104

10 1 0.1 0.01Particle Diameter, mm

0

20

40

60

80

100Pe

rcen

t Fin

er b

y W

eigh

t (%

)Ottawa Silica Sand (ASTM C-778)

Fig. 5.1. Grain size distribution of Ottawa sand

105

Fig. 5.2. Shear box of direct shear test device (after Wu, 1992)

106

15.00 15.50 16.00 16.50 17.00 17.50

Unit Weight, γ (kN/m3 )

25

30

35

40

45φ

(Deg

ree)

Air-Pluviation Sand

Compacted Sandφ = 6.43γ − 68.99

φ = 7.25γ − 79.51

Fig. 5.3. Relationship between unit weight γ and internal friction angle (after Chang, 2000)

107

(a)

(b)

Fig. 5.4. Soil hopper

Unit:mm

500

800

430

120

Slot Control HandleSlot Opening

Slot Opening Slot Control Handle

108

Fig. 5.5 Pluviation of the Ottawa sand into soil bin

Sand Hopper

SPT

Model Wall

Raining of Ottawa Sand

Steel Interface

Plate

109

1500

Unit: mm

SPT2

SPT1

Lift 1 SPT3

SPT4

Lift 2

SPT7

SPT5

SPT6

SPT8

SPT9

Ottawa SandLift 3

SPT10

SPT11

Lift 4

SPT13

SPT12

SPT14

150035Model Wall

Lift 5 SPT15

45

.

Side-view

300

300.

Fig. 5.6. Backfill compacted with square compactor in 5 lifts

α

110

1500

Unit: mm

Lift 2 SPT2

Lift 1 SPT1

Lift 3

Lift 4

SPT3

SPT4

Lift 7 SPT7

Lift 5

Lift 6

SPT5

SPT6

Lift 8

Lift 9

SPT8

SPT9

Ottawa Sand Lift 10

Lift 11

SPT10

SPT11

Lift 13

Lift 12

Lift 14

SPT13

SPT12

SPT14

150035Model Wall

Lift 15 SPT15

45

Side-view

100

100

Fig. 5.7. Backfill compacted with strip compactor in 15 lifts

α

111

6

5

4

3

2 .250

Lane 1

Orrawa Sand

Soil Compactor

Model Wall Soil Pressure Transducer

Steel Column

Top-view

Fig. 5.8. Backfill compacted with square compactor in 6 lanes

112

11

13

1514

12

9

7

5

3

1

10

8

6

4

2

Soil Compactor

.

Lnae

100

Ottawa Sand

Model Wall Soil PressureTransducer

Steel Column

Top-view

Fig. 5.9. Backfill compacted with strip compactor in 15 lances

113

Fig. 5.10. Soil-density control cup

unit : mm

Top-view

Side-view

Acrylic Tube

Acrylic Base Plate30

5

43

3.5

70

70

70

43

50

114

Fig. 5.11. Soil-density cup

115

Density cups

1990

Unit : mm

Stee

l col

umn

WallModel

1500

45 1500

Steel base plate

Elevation

35

Ottawa Sand

Walkway

215

Fig. 5.12. Soil density cups buried at the different elevations

116

Soil PressureTransducer

Steel Base Plate

Top-viewSteel Beam

Model Wall

Steel Column

Density Cup

SideWall Sidewall

Ottawa Sand

Fig. 5.13. Locations of soil density cups at same elevation

117

0 20 40 60 80 100Relative Density, Dr(%)

0

0.3

0.6

0.9

1.2

1.5E

leva

tion

(m)

This StudyChen (2002)

Air-PluviationOttawa SandDrop Height = 1.5 mSlot opening = 18 mm

Drop Height = 1.0 mSlot Opening = 15 mm

Fig. 5.14. Distribution of soil density for loose sand

118

(a) Compaction at H = 1.2 m (α = 60o)

(b) Compaction at H = 1.2 m (α = 60o)

Fig. 5.15. Compaction of backfill with square compactor

Vibratory Compactor Steel Interface Plate

Ottawa Sand

Model Wall

SPT

Ottawa Sand Vibratory Compactor

119

0 20 40 60 80 100Relative Density, Dr (%)

0

0.3

0.6

0.9

1.2

1.5E

leva

tion

(m)

This StudyChen, 2003

Compacted SandSquare Compactor Lift = 0.3 m

Fig. 5.16. Distribution of soil density compacted with square compactor

120

(a) Compaction at H = 1.1 m (α = 70o)

(b) Compaction at H = 1.1 m (α = 70o)

Fig. 5.17. Compaction of backfill with strip compactor

Acentric Motor

Steel Interface Plate

Vibratory Compactor

Model Wall

SPT

Ottawa Sand

Steel Interface Plate

Vibratory Compactor

Plastic Sheets

121

0 20 40 60 80 100Relative Density, Dr (%)

0

0.3

0.6

0.9

1.2

1.5E

leva

tion

(m)

Compacted SandStrip Compactor Lift = 0.5 m

0.1 m

Air-PluviatedLoose Sand(Dr = 31~39%)

Dense Sand

Fig. 5.18. Distribution of soil density compacted with strip compactor (Lift = 0.5 m)

122

0 20 40 60 80 100Relative Density, Dr (%)

0

0.3

0.6

0.9

1.2

1.5El

evat

ion

(m)

Compacted SandStrip CompactorLift = 0.1 m

Dr = 70%Air-PluviatedLoose Sand(Dr = 31~39%)

Dense Sand

Fig. 5.19. Distribution of soil density compacted with strip compactor (Lift = 0.1 m)

123

0 20 40 60 80 100Relative Density, Dr (%)

0

0.3

0.6

0.9

1.2

1.5E

leva

tion

(m) Strip Compactor

Square Compactor

Compacted Sand

Lift = 0.1 m(This Study)

Lift = 0.3 m (Chen, 2002)

Fig. 5.20. Comparison of density distribution compacted with strip and square compactors

124

Fig. 5.21. Relative density vs. Depth relation for vibratory

roller compaction (after D’Appolonia et al., 1969)

125

Fig. 5.22. Lubrication layer hung on the side wall

Lubrication Layer (Plastic Sheets)

Model Wall

126

Fig. 5.23. Schematic diagram of sliding block test (after Fang et al., 2004)

δ

Lubrication Layer

Handle

Standard Weight

Soil Box

Uplift Rod

Worm Gear

Horizontal LineN

T

F

27 mm

60 mm

Acrylic Plate

20 mm10 mm

Steel Plate

900 mm

600 mm

127

Fig. 5.24. Sliding block test apparatus (after Fang et al., 2004)

Standard weight↓

↙ Sliding plate↙ Soil boxPlastic sheet ↘

←

Ball bearing

Handle Worm gear

Uplift rod

128

1 10 100

Normal Stress, σ (kN/m2)

0

5

10

15

20

25Fr

ictio

n A

ngle

, δsw

(deg

ree)

Sliding Block TestPlastic-Sheet Method1 Thick + 2 Thin Sheeting

δsw = 7.5o

Fig. 5.25. Variation of interface angle with normal stress (after Fang et al., 2004)

129

(a)

(b) Smooth Steel Plate

Fig.5.26 Direct Shear Test Arrangement to Determinate Wall Friction Angle

Smooth Steel Plate

Unit : mm

130

15.5 15.75 16 16.25 16.5 16.75 17 17.25Unit Weight , γ (kN/m3)

8

9

10

11

12

13

14

15δ w

(deg

ree)

Test Data (air-pluviation)δw = 3.41γ - 43.69Test Data (compaction)δw = 3.08γ - 37.54

σn = 79.8 kN/m2Ottawa Sand

Fig. 5.27. Relationship between unit weight γand

wall friction angle δw (after Ho, 1999)

131

120

20

63

Dry Ottawa Sand

Steel Plate

Safety-Walk

N

5

Upper Shear Box

Unit : mm (a)

80

5

120

15

20

80

80

Unit : mm

Safety-Walk

(b)

Fig. 5.28. Direct shear test arrangement to determine interface friction angle

Anti-Slip MaterialSafety-Walk

132

15 16 17 18 19Unit Weight, γ (kN/m3)

10

15

20

25

30

35δ i

(deg

ree)

Air-Pluviation Snad

Compacted Sand

δi = 2.7 γ - 21.39

δi = 1.97 γ - 8.9

Ottawa Sandσn = 4.60 kN/m2

Fig. 5.29 Relationship between unit weight γ and interface plate friction

angle δi

133

15 15.5 16 16.5 17 17.5 18 18.5 19Unit Weight , γ (kN/m3)

0

5

10

15

20

25

30

35

40

45

Fric

tion

Ang

le (d

egre

e)

Internal Friction Angle, φ

φ = 6.43γ − 68.99 (Chang, 2000)

Steel-Plate Friction Angle, δi

δi = 2.7γ − 21.39

Model Wall Friction Angle, δw

δ w = 3.41γ − 43.69 (Ηο, 1999)

Sidewall Friction Angle, δswδsw = 7.5o (Fang et al., 2004)

Ottawa Sand(Air-Pluviated)

(a) Air-Pluviated Sand

(b) Compacted Sand

Fig. 5.30. Relationship between unit weight γ and

different friction angles

15 15.5 16 16.5 17 17.5 18 18.5 19Unit Weight , γ (kN/m3)

0

5

10

15

20

25

30

35

40

45

Fric

tion

Ang

le (d

egre

e)

Internal Frict

ion Angle, φ

φ = 7.25γ − 79.51 (C

hang, 2000)

Steel-Plate Interface Friction Angle, δi

δi = 1.97γ − 8.9

Model Wall Friction Angle, δw

δ w = 3.08γ − 37.54 (Ηο, 1999)

Sidewall Friction Angle, δswδsw = 7.5o (Fang et ai., 2004)

Ottawa Sand(Compacted)