Tunnel construction remain a challenging engineering project, even with the foremost progress in tunnel boring technology & tunnel design and one of the main problems from geotechnical point of view, is the intrinsic complexity and heterogeneity of soil. Indeed, tunnel design requires an excellent knowledge of soil characteristics. But it’s not possible to identify the soil parameters at each point. It is therefore, important to evaluate which soil parameters are the most determinant and how the variability of soil properties can influence the tunnel. Hence, a parametric study is performed by using the finite element code Plaxis, in order to investigate, how the fluctuation of fundamental soil parameters can affect the ground movements induced by tunnel construction. The parametric study reveals that the effect of fluctuation of the cohesion and the friction angle is more important than the effect of the Young’s modulus. While the effect of fluctuation of the Poisson’s ratio is negligible. On the other hand, the results obtained indicate that, the settlement is more sensitive to cohesion compared to friction angle, but in term of horizontal displacements the two parameters have the same effect

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International Journal of Civil Engineering and Technology (IJCIET)
Volume 8, Issue 1, January 2017, pp.
Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1
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© IAEME Publication Scopus
STUDY OF THE EFFECT
THE FUNDAMENTAL SOIL
GROUND MOVEMENTS IND
ERSIM Laboratory, Mohammadia Engineering School,
Mohammed V University, Rabat, Morocco
ERSIM Laboratory, Mohammadia Engineering School,
Mohammed V University, Rabat, Morocco
ERSIM Laboratory, Mohammadia
Mohammed V University, Rabat, Morocco
ABSTRACT
Tunnel construction remain a challenging engineering project, even with the foremost
progress in tunnel boring technology & tunnel design and one of the main problems from
geotechnical point of view, is the intrinsic complexity and heterogeneity of soil.
Indeed, tunnel design requires an excellent knowledge of soil characteristics. But it’s not
possible to identify the soil parameters at each point.
which soil parameters are the most determinant and how the variability of soil properties can
influence the tunnel.
Hence, a parametric study is performed by using the finite element code Plaxis, in order to
investigate, how the fluctuation of fundamental
movements induced by tunnel construction.
The parametric study reveals that the effect of fluctuation of the cohesion and the friction
angle is more important than the effect of the Young’s modulus. While the effect
of the Poisson’s ratio is negligible.
On the other hand, the results obtained indicate that, the settlement is more sensitive to
cohesion compared to friction angle, but in term of horizontal displacements the two
parameters have the same effect
Key words: Tunnel, Numerical Model, Parametric Study, Settlement,
Displacements, Fundamental Soil Parameters
IJCIET/index.asp 911
International Journal of Civil Engineering and Technology (IJCIET)
Volume 8, Issue 1, January 2017, pp. 911–919 Article ID: IJCIET_08_01_107
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1
6308 and ISSN Online: 0976-6316
Scopus Indexed
STUDY OF THE EFFECT OF FLUCTUATION OF
THE FUNDAMENTAL SOIL PARAMETERS ON
GROUND MOVEMENTS INDUCED BY TUNNEL
CONSTRUCTION
Nouaman Tafraouti
ERSIM Laboratory, Mohammadia Engineering School,
Mohammed V University, Rabat, Morocco
Rhali Benamar
ERSIM Laboratory, Mohammadia Engineering School,
Mohammed V University, Rabat, Morocco
Nouzha Lamdouar
ERSIM Laboratory, Mohammadia Engineering School,
Mohammed V University, Rabat, Morocco
Tunnel construction remain a challenging engineering project, even with the foremost
progress in tunnel boring technology & tunnel design and one of the main problems from
point of view, is the intrinsic complexity and heterogeneity of soil.
Indeed, tunnel design requires an excellent knowledge of soil characteristics. But it’s not
possible to identify the soil parameters at each point. It is therefore, important to evaluate
which soil parameters are the most determinant and how the variability of soil properties can
Hence, a parametric study is performed by using the finite element code Plaxis, in order to
investigate, how the fluctuation of fundamental soil parameters can affect the ground
movements induced by tunnel construction.
The parametric study reveals that the effect of fluctuation of the cohesion and the friction
angle is more important than the effect of the Young’s modulus. While the effect
of the Poisson’s ratio is negligible.
n the other hand, the results obtained indicate that, the settlement is more sensitive to
cohesion compared to friction angle, but in term of horizontal displacements the two
ffect
Numerical Model, Parametric Study, Settlement,
Displacements, Fundamental Soil Parameters.
editor@iaeme.com
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1
OF FLUCTUATION OF
PARAMETERS ON
UCED BY TUNNEL
ERSIM Laboratory, Mohammadia Engineering School,
ERSIM Laboratory, Mohammadia Engineering School,
Engineering School,
Tunnel construction remain a challenging engineering project, even with the foremost
progress in tunnel boring technology & tunnel design and one of the main problems from
point of view, is the intrinsic complexity and heterogeneity of soil.
Indeed, tunnel design requires an excellent knowledge of soil characteristics. But it’s not
It is therefore, important to evaluate
which soil parameters are the most determinant and how the variability of soil properties can
Hence, a parametric study is performed by using the finite element code Plaxis, in order to
soil parameters can affect the ground
The parametric study reveals that the effect of fluctuation of the cohesion and the friction
angle is more important than the effect of the Young’s modulus. While the effect of fluctuation
n the other hand, the results obtained indicate that, the settlement is more sensitive to
cohesion compared to friction angle, but in term of horizontal displacements the two
Numerical Model, Parametric Study, Settlement, Horizontal

2. Study of The Effect of Fluctuation of The Fundamental Soil Parameters On Ground Movements Induced by Tunnel
Construction
http://www.iaeme.com/IJCIET/index.asp 912 editor@iaeme.com
Cite this Article: Nouaman Tafraouti, Rhali Benamar and Nouzha Lamdouar, Study of The
Effect of Fluctuation of The Fundamental Soil Parameters On Ground Movements Induced by
Tunnel Construction. International Journal of Civil Engineering and Technology, 8(1), 2017,
pp. 911–919.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1
1. INTRODUCTION
In the past three decades, tunnel construction has been considerably expanded to meet the accelerated
urbanization process with an increasing use of the underground space for transportation infrastructures
and other facilities like water supply and sewage systems.
This increase of tunnel construction is promoted by two main factors:
The improvement of tunnel design with the recent advances of numerical computing resources and
the progress of tunnel boring technology, which make tunnel construction more advantageous in
techno-economic point of view.
On the other hand, tunnel solution give several benefits, in particular: Avoiding traffic disruption
in congested towns when tunnel is constructed and the reduction of negative environmental impact.
Indeed, contrary to other kinds of infrastructure, tunnels match with the growing environmental
awareness by providing appreciable ecological benefits with the limitation of negative impact on the
natural environment, the protection of areas of ecological value inside towns and the substantial
reduction of noise pollution.
Nevertheless, tunnel design remain complicated. In crowded towns, tunnel construction influence
the buildings in surface including old and sensitive structures and can induce serious damage to the
overlying buildings which can lead to repair cost and consequently to an increase of the cost of
project. Also, the subsurface space become more and more congested with the underground cables and
pipes which lead to a problems of interaction with the tunnel project.
But one of the fundamental problems which can affect the tunnel design, is the fluctuation of soil
properties. Indeed, soil is a complex material formed by weathering, erosion and sedimentation
processes. This material have been subjected to various stresses, physical and chemical changes.
Hence, soil is a highly non linear material which is characterized by his intrinsic heterogeneity and the
spatial variability of his properties.
For this reason, a parametric study is conducted in this paper, to assess the influence of soil
properties fluctuation on ground movements induced by tunneling.
This parametric study focused on four key soil parameters: The Young’s modulus, the Poisson’s
ratio, the cohesion and the friction angle.
The effect of variation of these parameters is analyzed in term of magnitude of ground movements
due to tunnel construction, namely, the surface settlement and the horizontal displacements.
The choice of studying the impact of soil properties fluctuation on the magnitude of ground
movements is justified by the fact that, the evaluation of the magnitude of ground movements due to
tunneling is a key issue in urban environments (Mair 1998) [1] because surface settlement may
damage adjacent structures (Clarke and Laefer 2014) [2] and also building damage can arise from
horizontal ground displacements (Moller 2006) [3].

3. Nouaman Tafraouti, Rhali Benamar and Nouzha Lamdouar
http://www.iaeme.com/IJCIET/index.asp 913 editor@iaeme.com
Figure 1 Settlement and horizontal soil displacement due to tunnel construction (After Loganathan 2011 [4])
2. PRESENTATION OF THE PROBLEM UNDER CONSIDERATION
The tunnel have a circular section, with a diameter D = 6m, a depth Z0 = 15m from surface to tunnel
springlines.
The soil have the following properties:
Table 1 Soil properties
Unit weight Young’s
Modulus
Cohesion
Internal friction
angle
Poisson’s
ratio
ϒ =20 kN/m3
E=35 Mpa c=70 Kpa ϕ =20° ν=0,3
3. METHODOLOGY
Numerical simulation is performed by means of the finite element code Plaxis 2D. Two dimensional
numerical simulation is adopted, because 2D models are largely adopted in the literature for modeling
tunnel construction, which is confirmed by several authors like Law 2012 [5] and Katebi et al 2013
[6].
In order to performed the parametric study, 11 numerical models are carried out by using the FEM
code Plaxis 2D.
The soil behavior is modeled by an elastic perfectly-plastic constitutive relation based on the
Mohr–Coulomb criterion, which is widely used for the numerical simulation of tunnels.
In the model of Mohr Coulomb, the main variables in characterizing the soil behavior are: The
cohesion, the friction angle, the Poisson’s ratio and the Young’s Modulus, which reflect the general
behavior of ground. The figure below presents the typical 2D finite element mesh used in numerical
analysis.
Uz :
Ux : Horizontal

4. Study of The Effect of Fluctuation of The Fundamental Soil Parameters On Ground Movements Induced by Tunnel
Construction
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Figure 2 Typical numerical model adopted for the simulation
4. RESULTS AND DISCUSSION
Tunnel excavation disturb the surrounding ground and generate ground movements as shown in the
figure below.
Figure 3 Contour of ground movements induced by tunneling in the reference case
The profile of surface settlement, obtained by the numerical model, for the reference case, is
reported in the figure below:

5. Nouaman Tafraouti, Rhali Benamar and Nouzha Lamdouar
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Figure 4 Profile of surface settlement
The figure below show for the reference case, the profile of horizontal soil displacements at
different distance from the tunnel axis, in the left side of the model.
Figure 5 Horizontal soil displacements at different distance from tunnel axis
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
-100 -80 -60 -40 -20 0 20 40 60 80 100
Distance from
centreline (m)
Settlement (mm)
Surface settlement
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-5 0 5 10 15 20 25 30 35 40 45
Depth from
surface (m)
Horizontal soil displacements (mm)
Horizontal soil displacements at 20m from tunnel axis
Horizontal soil displacements at 15m from tunnel axis
Horizontal soil displacements at 5m from tunnel axis
Horizontal soil displacements at 12m from tunnel axis
Horizontal soil displacements at 8m from tunnel axis
Horizontal soil displacements at 6m from tunnel axis

6. Study of The Effect of Fluctuation of The Fundamental Soil Parameters On Ground Movements Induced by Tunnel
Construction
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4.1. Influence of Poisson’s ratio
The analysis of the effect of Poisson’s ratio fluctuation on ground movements magnitude is reported in
the table below
Table 2 Effect of variability of Poisson’s ratio on ground movements magnitude
Poisson’s
ratio ν
Deviation
from
reference case
Maximum
surface
settlement (mm)
Deviation
from
reference case
Max magnitude of
horizontal
displacement (mm)
Deviation
from
reference case
0,1 -66,6% 41,57 +8,2% 69,57 -5,1%
0,2 -33,3% 39,85 +3,7% 71,27 -2,8%
0,3 0% 38,41 0% 73,32 0%
0,4 +33,3% 37,49 -2,4% 74,91 +2,2%
0,45 +12,5% 37,11 -3,4% 75,11 +2,4%
The results are reported in the graphs below:
Figure 6 Influence of the fluctuation of Poisson’s ratio on maximum surface settlement
0
5
10
15
20
25
30
35
40
45
50
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Maximummagnitudeofsurfacesettlement
Smax(mm)
Poisson's ratio ν

7. Nouaman Tafraouti, Rhali Benamar and Nouzha Lamdouar
http://www.iaeme.com/IJCIET/index.asp 917 editor@iaeme.com
Figure 7 Influence of the fluctuation of Poisson’s ratio on maximum magnitude of horizontal soil displacement
As shown in figures above, the increase of Poisson’s ratio results in a slight decrease of the
magnitude of surface settlement. On the other hand, the increase of the value of Poisson’s ratio is
accompanied by a small increase of the magnitude of horizontal soil displacements. Hence, the
influence of Poisson's ratio on the magnitude of ground movements seems negligible.
4.2. Influence of friction angle fluctuation
Table 3 Effect of variability of friction angle on ground movements magnitude
Friction
angle ϕ
(°)
Deviation
from
reference case
Maximum
surface
settlement (mm)
Deviation
from
reference case
Max magnitude of
horizontal
displacement (mm)
Deviation
from
reference case
18 -10% 44,87 +16,8% 86,91 +18,5%
20 0% 38,41 0% 73,32 0%
22 +10% 33,90 -11,7% 62,73 -14,4%
4.3. Influence of cohesion fluctuation
Table 4 Effect of variability of cohesion on ground movements magnitude
Cohesion
c (kpa)
Deviation
from
reference case
Maximum
surface
settlement (mm)
Deviation
from reference
case
Max magnitude of
horizontal
displacement (mm)
Deviation
from reference
case
63 -10% 48,73 +26,9% 88,35 +20,5%
70 0% 38,41 0% 73,32 0%
77 +10% 31,80 -17,2% 63,23 -13,76%
0
10
20
30
40
50
60
70
80
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Maximummagnitudeofhorizontal
soildisplacement(mm)
Poisson's ratio ν

8. Study of The Effect of Fluctuation of The Fundamental Soil Parameters On Ground Movements Induced by Tunnel
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4.4. Influence of Young’s Modulus fluctuation
Table 5 Effect of variability of Young’s Modulus on ground movements magnitude
Young’s
Modulus
E (Mpa)
Deviation from
reference case
Maximum surface
settlement (mm)
Deviation from
reference case
Max magnitude of
horizontal displacement
(mm)
Deviation from
reference case
31,5 -10% 42,66 +11,06% 81,46 +11,10%
35 0% 38,41 0% 73,32 0%
38,5 +10% 34,90 -9,14% 66,65 -9,09
The results of the analysis are shown in the figures below:
Figure 8 Influence of the fluctuation of cohesion "c”, friction angle "φ", Young’s Modulus "E" on maximum
surface settlement Smax
Figure 9 Influence of the fluctuation of cohesion "c”, friction angle "φ", Young’s Modulus "E" on maximum
horizontal displacement Vmax
It can be clearly seen from the figures above that the variation of each of the parameters (cohesion,
friction angle, Young’s Modulus) modify the magnitude of both surface settlement and horizontal soil
displacement.
-30
-20
-10
0
10
20
30
-15 -10 -5 0 5 10 15
Deviation of the
maximum surface
settlement from
reference case (%)
Deviation of the parameter
from his reference value (%)
ΔSmax = f (Δφ)
ΔSmax = f (Δc)
ΔSmax = f (ΔE)
-30
-20
-10
0
10
20
30
-15 -10 -5 0 5 10 15
Deviation of the
maximum horizontal
displacement from
reference case (%)
Deviation of the parameter
from his reference value (%)
ΔVmax = f (Δφ)
ΔVmax = f (Δc)
ΔVmax = f (ΔE)

9. Nouaman Tafraouti, Rhali Benamar and Nouzha Lamdouar
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The increase of this parameters leads to a reduction of the magnitude of ground movements and
vice versa.
The figures also show the leading influence of the cohesion and the friction angle on the
magnitude of ground movements compared to the effect of Young’s Modulus.
Also, it is interesting to note that in terms of magnitude of maximum surface settlement, the
influence of cohesion seems more significant than the friction angle. However the sensitivity of the
magnitude of maximum horizontal soil displacement is nearly identical for these two parameters.
In addition, the results obtained suggest that it is very important to take into account the fluctuation
of cohesion and friction angle of soil when evaluating the magnitude of ground movement’s induced
by tunneling and consequently in tunnel design.
5. CONCLUSION
In order to investigate the effect of fluctuation of soil properties on ground movements induced by
tunnel construction, a parametric study was performed through numerical modeling by using the FEM
code Plaxis. This parametric study focused on four key soil parameters, namely, the cohesion, the
friction angle, the Poisson’s ratio and the Young’s Modulus. The effect of variation of these
parameters, is analyzed in terms of magnitude of ground movements induced by tunneling,
specifically, the surface settlement and the horizontal displacement. The results obtained revealed that
the influence of Poisson's ratio fluctuation on the magnitude of ground movements can be neglected.
Nevertheless, any fluctuation of the cohesion, the friction angle or the Young’s Modulus modify
the magnitude of ground movements. The results also show, that magnitude of ground movements are
more sensitive to the cohesion and the friction angle than the Young’s Modulus. On the other hand, in
terms of maximum surface settlement, the influence of cohesion is more significant than friction angle.
However, the sensitivity of the maximum horizontal soil displacement is nearly identical for cohesion
and friction angle.
REFERENCES
[1] Mair, R.J., 1998. Recent experiences of tunnelling and deep excavations in London. Proceedings of
Fourth International Conference on Case Histories in Geotechnical Engineering, Missouri, pp.1193-
1206.
[2] Clarke, J.A., Laefer, D.F., 2014. Evaluation of risk assessment procedures for buildings adjacent to
tunnelling works. Tunnelling and Underground Space Technology 40, 333–342.
[3] Moller, S., 2006. Tunnel induced settlements and structural forces in linings. PhD Thesis.
University of Stuttgart.
[4] Loganathan, N., 2011. An innovative method for assessing tunnelling-induced risks to adjacent
structures. Published by Parsons Brinckerhoff Inc.
[5] Law, R.H.C., 2012. Effect of Existing Building on Tunneling-induced Ground Movements. Master
Thesis. Massachusetts Institute of Technology.
[6] Katebi, H., Rezaei, A.H., Bonab, M.H., 2013. The influence of surface buildings and ground
stratification on lining loads applying the finite element method. Electronic Journal of Geotechnical
Engineering 18, 1845-1861.
[7] Kim.H.J.,1997. Estimation for Tunnel Lining Loads. PhD Thesis. University of Alberta.
[8] Raghavendra V, Stanley Jose, G.H Arjun Shounak and Dr. T.G Sitharam, Finite Element Analysis
of Underground Metro Tunnels. International Journal of Civil Engineering and Technology, 6(2),
2016, pp. 6–15.
[9] Xie, X., Yang, Y., Ji, M., 2016. Analysis of ground surface settlement induced by the construction
of a large-diameter shield-driven tunnel in Shanghai. Tunnelling and Underground Space
Technology 51, 120–132.