2655
Technical Committee 212 /
Comité technique 212
expanding high density geopolymer to a geotextile tube. It can
be used as end bearing and/or friction piles with the dependence
of soil conditions. While injected, the pillars volume expands
fast, which will cause the surrounding soils displaced and
compacted. Totally there have been over 500 projects so far.
Some load tests and material tests are presented in this paper.
Poulos et al. performed pile load test for verifying the
foundation design of a tower in South Korea. Four pile load test
were performed on vertically loaded piles using the Osterberg
cell method, while one was performed on a laterally loaded pile
which were jacked against each other. Authors also carried out
finite element analyses using the computer program PLAXIS
for determining the effects of pile shape and quality of concrete
which were used while conducting the pile load test. It was
found that while pile load capacities were underestimated at
over - break levels; they were overestimated during shaking,
due to non – consideration of diameter of the pile during the
analyses. It was concluded by the authors that non – uniformity
of pile section and quality of concrete should be considered for
accurate interpretation of pile load test data.
Powell and Skinner presented the data of tested piles on
London clay which was located at Chattenden, northern Kent
and was underlain by high plasticity London Clay to a depth
of at least 44m. This paper presents testing of piles which is
now in use onto the soil, pile tested at an age of up to 5
months, but mostly 2.5-3.5 months, by static incremental
maintained load testing (ML). The Topic, RuFUS and
RaPPER pile tests were undertaken using a combination of
BRE load frames and a remotely operated hydraulic loading
and control system. Through testing α (empirical factor for
shaft resistance) was found out for different types of piles and
reported and α will be incorporated in the design of pile
capacity.
Puech and Benzaria presented an experimental study on
the behaviour of piles under axial static load. Three mode of
pile installation were considered: driving, boring, and
screwing. Piles tested were instrumented with removable
extensiometers and installed in the overconsolidated Franders
clay. The results showed very high skin friction mobilized for
driven pile (>150 kPa); that of bored pile and screwed pile are
lower, 40 kPa and 60 kPa, respectively. The experimental
results were finally compared to the prediction methods
developed by Imperial College or recommended by French
codes.
Ramadan et al. developed a model in PLAXIS 3D to study
the importance of piled supporting system to the excavation
adjacent to existing buildings in soft to medium clay. For the
present study authors considered the excavation area as 10 x
10m and the foundation of adjacent building as three strip
footings of length 10m and width 2m with 100kN/m
2
stress on
the foundation level. From the analysis authors concluded that;
1. For stability number N
c
= 4 the unsupported excavation was
fail due to stress of the adjacent building.
2. Continuous pile wall support wall was decreased the lateral
soil displacement between the foundation level of the adjacent
building and the bottom of the excavation.
Ray and Wolf outlined the past history and present
implementation of foundation design when subjected to seismic
loading in Hungary as per Eurocode 8. Authors also used SAP
2000 finite element software for analyzing the influence of
different support conditions on the bearing stresses of a
superstructure on a typical reinforced concrete building. The
building periods of the structure were computed using the
Eurocode 8 formulae and modal analyses which considered
fixed base and spring base supports, giving building periods of
0.85sec, 0.69sec and 0.79sec respectively. It was observed that
foundations having spring base conditions reduced the bending
moments near the base by 30%, with the reduction being less at
the higher portion of the column. Moreover a decrease in
fundamental period owing to different support conditions,
resulted in an increase in magnitude of spectral ordinate and
bending moment.
Rinaldi and Viguera performed pseudo-static load tests for
evaluating the bearing capacity of large diameter piles. Authors
showed that moderate loads, weighing between 10 to 20 tons,
when dropped from a height of 10cm to 120cm, resulted in full
mobilization of ultimate pile capacity. The loading generated a
time controlled load which depended on the size and height of
fall of the load, geometry and elastic properties of the
elastomeric cushion which were included between the mass and
top of the pile. It was concluded by the authors that pseudo-
static methods allowed application of load increments in steps,
repeatability of each loading step and simpler test setup, when
compared to Statnamic tests.
Sakr and Nasr investigated the effects of inclined load on
axial pile displacement and lateral pile response for single pile
embedded in the level ground and near ground slope by
conducting several experiments. Authors compared the results
of single pile founded in the level ground with that in near
ground slope and concluded that;
1. The ultimate axial and lateral load capacities of pile were
decreased with increase in inclination of load with vertical.
2. The ultimate lateral load capacity of pile founded in dense
sand subjected to inclined loads increased significantly with
increase in slenderness ratio.
3. The lateral load capacity of pile was increased with increase
in distance between pile head and slope crest for different
densities of sand.
Salgado et al. proposed semi-analytical methods to calculate
the response of laterally loaded piles with general-shape cross
sections embedded in multilayered elastic soil. The method
produces results with accuracy comparable with that of a 3D FE
analysis but requires much less computational time. Analytical
solutions for laterally loaded piles with rectangular and circular
cross sections embedded in multilayered elastic media are
obtained. The solutions for pile deflection, slope of the
deflected curve, bending moment and shear force, are obtained
iteratively and it depends on the rate at which the displacements
in soil medium decreases with increasing distance from the pile.
Shulyatiev et al. described a new field test technique
developed for the analysis of single pile and pile groups in
Moscow International Business Center (MIBC) “Moskva-
CITY” is a complex of 19 sky-scraper buildings. Authors were
analyzed single pile and pile groups of length range 20 – 30m,
diameter range 1.2 – 1.5m and spacing range 3 – 5m. Authors
determined separately side resistance and tip resistance in the
site by using that developed test technique and verified with
analytical model developed in PAXIS 2D 8.2 software for
single pile test data.
Silva et al. (a) proposed a method to mitigate risk in
geotechnical constructions by using borings and pile load tests
that enable the elaboration of bi and three-dimensional models,
which gives assure that the correct analysis and evaluation of
the associated risks to design and to the construction execution
should be one of the targets of a Geotechnical Engineering.
From the results authors concluded that the process of post-
evaluation of the models developed in computer software
requires geological/geotechnical experience of the region and
knowledge of limitations and potential advantages of the
computer software as the quantity of input attributes, working
grid limit, interpolating devices and their limitations.
Silva et al. (b) proposed the use of SCCAP methodology to
control the execution of CFA types foundation works which
proposes formulations, routines and criteria for pile acceptance.
To ensure quality and the design assumptions, the SCCAP
routines introduces to the execution monitoring software for
CFA piles the excavation quality control in real time and assure
the execution piling process conditions for the piles to achieve
the planned bearing capacity. Through SCCAP quality in the
excavation can be assured whose results rely upon the bearing
capacity and deformability through the decrease of the
