Homogeneous halfspace
Dynamic soil characteristics (Horstwalde)
Layer
Halfspace
Cs
[m/s]
250
Cp
[m/s]
1470
βs
[−]
0.025
βp
[−]
0.025
ρ
[kg/m3 ]
1945
ν
[−]
0.485
Vertical displacement and corresponding IL at 25 Hz
Insertion loss [dB]
P. Coulier & A. Dijckmans, KU Leuven
15
Homogeneous halfspace
Wave impeding effect due to longitudinal bending stiffness
• Longitudinal bending waves with bending around x-axis are not excited due to limited width
• Longitudinal bending waves with bending around z -axis do not play a role due to low bending
stiffness
z
x
y
P. Coulier & A. Dijckmans, KU Leuven
16
Homogeneous halfspace
Wave impeding effect due to longitudinal bending stiffness
• Longitudinal bending waves with bending around x-axis are not excited due to limited width
• Longitudinal bending waves with bending around z -axis do not play a role due to low bending
stiffness
z
x
y
Wave impeding effect due to reflection of Rayleigh waves
• When the depth of the wave barrier is large enough compared to the Rayleigh wave length
• Rule of thumb: d > 0.75λR
• Almost independent of angle of incidence
P. Coulier & A. Dijckmans, KU Leuven
16
Furet test site
Dynamic soil characteristics
• Geotechnical and geophysical surveys
• Soil profile
h
[m]
2.0
10.0
∞
Layer
1
2
Halfspace
P. Coulier & A. Dijckmans, KU Leuven
Shear wave velocity [m/s]
50
100
150
200
Cp
[m/s]
375
290
490
βs
[−]
0.025
0.025
0.025
250
0
2
2
4
4
6
6
8
8
Depth [m]
Depth [m]
0
Cs
[m/s]
154
119
200
10
10
12
12
14
14
16
16
18
18
20
20
17
βp
[−]
0.025
0.025
0.025
ρ
[kg/m3 ]
1800
1850
1710
Dilatational wave velocity [m/s]
100
200
300
400
500
ν
[−]
0.40
0.40
0.40
Furet test site
Fundamental Rayleigh wave
Horizontal component
0
0
5
5
10
10
• Real (solid line) and imaginary
Depth [m]
Depth [m]
(dashed-dotted line) part of the
fundamental Rayleigh wave at 5 Hz
15
15
20
20
25
0
Displacement [−]
1
0
5
5
10
10
15
15
20
20
25
18
25
0
Depth [m]
(dashed-dotted line) part of the
fundamental Rayleigh wave at 25 Hz
−1
−1
0
Displacement [−]
1
Depth [m]
• Real (solid line) and imaginary
P. Coulier & A. Dijckmans, KU Leuven
Vertical component
−1
0
Displacement [−]
1
25
−1
0
Displacement [−]
1
Furet test site
• Vertical insertion loss for a 12 m deep sheet pile wall at 5 Hz (left) and 25 Hz (right)
• Vertical insertion loss for a 18 m deep sheet pile wall at 5 Hz (left) and 25 Hz (right)
Insertion loss [dB]
P. Coulier & A. Dijckmans, KU Leuven
19
Furet test site
Vertical insertion loss for a line load
10
8m
Insertion loss [dB]
Insertion loss [dB]
10
5
0
−5
−5
4
8
16
31.5
1/3 octave band center frequency [Hz]
P. Coulier & A. Dijckmans, KU Leuven
x
0
10
Insertion loss [dB]
Insertion loss [dB]
0
z y
4
8
16
31.5
1/3 octave band center frequency [Hz]
32m
5
5
−5
4
8
16
31.5
1/3 octave band center frequency [Hz]
10
16m
64m
5
0
−5
4
8
16
31.5
1/3 octave band center frequency [Hz]
20
depth 12 m
− − − depth 18 m
Conclusions and outlook
Conclusions
• Two phenomena contribute to the vibration reduction efficiency of a stiff wave barrier:
– interaction between Rayleigh waves in the soil and bending waves in the barrier
(jet grouting wall)
– reflections of the Rayleigh waves if the barrier depth is large compared to the Rayleigh
wavelength (sheet piling wall)
Outlook
• Comparison between simulations and measurements (jet grouting wall and sheet piling wall)
• A design guide with practical recommendations (RIVAS Deliverable D4.6) will be made publicly
available
P. Coulier & A. Dijckmans, KU Leuven
21
Thank you for your attention
Visit our website www.rivas-project.eu
P. Coulier & A. Dijckmans, KU Leuven
22