The effects of water runoff and rainfall patterns over primary layers of the soil in Denizli area , related to stability of foundations and the resulting special design requirements
Adriana-Daniela Sandu , Bachelor
Student ,Faculty of Building and Civil Engineering
Ovidius
University , Constanta , Romania
[ PREVIEW ]
Within the past years , Turkey had showen a
substantial economical development, therefore ,an increase in
construction areas is demanded .
Denizli
is located in southwestern part of Anatolia and in southeast of the
Aegean Region.It
lies between 28°30’ and 29°30’ east longitude and 37°12’ and
38°12’ of north latitude. The ground water table is to be found in
general to a minimum depth of 10 m .
A
terrestrial climate may be found in the center of the area , as a
consequence of being a pathway from seaside to inland parts. The land
is open to winds coming from Aegean Sea , because of the
perpendicularity of the mountains to the sea. Winters are rainy in
general and mild in the most of the cases.
The
soils from this part of region are classified in class 7 of soils.
That means they have limitations very severe, being unable to be used
for arable culture or permanent pasture, very drastic climate, low
water-holding capacity , not too deep water level. May have also high
capablity for forests and special fruit trees , as pomegranates and
olive trees.
In the concept of active performance of stability
design of a construction , the problem of water runoff and rainfall
patterns demands an urgent evaluation of structures response at the
limit stages of every possible scenario . In this paper ,
foundations design , stablity and performance under certain carried
loads from precipitations water influence over the soil is subjected
to a closer , theoretical approach and examination as a throwback
response and its consequences thru the future .
Effects of rainfall patterns over primary layers of
the soil represent an unusual problem to be analyzed for Denizli
area, regarding the fact that the main concern for this part of
Turkey is considered to be the influence of the earthquakes and the
active faults over stabilty of the structures and not only.
Predicition of an inelastic displacement response by
leveling dissipated energy of the foundations according to the one
inputed by a combination of earthquake energy and reccuring
displacements , displacements on the horizontal and vertical
direction of the soil, obtained from the water influence and
precipitations is demanded for the stablity of the structure.
Response of a structure and its foundation in a short period range is
going from 0 to higher limit in a short time, comparing to the fact
that , in a long range , subjected to the same intensity of loads,
forces and moments, is going to be constant. The most important
parameters for evaluation of a dynamic response are shear mdulus and
the damping ratio , both factors of cyclic shear strain.
Soil-structure interaction doesn't have to be regarded
as a compact and unique connection . By defining the limits of each
member ,both structure and soil to a lower level , the strength of
the of the dynamic system will go to an appropriate safety form .
Taking this into account , computation of all parameters such as
bearing capacity , settlement , appropiate reinforcement , overburden
pressure , acceleration and velocity of the displacements will be
regarded not reaching safety limits.
Each substructure has a specific dynamic response due
to external actions . Choosing the most suitable type of foundation
as a result of a cumulative factors is the first most important thing
. As it is mentioned before , ground water table is an important
element for this . It is very important that GWT should be maintained
under the footing level , in order to prevent a future uplift or
flotation , that it will be added to a doubtful safety of the
footing.
The presence or the lack of water in the soil is vital
for computation of soil strength and future settlement. Water
exceeding in the soil is one of the most dangerous factors regrding
the safety of a permanent settlement of a construction or a future
collapse or ,in the best case only the occurence of a cracking.
Obermeyer claimed the fact that for a saturated soil
mass , the stress release during excavation can result in
significantly more negative pore pressure in the underlying soils .
Thus , water can flow into the soil beneath the subjected area and
cause swelling. If the water will subject the pores to a pressure
enough to carry the load , it will result a hold apart of the
particles , resulting an alomost quicksands behavior .The initial
part of the soil which has accumulated pressure will succesively move
the points of concentrations, once they will be liquefied. Chu had
noticed an important factor of influnce : fatigue of swelling .
Considering it , if the drying and wetting cycles are going to be
repeated , the swelling during the first cycle would going to be
appreciably higher than in subsequent cycles.
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| Rainfall Distribution (1971-2000) |
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