18
1735-0522
264
Seismic Geotechnique
Effect of bedrock inclination on seismic slope stability according to Iran seismically data
Miraboutalebi
M.
^{
b
}
Askari
F.
^{
c
}
Farzaneh
O.
^{
d
}
^{
b
}International Institute of Earthquake Engineering and Seismology
^{
c
}International Institute of Earthquake Engineering and Seismology
^{
d
}University of Tehran
1
12
2011
9
4
247
254
25
08
2009
19
11
2015
In this paper, the effect of bedrock inclination on seismic performance of slopes is investigated. The study was conducted based
on dynamic analysis of different slopes, evaluation of the earthquake acceleration in sliding mass, and calculating the
permanent displacement of the slope, using Newmark sliding block. The investigation indicates that variation of the bedrock
inclination may cause the acceleration magnitude and the displacement in the sliding mass to reach to their maximum level.
This may happen in conditions that the mean period of the acceleration time history on failure surface (Tmt) and the
predominant period of the slope (Ts ) are close to each other. Typical results are presented and discussed. A two dimensional
model of a typical slope was considered and conducting dynamic analyses, the slope performance was studied for different
geometries, strength parameters and shear wave velocities. Such a performance has been studied by assessing the record of
acceleration in sliding mass (the mass above the critical sliding surface) and calculating the slope displacement using Newmark
method. It is shown that neglecting the effect of bedrock inclination, would lead to non-real results in assessing the seismic slope
performance.
302
Seismic Geotechnique
Low-amplitude dynamic properties for compacted sand-clay mixtures
Hassanipour
A.
^{
e
}
Shafiee
A.
^{
f
}
Jafari
M.K.
^{
g
}
^{
e
}International Institute of Earthquake Engineering and Seismology
^{
f
}International Institute of Earthquake Engineering and Seismology
^{
g
}International Institute of Earthquake Engineering and Seismology
1
12
2011
9
4
255
264
14
10
2009
19
11
2015
Shear modulus and damping ratio are important input parameters in dynamic analysis. A series of resonant column tests was
carried out on pure clays and sand-clay mixtures prepared at different densities to investigate the effects of aggregate content,
confining stress, void ratio and clay plasticity on the maximum shear modulus and minimum damping ratio. Test results revealed
an increase in the maximum shear modulus of the mixture with the increase in sand content up to 60%, followed by a decrease
beyond this value. It was also found that the maximum shear modulus increases with confining stress, and decreases with void
ratio. In addition, minimum damping ratio increases with sand content and clay plasticity and decreases with confining stress.
Finally, on the basis of the test results, a mathematical model was developed for the maximum shear modulus.
523
Soil Mechanics Classic
Experimental and numerical investigation on circular footing subjected to incremental cyclic loads
Moghaddas Tafreshi
S. N.
^{
h
}
Tavakoli Mehrjardi
Gh.
^{
i
}
Ahmadi
M.
^{
j
}
^{
h
}K.N. Toosi University of Technology
^{
i
}K.N. Toosi University of Technology
^{
j
}K.N. Toosi University of Technology
1
12
2011
9
4
265
274
12
01
2011
23
11
2011
The results of laboratory model tests and numerical analysis on circular footings supported on sand bed under incremental
cyclic loads are presented. The incremental values of intensity of cyclic loads (loading, unloading and reloading) were applied
on the footing to evaluate the response of footing and also to obtain the value of elastic rebound of the footing corresponding
to each cycle of load. The effect of sand relative density of 42%, 62%, and 72% and different circular footing area of 25, 50,
and 100cm2 were investigated on the value of coefficient of elastic uniform compression of sand (CEUC). The results show that
the value of coefficient of elastic uniform compression of sand was increased by increasing the sand relative density while with
increase the footing area the value of coefficient of elastic uniform compression of sand was decreases. The responses of footing
and the quantitative variations of CEUC with footing area and soil relative density obtained from experimental results show a
good consistency with the obtained numerical result using “FLAC-3D”.
413
Soil Mechanics Classic
An improved solution to capillary rise of water in soils
Farshbaf Aghajani
Hamed
^{
k
}
Soroush
Abbas
^{
l
}
Tabatabaie Shourijeh
Piltan
^{
m
}
^{
k
}Amirkabir University of Technology
^{
l
}Amirkabir University of Technology
^{
m
}Amirkabir University of Technology
1
12
2011
9
4
275
281
15
03
2010
19
11
2015
Evaluating the rate and maximum height of capillary rise is of prime interest in unsaturated soil mechanics. Antecedent solutions
to this problem have dwelled mostly on determining the maximum capillary rise height, overlooking moisture and suction changes
in the capillary region. A comprehensive improved solution for the capillary rise of water in soils is presented. Salient features of
the formulation including consideration of initial soil suction (if any) prior to capillary rise, and determination of water content
variation in the capillary region are elaborately discussed. Results reveal that suction head variation within the capillary region
is non-linear, where the curvature decreases as water rises to higher elevations. The solution is verified and compared with
existing solutions, by means of two sets of experimental data available in the literature. The comparison suggests that the
improved formulation is more accurate and versatile than previous solutions for capillary rise.
374
Soil Mechanics Classic
Three dimensional bearing capacity analysis of shallow foundations using discrete element method
Majidi
A. R.
^{
n
}
Mirghasemi
A.A.
^{
o
}
Arabshahi
M.
^{
p
}
^{
n
}Mahab Ghodss Consulting Engineering Company
^{
o
}University of Tehran
^{
p
}University of Tehran
1
12
2011
9
4
282
292
19
12
2009
19
11
2015
In the current study, an effort is made to determine three dimensional bearing capacity of rectangular foundations using Discrete
Element Method. The soil mass is modeled as discrete blocks connected with Winkler springs. Different factors affect the geometry
of failure surface. Six independent angles are used to define the failure surface. By trial and error, the optimum shape of failure
surface beneath the foundation can be found. The paper includes the derivation of the governing equations for this DEM based
formulation in three dimensional state as well as parametric sensitivity analyses and comparison with other methods. Moreover,
using the current method, bearing capacity coefficients are presented for various friction angles and foundation aspect ratios.
446
Soil Mechanics Classic
Investigation of foundations behavior by implementation of a developed constitutive soil model in the ZEL method
Jahanandish
M.
^{
}
Veiskarami
M.
^{
}
Ghahramani
A.
^{
}
^{
}Shiraz University
^{
}Shiraz University
^{
}Shiraz University
1
12
2011
9
4
293
306
28
05
2010
04
12
2011
Foundations behavior is affected by soil behavior which can vary from dilative to contractive depending on the stress level,
particularly in dense frictional soils. The Zero Extension Lines (ZEL) method has been generally developed to predict the
foundations behavior. Knowledge of soil behavior enables the ZEL method to predict the general and local shear failure modes.
In this paper, a relatively simple work hardening/softening soil constitutive model is developed to represent dense frictional soils
behavior under different stress levels. This model is based on the accumulation of the plastic work during a simple direct shear
test and its relationship to stress ratio to establish the hardening law. Verifications have been made for the developed soil model.
The model is then implemented into the ZEL method to theoretically investigate the bearing capacity and load-displacement
behavior of foundations over dense frictional soils. Utilization of this model enables the ZEL method to capture different modes
of failure depending on the foundation size. A numerical study on foundations behavior was performed showing the ability of the
presented approach in capturing both failure modes.
275
Soil Mechanics Classic
Undrained triaxial shear behavior of grouted carbonate sands
Hassanlourad
M.
^{
}
Salehzadeh
H.
^{
}
Shahnazari
H.
^{
}
^{
}Imam Khomeini International University
^{
}Iran University of Science and Technology
^{
}Iran University of Science and Technology
1
12
2011
9
4
307
314
06
09
2009
19
11
2015
The effects of cementation and the physical properties of grains on the shear behavior of grouted sands are investigated in this
paper. The consolidated-undrained triaxial shear behavior of three grouted carbonate sands with different physical properties,
including particle size distribution, particle shape and void ratio, was studied. Two sands were obtained from the north shores
of the Persian Gulf, south of Iran, called Hormoz and Kish islands sands, and one sand was obtained from the south beaches
of England and called Rock beach sand. The selected sands were grouted using a chemical grout of sodium silicate and tested
after one month of curing. Test results showed that the effect of bonding on the shear behavior and strength depends on the bond
strength and confining pressure. In addition, the shear behavior, yield strength and shear strength of grouted sands under
constant conditions, including the initial relative density, bonds strength, confining pressure and loading, were affected by the
physical properties of the sands. Furthermore, the parameters of the Mohr-Coulomb shear strength failure envelope, including
the cohesion and internal friction angle of grouted sands under constant conditions, were affected by the physical properties
and structure of the soils.