1 Research on geotechnical earthquake

RICARDO PALMA UNIVERSITY
FACULTY OF ENGINEERING
CIVIL ENGINEERING
RESEARCH INSTITITUTE
RESEARCH ON
GEOTECHNICAL
EARTHQUAKE IN THE
HUMAN SETTLEMENT
OF LIMA-PERU
RESEARCH ON
GEOTECHNICAL
EARTHQUAKE IN
THE “HUMAN
SETTLEMENTS”
OF LIMA-PERU
ADVISERS:
Dr. ARNALDO CARRILLO GIL
Ing. OSCAR DONAYRE CORDOVA
1. INTRODUCTION
With field explorations and the
obtained information from surveys
made by the students, many places
were
identified
where
common
construction of “pircas” were used. A
model was developed in order to
analyze their static and seismic
conditions, considering the earthquake
magnitude according to the site
seismic recurrence and building
characteristics as well as their risk and
vulnerability due to more common
disasters.
Geotechnical model
Typical foundations on “pircas”
A typical case of slope failure was
considered in order to determine
through back analysis and test in situ,
the resistance average parameters to
shear strength. Data was evaluated on
laboratory, in a real scale prototype
with the geotechnical site conditions. In
addition, geological characteristics of
the site were also considered.
In situ model of “pircas” foundation
2. GEOTHECNICAL CONDITIONS
In the field were made penetration
tests and exploration pits and then
tested in the laboratory each soil
sample extracted.
From a statistical standpoint, the
survey of a sample of the population of
the area to evaluate the situation and /
or condition of building their homes
and the behavior of people in an
earthquake
It
took
the
dimensions
and
characteristics of the house collapsed
as shown in the following figure.
Field Works
3. METHODS
DESIGN
FOR GEOTHECNICAL
3.1 Slide 5.0
Slide 5.0 is a 2D program Slope
stability to evaluate the stability of
circular or no circular failure surfaces
of soil or rock slopes. You can create
complex models, modeling external
loads, groundwater and supports a
variety of ways.
3.2 Slope/W
El software Slope/W is a product tha
use the balance limit to calculate the
security factor on earth and rock
slopes. Slope/W has an application for
the analysis and geothecnical, civil
design,
and
projects
of
mine
engineering.
Measurements of the collapse
5. CALCULATION OF THE
PARAMETERS OF SHEAR STRENGTH
OF SOILS
In this study the calculation of these
parameters was made by the Method
of retro Analysis because there was no
such information at the moment of the
collapse.
3.3 MacStar 2000
The program MacStar 2000 has been
developed to verify the stability of
reinforced soil, which are structures
that provide stability on a slope using
units of reinforcements that can absorb
tensile stress.
4. MODELING OF THE COLLAPSE
AREA
Screen of Slide 5.0 showing one of the
safety factors
6. SEISMIC ACCELERATION
COEFFICIENTS
8. CONCLUSSIONS AND
RECOMMENDATIONS
For the particular case of the software
you need to have additional data
seismic
acceleration
coefficients,
horizontal and vertical, especially for
the analysis of the model under
dynamic condition.
1.
2.
Seismic acceleration coefficients
Horizontal
0.15
Vertical
0.072
3.
4.
7. DISCUSSION RESULTS
Results show safety factors that are
lower than 1, and significantly lower in
case of an earthquake of shallow
acceleration of 0.30g and magnitude of
7.5Mw, values which point out that it is
not necessary an earthquake to cause
slides on the foundation. Because of
these results, it is essential to check
for practical and economical solutions
in order to avoid material and human
losses (Figure 8). The progress of
these studies allows us to establish the
construction
process
in
walls,
platforms, and foundations.
Factor of Safety
5.
6.
The failure rate of housing
construction in these settlements is
really alarming because of the lack
of supervision or technical criteria.
The vulnerability of households in
most human settlements because
they are located on hill slopes, with
a foundation inappropriate, a very
steep slope and with materials that
do not guarantee static and
dynamic stability of the building.
This vulnerability is directly related
to the safety factors calculated by
different methods that have been
presented,
the
same
as
determining whether an area is
stable or not.
“Human Settlements” those are
most vulnerable due to the high
recurrence of the use of stone
walls.
The survey techniques found in
each field work demonstrate the
absence of information to the
residents of these sectors has on
the direct or indirect damages that
result in a collapse.
This paper has complied with its
commitment to demonstrate the
vulnerability of this type of existing
foundations type Pirca.
REFERENCES
Condition
Factor of
Safety
Method
Static
Seismic
Slide 5.0
0.913
0.755
Slope/W
0.847
0.712
McStar
2000
0.911
0.701
– Braja M. Das, “Principles of
Foundation Engineering”, Fourth
Edition.
– Carrillo Gil, Arnaldo “Geotecnia de
los Suelos Peruanos” Instituto
Peruano de Ingeniería Geotécnica y
Geoambiental, Lima, Perú.
– Carrillo Gil, Arnaldo, “Peligro
sísmico en los Barrios Marginales
del Sur”, Conferencia Instituto
Peruano de Ingeniería Geotécnica y
–
–
–
–
–
–
Geoambiental, CIP, CDL, Lima,
Perú.
Carrillo Gil, Arnaldo “Education and
Practice: The Peruvian experience”
17th International Conference on
Soil Mechanics and Geotechnical
Engineering, Alexandria, Egypt.
Donayre, Oscar, “Evaluación del
Comportamiento de los Suelos
Granulares Finos del Sur de Lima
Metropolitana”, Tesis de Grado
Universidad Ricardo Palma.
Hoek, Evert, “Hoek – Brown Failure
Criterion”, Edición 2002, pag. 1-7.
Juárez Badillo, Rico Rodríguez,
“Mecánica de Suelos”, Tomo 1
Editorial Limusa S.A.
Kramer, Steven L., “Geothecnical
Earthquake Engineering”, University
of Washington, Prentice Hall, New
Jersey, Cap. 11, pags. 466 – 505.
RocLab, User’s Guide, pags. 1 – 27.
– Sandoval,
Israel,
“Evaluación
Geotécnica y Sísmica de los
Asentamientos Humanos del Norte
de Lima Metropolitana”, Tesis de
Grado Universidad Ricardo Palma.
– Slide 5.0, “2D Limit Equilibrium
Slope Stability for Soil and Rock
Slopes”, Manual de Usuario, Cap. 1
y 2, Rocscience Inc.Slope/W, User’s
Guide.
– Torres, César, “Valoración del
Riesgo en Deslizamientos”, Tesis
de Grado Universidad Ricardo
Palma..
– Whitman, Robert V., “Dynamic
Behavior of Soils and its Application
to Civil Engineering Projects”, Sixth
Panamerican Conference on Soil
Mechanics
and
Foundation
Engineering, Lima – Perú.
– Whitman, Robert V., “Limiting Cases
for Distribution of Lateral Stress,
Sixth Panamerican Conference on
Soil Mechanics and Foundation
Engineering, Lima – Perú.