behavior of sand after a high number of cycles application ... · behavior of sand after a high...
TRANSCRIPT
RESEARCH PAPER
Behavior of Sand After a High Number of Cycles Applicationto Shallow Foundation
Hanane Dob1 • Salah Messast1 • Abdelhamid Mendjel2 • Marc Boulon3 •
Etienne Flavigny3
Received: 21 March 2016 / Revised: 3 June 2016 / Accepted: 3 June 2016 / Published online: 17 June 2016
� Iran University of Science and Technology 2016
Abstract Considerable strains appear in the structures
during accumulation of the irreversible strains of the sub-
grade under the effect of the cyclic loads. If the number of
cycles is very large, even a small strain after accumulation
becomes significant and sometimes harmful. In this study,
a simple numerical modeling of the behavior of sand under
cyclic loading is proposed. The suggested approach con-
sists, in drained condition, in determining the parameters
characterizing the average cyclic path of the soil under the
effect of the number of cycles duly characterized and
translating the cyclic effect by a volumetric strain cumu-
lated by a variation of the module of the soil. In this study,
we are interested in cyclic triaxial compression tests sim-
ulated by a finite element calculation. While proposing an
analogy between the cyclic pseudo creep and the soft soil
creep model (SSCM), on the first hand we propose an
equivalence between the cyclic parameters and the
parameters of SSCM, and on the other an equivalence time
number of cycles will be established. The application of the
formulation suggested on a shallow foundation under
cyclic loading confirms the good adaptation of the model
suggested to this type of problem.
Keywords Cyclic loading � Plaxis � SSCM � Modeling �Volumetric strain � Sand � Shallow foundation
1 Introduction
Many structures are likely to be subjected to cyclic loading
in either normal or accidental situations such as roads,
bridges, railroads, silos, tanks, foundations for vibrating
machines, etc. However, the accumulation of the soil strain
causes disorders and even adverse effects in these structures
or the neighboring structures. Thus, the importance of pre-
dicting the accumulated irreversible cyclic strains appears.
There are two categories of approaches for the prediction of
the cyclic behavior of materials: the implicit and the explicit
approaches. The implicit or the incremental models require
several (hundreds) increments per cycle, which causes an
accumulation of the numerical error and an imprecision of
the results for a high number of cycles. Generally, this type
of model is desirable for N\ 50 [1]; therefore, the impor-
tance of the explicit models especially for a high number of
cycles (N[ 1000) appears, and in such models only one or a
few initial cycles are calculated by means of an incremental
calculation and the rest of the cycles will be treated as a
pseudo creep.
Several studies have been conducted in this theme and
their application on the response of the shallow founda-
tion under cyclic loading. Some researchers have focused
their work on the triaxial and shear cyclic tests with low
and high number of cycles [2–6]. Others are interested in
the constitutive modeling of the behavior of sand under
cyclic loading [7–11]. Several researchers are interested in
the numerical modeling of the problem [12–14] and others
have studied the response of the foundation under large
number of cycles [15–20].
& Salah Messast
Hanane Dob
1 Department of Civil Engineering, Laboratory LMGHU,
University of Skikda, Skikda, Algeria
2 Department of Civil Engineering, University of Annaba,
Annaba, Algeria
3 Laboratory 3s-r, University Joseph Fourier,
Saint-Martin-d’Heres, France
123
Int J Civ Eng (2016) 14:459–465
DOI 10.1007/s40999-016-0050-1
The objective of this paper is to study the behavior
of the pulverulent soils under cyclic loading and the
estimation of the accumulated volumetric strains, based
on an analogy between the soft soil creep model
(SSCM) and the cyclic pseudo creep, which assimilates
the latter as a deferred behavior of a fictitious material,
handled by a finite elements calculation using the Plaxis
program and taking the SSCM as a model of behavior
of the soil.
Moreover, this technique will be applied on a shallow
foundation under cyclic loading (centrifuge test of Helm
et al. [21]) to highlight the reliability of the proposed
formulation.
2 Cyclic Behavior
A cyclic triaxial test can be described by the cyclic stress
path in the p–q plane, where p is the mean pressure and q is
the deviatoric stress. Figure 1 shows the definition of cyclic
parameters in the p–q plane.
3 Presentation of Soft Soil Creep Model
The SSCM is a relatively new model that has been
developed for application to settlement problems of foun-
dations, embankments, and unloading.
The latter is most dominant in soft soils, and the
advantage of this model is that it takes into account the
viscous effect, creep and stress relaxation. Where all soils
exhibit some creep and primary compression, it is followed
by a certain amount of secondary compression.
In this approach, we consider that the pseudo creep (the
evolution of the strain according to time; see Fig. 2) is
controlled mainly by the effect of the stiffness parameters
of the SSCM.
The SSCM requires the following material constants:
• Failure parameters as in the Mohr–Coulomb model:
• u: friction angle (�).• c: cohesion (kN/m2).
• w: dilatancy angle (�).
• Basic stiffness parameters
• k*: the modified swelling index.
• j*: the modified compression index.
• l*: secondary compression index.
4 Analogy Between the Cyclic Pseudo Creepand SSCM
This section consists of reproducing the curves of the
volumetric strain as a function of the number of cycles by a
pseudo creep treated by analogy using SSCM.
Fig. 1 The cyclic stresses path in the p–q plane
Fig. 2 Response of the materials by the SSCM
Fig. 3 Evolution of strain in a cyclic triaxial test
460 Int J Civ Eng (2016) 14:459–465
123
In this approach, the pseudo creep is treated by analogy
as a behavior of a fictitious material by the SSCM (see
Fig. 3), the parameters k*, j* and l* were estimated
according to the cyclic parameters, and then we looked for
an equivalence between the time and the number of cycles.
Figure 3 shows the evolution of strain according to:
– time (t) in the case of the response of the fictitious
material by the SSCM;
– number of cycles (N) in the case of the cyclic pseudo
creep.
5 Numerical Application and Results
This work is based on the drained cyclic triaxial tests
realized by Thanopoulos [22] on the fine sand of Plancoet
characterized by its dry volume weight of 12.5 kN/m3,
u = 37.6�, c = 0 kN/m2, W = 6�, m = 0.2.
Ten (10) cyclic tests have been achieved to impose
stresses for three values of lateral stress (40, 80 and
160 kPa). The number of cycles varied from 200 to 2760
cycles, except for test 9, which contains only 23 cycles,
tests 4 and 14 contain two series of cycles (indications a
and b), and test 8 is a monotonic test at a lateral stress equal
to 80 kPa. The characteristics of the tests are shown in
Table 1.
c: Cohesion, W: dilatancy angle, u: friction angle, m:Poisson’s ratio.
Figure 4 shows in the p–q plane the band in which the
tests of Thanopoulos [22] was achieved.
After several numerical tests, the simulated and experi-
mental curves are shown in Fig. 5 with the parameter sets for
each test. Table 2 summarizes the parameters of the cyclic
tests of Thanopoulos [22] and the parameters of the SSCM
for the tests which present a conformity with the simulated
tests that is to say tests: 2, 4a, 12, 14a and 14b [12].
According to the curves in Fig. 5, there is a good con-
vergence between the simulated and experimental curves,
except that tests 2 and 4a show a slight gap between the
simulated and experimental curves, this gap is acceptable.
These two tests are located closer to the characteristic line
than other tests (see Fig. 4), which supports the basic idea
of this work. The equivalence between time number of
cycles is established as 1 day for one cycle.
Tables 1 and 2 show the parameters of fictitious mate-
rial. The procedure adopted is as follows: for constant
values of gav, the curves of k*, j* and l* according to Dg/gl
were traced, and from these curves Eq. (1) is written:
k� ¼ A1 �Dggl
þ B1
j� ¼ A2 �Dggl
þ B2
l� ¼ A3 �Dggl
þ B3:
ð1Þ
The resolution of the equations system (1) allows the
determination of Ai and Bi. The Ai and Bi dependence curves
according to gav allow to write the equations system (2):
A1 ¼ �55:531 � gav þ 50:001ð Þ � 10�5;
B1 ¼ �55:53 � gav � 50:0013ð Þ � 10�5;
A2 ¼ �55:53 � gav þ 50:0013ð Þ � 10�5;
B2 ¼ �20:795 � gav � 16:7622ð Þ � 10�5;
A3 ¼ �452:309 � gav þ 413:566ð Þ � 10�5;
B3 ¼ �172:553 � gav � 125:28ð Þ � 10�5 :
ð2Þ
After the substitution of Eq. (2) into Eq. (1), we can
express k*, j* and l*, respectively, by Eqs. (3)–(5):
Table 1 Parameters of the cyclic tests in compression achieved on
the fine sand of Plancoet, according to Thanopoulos [22]
Test r3 (kPa) N qmin (kPa) qmax (kPa) gav Dg
1 40 1670 4 89 0.837 1.18
2 40 2300 38 56 0.844 0.233
4a 80 406 9 166 0.801 1.118
4b 80 201 115 237 1.269 0.518
7 80 1274 67 166 0.980 0.571
8 80 1 0 0
9 80 23 116 172 1.125 0.823
11 40 2758 37 125 1.209 0.669
12 160 708 6 148 0.414 0.669
13 160 352 3 323 0.760 1.188
14a 160 256 37 154 0.497 0.514
14b 160 1045 37 250 0.69 0.812
16 160 1932 143 182 1.211 0.173
Fig. 4 Tests of Thanopoulos [22] with different average cyclic level
gav in the p–q plane. gl: the limit cyclic level, gc: the characteristic
cyclic level
Int J Civ Eng (2016) 14:459–465 461
123
k� ¼ Dggl
�555:31 � gavþ 500:01ð Þþ 207:96 � gav� 15:762
� �
� 10�5; ð3Þ
j�¼ Dggl
�555:3 �gavþ500:013ð Þþ207:951 �gav�167:622
� �
�10�5; ð4Þ
l� ¼ Dggl
�4523:09 � gav þ 4135:66ð Þ þ 1725:535 � gav�
� 1252:8� � 10�5: ð5Þ
The relationship between the parameters characterizing
the fictitious material and the cyclic parameters is defined
by Eqs. (3)–(5) [13].
The characterization of the fictitious material is defined
by the determination of the parameters: k*, j* and l*, andthe others parameters are supposed to be the same as those
of the real material.
6 FEM Calculation of Shallow Foundations UnderCyclic Loading
In the recalculation of the centrifuge model test of Helm
et al. [21] (strip foundation under cyclic loading) the same
set of parameter was used to calculate the settlement after a
large number of cycles [23]. The calculation of settlement
using the PLAXIS program is done after the calculation of
the parameters k*, j* and l* of SSCM with the proposed
formulations. With the aim of testing the reliability of the
proposed formulation, we proceed to the comparison
between results obtained by this method and those derived
from the test of Helm et al. [21] and those obtained by
Wichtmann [24].
The numerical simulations were performed by FEM
calculation, where the discretization was carried out by the
elements of 15 nodes. Our model has 7819 nodes and 955
elements.
In the centrifuge model test of Helm et al. [21], fine sand
was used (c = 27 kN/m3, u = 32.8�, W = 3�).The centrifuge model test was recalculated with the
following boundary conditions:
• Dimensions of the test container: width 18.1 m, height
7.3 m (prototype). Using the symmetry, only half of the
soil was discretized (9.05 m 9 7.3 m) Fig. 6.
• Foundation: width b = 1.0 m, height h = 0.6 m, depth
of embedding t = 0 m.
• Material of the foundation: aluminum with
weight = 27 kN/m3, E = 25 000 MPa and m = 0.3.
• The average load rav = 89 kPa, amplitude ramp =
75 kPa.
Determining the response of the foundation under cyclic
loading is effected by a model that replaces the cyclic
loading after a number of cycles by the application of the
cumulative volumetric strain of the surrounding soil after
the same number of cycles. The soil mass is discretized in
several regions. The stresses developed in each region after
a loading cycle defined the parameters of an equivalent
triaxial test. These parameters determine later cyclical
parameters of each region. The behavior of the global
model will be determined by the application cumulative
strains of each region.
Figure 7 shows the cyclic loading fields applied in dif-
ferent regions of the soil in the p–q plane in terms of
average cyclical level.
Figure 8 shows that the evolution of settlement of the
shallow foundation presented in this study is very similar to
Table 2 Parameters of the
triaxial cyclic tests in
compression carried out by the
fine sand of Plancoet [22], and
the parameters of the simulated
tests of SSCM
Test r3 (kPa) qav (kPa) gav Dg k* j* l*
2 40 47 0.844 0.233 2.00E-04 1.00E-04 2.30E-03
4a 80 87 0.801 1.118 4.50E-04 3.50E-04 4.70E-03
12 160 77 0.414 0.669 4.50E-04 3.500E-04 4.40E-03
14a 160 96 0.497 0.514 2.00E-04 1.00E-04 2.30E-03
14b 160 143 0.69 0.812 4.50E-04 3.50E-04 3.50E-03
462 Int J Civ Eng (2016) 14:459–465
123
Fig. 5 Curves (ev–N) simulated and experimental according to Thanopoulos [22]
Int J Civ Eng (2016) 14:459–465 463
123
experimental curves of Helm et al. [21] and that numerical
calculation by Wichtmann [25].
7 Conclusion
The estimation of the evolution of the accumulated volu-
metric strain is formulated by an analogy between the
cyclic pseudo creep and the behavior of a fictitious mate-
rial, according to the SSCM behavior.
In this approach, the mechanical characteristics of the
fictitious material (k*, j* and l*) are determined according
to the cyclic parameters (gl, gav and Dg).The equivalence between time (SSCM) and the number
of cycles (cyclic pseudo creep) is set as per 1 day for one
cycle; it means that the modeling of cyclic behavior after
105 cycles can be simulated by the response of a fictitious
material with SSCM for a fictitious time (105 days).
The comparison between the proposed method and those
derived from the centrifuge model test of Helm et al. [21]
and those obtained by Wichtmann [24] confirms a good
adaptation of the proposed model for this type of problem.
References
1. Wichtmann T (2005) Explicit accumulation model for non-co-
hesive soils under cyclic loading. Dissertation, University of
Bochum
2. Katzenbach R and Festag G (2004) Material behaviour of dry
sand under cyclic loading. Cyclic behaviour of soils and lique-
faction phenomena. In: Proceedings of CBS04, Balkema,
pp 153–158
3. Dash HK, Sitharam TG (2011) Cyclic liquefaction and pore
pressure response of sand-silt mixturs. Geomech Eng
3(2):83–108
4. Hyodo M, Hyde AFL, Aramaki N, Nakata Y (2002) Undrained
monotonic and cyclic shear behaviour of sand under low and high
confining stresses. Soils Found 42(3):63–76
5. Wichtmann T, Triantafyllidis Th (2004) Influence of a cyclic and
dynamic loading history on dynamic properties of dry sand. Part
I: cyclic and dynamic torsional prestraining. Soil Dyn Earthq Eng
24(2):127–147
6. Suriyavut R (2013) Behaviour of soil-structure interfaces sub-
jected to a large number of cycles. Application to piles. Disser-
tation, University of Grenoble
7. Marr WA, Christian JT (1981) Permanent displacements due to
cyclic wave loading. J Geotech Eng Div ASCE
107(GT8):1129–1149
8. Bouskovalas G, Whitman RV, Marr WA (1984) Permanent dis-
placement of sand with cyclic loading. J Geotech Eng
110(11):1606–1623
9. Sawicki A, Swidzinski W (1987) Compaction curve as one of
basic characteristics of granular soils. In: Proceedings of the
fourth symposium Franco-Polish soil mechanics applied,
Grenoble
10. Niemunis A, Wichtlann T, Triandatafyllidis Th (2005) A high-
cycle accumulation model for sand. Comput Geotech 32:245–263
11. Triantafyllidis T, Wichtmann T and Niemunis A (2004) The
determination of cyclic strain history. Cyclic behaviour of soils
and liquefaction phenomena. In: Balkema, international confer-
ence, Bochum, pp 321–334
Fig. 7 Simulated tests with different average cyclic level gav in the
p–q plane
Fig. 8 Comparison of the settlement curves S (N) of the centrifuge
model test and the FEM calculation
Fig. 6 Geometry of the centrifuge test (prototype)
464 Int J Civ Eng (2016) 14:459–465
123
12. Messast S, Boulon M, Flavigny E, Labnieh S (2008) Modelisa-
tion constitutive du comportement cyclique des sables en con-
dition drainee. Studia Geotechnica et Mechanica 1–2:131–143
13. Dob H, Messast S, Boulon M, Flavigny E (2013) Analogie entre
le pseudo fluage cyclique et le modele SSCM pour la formulation
explicite des deformations volumiques sous grand nombre de
cycles. 3eme Conference Maghrebine en Ingenierie Geotech-
nique, Alger
14. Shariati M, Hatami H, Epakchi HR (2012) Experimental and
numerical investigations on the ratcheting characteristics of
cylindrical shell under cyclic axial loading. Struct Eng Mech
44(6):753–762
15. Sawicki A, Swidzinski W, Zadroga B (1998) Settlement of
shallow foundations due to cyclic vertical force. Soil Found
38(1):35–43
16. Shamoto Y, Sato M, Zhang JM (1996) Simplified estimation of
earthquake-induced settlements in saturated sand deposits. Soils
Found 36(1):39–50
17. Fathi MO, Vanapalli K, Saatcioglu M (2013) Generalized Sch-
mertmann equation for settlement estimation of shallow footings
in saturated and unsaturated sands. Geomech Eng 5(4):343–362
18. Holzlohner U (1984) Settlement of shallow foundations on sand.
Soils Found 24(4):58–70
19. Kim T, You S (2015) Settlement analysis considering sand mat
induced initial settlement in soft ground improved by PBD. IJCE
13(2):146–152
20. Lotfizadeh MR, Kamalian M (2016) Estimating bearing capacity
of strip footings over two-layered sandy soils using the charac-
teristic lines method. IJCE 14(2):106–116
21. Helm J, Laue J, Ttiantafyllidis T (2000) Untersuchungen an der
RUB zur Verformungs entwicklung von Boden unter zyklischen
Beanspruchungen. Boden unter fast zyklischer Belastung:
Erfahrungen und Forschungsergebnisse. Lehrstuhl fur Grundbau
und Bodenmechanik, Ruhr-Universitat Bochum, pp 109–33
22. Thanopoulos I (1981) Contribution a l’etude du comportement
cyclique des milieux pulverulents. These, Universite Scientifique
et medicale & l’institut national polytechnique de Grenoble
23. Niemunis A, Wichtmann T, Petryna Y, Ttiantafyllidis T (2005)
Stochastic modelling of settlements due to cyclic loading for
soil–structure interaction. In: Structural safety and reliability, 9th
international conference, ICOSSAR
24. Wichtmann T, Niemunis A, Ttiantafyllidis T (2004) The effect of
volumetric and out-of-phase cyclic loading on strain accumula-
tion. In: Cyclic behaviour of soils and liquefaction phenomena,
Balkema. International conference in Bochum, pp 247–56
25. Wichtmann T, Niemunis A, Ttiantafyllidis T (2005) Strain
accumulation in sand due to cyclic loading: drained cyclic tests.
Soil Dyn Earthq Eng 25:967–979
Int J Civ Eng (2016) 14:459–465 465
123