal H

MP

leng

th

Drill bit

Steel CasingPipe

SteelCasingJoint

Deformed Bar

1000

1000

9000

Cas

ed U

pper

HM

P L

engt

h

20001000

1000⑥

1000

⑤

1000

④

1000

③

500

②

8000

Vinyl ChloridePipe

5600

①

Slip surface

Strain Gauge

H beam

500Baseine

Pressure GroutedHMP Bond Length

Non

-ste

el C

asin

g

This is an outline of the measurement piles.In this case, the vinyl chloride pipe with the strain gauges was set up in thesteel pipe.The strain gauges of installation sections are six places.

計測杭の概念図です。

高耐力マイクロパイルの場合、鋼管を削孔ケーシングとして用いますので、鋼管へひずみゲージを貼付することは不可能です。

そこで、塩ビ管にひずみゲージを貼付し、鋼管内に設置して計測しました。

ひずみゲージは、想定すべり面(5.6m)および最大曲げモーメントが発生すると予想される深度(2～3m)を考慮して６箇所に設置しました。

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Measurement position Measurement position in sectionin section

High Capacity MicropilesL=13.0-17.5m@1.5m

H beam

Measurement Piles

Measurement Piles

予備のスライドです。

使用しません。

非表示に設定しています。

計測杭の設置位置の断面図です。

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Measurement position Measurement position in ground plan

House of Inhabitant 林道

Construction position of High Capacity Micropiles

The Forestry Ro

Measurement Piles

No.6No.9

Tunneling

The field measurement was done by two places.They are the No.6 and No.9.In the following, the result of No.9 is introduced.

This figure shows the position of the measurement piles.The field measurement was done by two places.They are the No.6 and No.9.In the following, the result of No.9 is introduced.

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Bending Moment & Date (No.9)

-50

-40

-30

-20

-10

0

10

20

30

40

50

2/20 2/27 3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12

Date

Bendi

ng

Mom

ent(

kN・m

)

9-①

9-②

9-③

9-④

9-⑤

9-⑥

Date & Bending Moment Date & Bending Moment

Valley side

Mountain side

It was March 21 that the tunnel penetrated. The bending moment has increased in those days. The bending moment changed on March 27. After that, it indicates a constant value.

This figure shows the distribution of the date and the bending moment. It was March 21 that the tunnel penetrated.The bending moment has increased in those days. The bending moment changed on March 27.After that, it indicates a constant value.

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When we had the When we had the tunneling, the tunneling, the bending moment bending moment was an increasing was an increasing tendency. tendency. After the tunnel had After the tunnel had penetrated (3/21), penetrated (3/21), the bending moment the bending moment indicated a value indicated a value about half of the about half of the design.design.

No.9　Bending Moment Diagram

0

2

4

6

8

10

12

-80 -60 -40 -20 0 20 40 60 80

Bending Moment (kN・m)

Depth

(m)

2/21

3/20

3/27

4/6

4/26

5/6

Design Value

Slip Surface

Bending Moment DiagramBending Moment Diagram

Valley side Mountain side

This figure shows depth and the bending moment. When we had the tunneling, the bending moment was an increasingtendency. After the tunnel had penetrated (3/21), the bending moment indicated a value about half of the design.

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No.9　Axis force Diagram

0

2

4

6

8

10

12

-800 -600 -400 -200 0 200 400 600 800

Axis force(kN)

Depth

(m)

2/21

3/20

3/27

4/6

4/26

5/6

Slip Surface

Axis Force DiagramAxis Force DiagramThe change in the axial The change in the axial force is seen in the force is seen in the sliding surface.sliding surface.It might be an influence It might be an influence of the tunneling. of the tunneling. However, clear However, clear consideration is not consideration is not obtained. We will obtained. We will examine it in the future. examine it in the future.

Tension Compression

This figure shows depth and the axial force.The change in the axial force is seen in the sliding surface.It might be an influence of the tunneling. However, clear consideration is not obtained. We will examine it in the future.

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ConclusionConclusionThe bending moment has increased The bending moment has increased while digging the tunnel. while digging the tunnel. After the tunnel had penetrated, the After the tunnel had penetrated, the bending moment indicated half the bending moment indicated half the value of the design.value of the design.

It is thought that High Capacity It is thought that High Capacity MicropilesMicropiles are working as the control are working as the control piles.piles.

The bending moment has increased while digging the tunnel. After the tunnel had penetrated, the bending moment indicated half the value of the design. It is thought that HMP functions as a control works.

トンネルを掘削中の時は、曲げモーメントが増加した。

トンネル貫通後は、曲げモーメントは設計値の半分の値を示した。

HMPは抑止杭として機能していると考えられる。

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THE ENDTHE END

Thank you for your attention!!Thank you for your attention!!

Thank you.Thank you for your attention!!