1918
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
horizontal displacements, in the order of 8 mm, compatible with
the 3D FE analysis.
I. Gutjahr et al.
discuss comparisons between subgrade
reaction calculations, FE analysis using 2 different softwares
and monitoring results of an anchored retaining structure of the
Vieux Blanc-Mesnil Basin, in France.
V.A.Ilyichev and Y.A. Gotman
present a method to optimize
diaphragm wall displacements in deep excavations, by means of
using soil cement mix in the active and passive parts of the soil
massif. The dimensions and stiffness of the soil cement mix can
be estimated using the proposed computational method. FE
calculations were used to calibrate the proposed calculation
method and good agreement was obtained.
Y. S. Jang et al.
discuss two case histories from Korea of
deep excavations supported by diaphragm walls. Excavations
depths of 1 case is 20 m and of the other, 31 m. The retaining
walls are concrete diaphragm walls, steel profiles and timber,
and steel profiles and shotcrete. Horizontally, the walls are
supported by anchors, in one case, and by steel struts, in the
other case. Horizontal movements of 30 to almost 100 mm were
measured. Forces in anchors and struts were also measured and
compared to numerical simulations.
S. Jessee and K. Rollins
present model tests to evaluate the
passive pressure on skewed bridge abutments. The performed
tests showed that a significant reduction was measured, as the
skew angle increases. These results were compatible with
numerical simulations and a simple correction factor is
proposed.
M. Long et al.
present a number of case histories of
excavations in glacial tills of Ireland. 12 cases are presented,
where horizontal displacements were measured. The
displacements were, in most of the cases, less than 0,1% H. The
conclusion of the authors are that design has been conservative
and more realistic design methods and construction methods can
lead to more economic design.
D. Loukidis and R. Salgado
discuss the results of numerical
simulations of earth pressure on walls supporting granular soils.
The simulations, using Ottawa and Toyoura sands, with varying
relative densities, showed that a minimum active pressure is
obtained at 0,5% H displacement. But with higher
displacements, in the order of 10% H, critical state inside the
soil mass is mobilized. An equation is proposed to estimate the
variation of the earth pressure coefficient as a function of the
wall crest displacement.
R. Lüftenegger et al.
present case histories of non
conventional retaining structures. The structures were conceived
based on the necessity to avoid the installation under
neighboring buildings. 3D FE analyses were used to understand
behavior. Good adherence between prediction and monitoring
was not obtained, and for this reason the use of the
observational method is recommended.
T. Maeda et al.
discuss the use of inclined braceless retaining
structures in sandy soil. Instead of using a vertical face,
inclining it slightly, 10
o
, allowed the excavation of an almost 10
m deep excavation without any bracing or anchor. An analytical
design method was developed and verified by centrifuge tests.
Monitoring results from the site showed that the design method
lead to results on the safe side.
S. Nakajima et al.
present a methodology to inspect exiting
retaining structures. The methodology includes percussion tests
and vibration tests, where the natural frequency of the structures
is measured to evaluate its condition.
C.Y. Ou et al.
discuss the mechanism of settlement influence
zone due to deep excavation in soft clay. The USC model is
used for parametric analyses a method for predicting the
settlements is proposed.
J. Philipsen
discusses the case history of a braced
excavation, built under difficult conditions, in Copenhagen. The
excavation was built in quaternary clays and sands, overlaying
limestone.
A. Pinto et al.
present a case history of an anchored
excavation in Lisbon. The excavation was 13 m deep and
supported by vertical steel profiles associated to a CSM wall
and anchors. The geotechnical profile includes superficial fill,
medium sands and sandstones, and GWT 5 m below the surface.
The excavation was monitored through inclinometers, with
maximum horizontal displacements close to the surface of
around 40 mm.
Another paper by
A. Pinto et al.
present the case history of
excavations for the Leixões Terminal in Portugal. 2 different
solutions are presented: CSM panels with steel profiles and
CSM panels with micropiles. The excavation is around 6,5 m
deep and the geotechnical profile includes hydraulic fill placed
on weathered schist. CSM UCS minimum measured values
were of 4 MPa.
H. Popa et al.
discuss a case history from Bucharest. 16 m
had to be excavated to accommodate a 4 to 6 m deep basement
mat and 2 basements. The subsoil profile included interbedded
layers of medium to compact sands and medium to stiff clays,
with groundwater level 2 to 3 m above the excavation bottom.
An anchored diaphragm wall was designed, built and
monitored, with maximum horizontal displacements of less than
10 mm.
C. di Prisco and F. Pisanò
, present a new anchor type. FE
analyses are used to evaluate the pull out behavior of the
anchor. Based on the FE analyses, an analytical method is also
developed and presented.
N. Sanvitale et al.
discuss the role of the facing on the
behaviour of soil-nailed slopes under surcharge loading, using
small physical models in sand. Flexional and axial stiffness
influence the performance of the soil nailing system.
T. Tanaka et al.
present results of physical and numerical
models, where 3D seepage effects influence stability. Uniform
sand are used for the evaluations and results show that the 3D
conditions differs from those of typical 2D conditions.
Correction factors from an axisymmetric simulation to no
axisymmetric conditions are also presented.
P. Turček et al.
discuss case histories of deep excavations in
Bratislava. Local subsoil includes superficial quaternary
sediments, mainly gravel and sand, overlaying neogene marine
sediments, mainly stiff clays. Groundwater is normally at
shallow depth and its control is one of the main challenges for
successful construction.
M J Turner and N A Smith
present a case history of the
stabilization of a gravity quay wall in the UK. The 17 m high
wall, originally built at the end of the 19
th
century, suffered
stability problems since the mid 1980s, with horizontal
displacements of around 400 mm. Evaluations showed that the
difference between the high tidal variations, more than 6 m, and
the groundwater level behind the wall, were leading to
increasing horizontal displacements. Stabilization measures
included groundwater lowering and installation of anchors.
L. Vollmert et al.
discuss results of large scale in situ tests, as
well as long term monitoring results of a reinforced earth
structure. For the monitored cases, with full height panel walls
as facing, the actual lateral stress measured is significantly
lower than FE calculations or classic earth pressure theory,
showing that current design methods are on the safe side and,
possibly, a correction factor can be introduced to EBGEO
design methodology.
G. Vukotić et al.
present results of anchor bond
measurements in different soils and anchor length. The
influence of the fixed anchor lengths is evaluated, showing that
longer anchors are less efficient than shorter anchors. A
proposition or design methodology is presented, including
possible use of single bore multiple anchors – “SBMA”.
L. Warren et al.
discuss the use of drystone retaining walls,
including model tests performed in the UK. Different types of
walls, based on their construction methods, horizontal, vertical
and random, are discussed. The type of wall is presented as a
