HİDROLİK KONDAKTİVİTE TAYİN METOTLARININ ERZURUM OVASI DRENAJ PROBLEM SAHA TOPRAKLARINDA KULLANILABİLME İMKANLARI ÜZERİNDE BİR ARAŞTIRMA

Year 1972, Volume: 3 Issue: 3, - , 11.12.2010

Ersan Gemalmaz

Abstract

ÖZET
Erzurum ovasının Yeşilyayla, Muratgeldi, Yolgeçit, Güzelova,
çayırtepe, Soğucak köyleri arazilerindeki drenaj problemlerinin
çözümü için toprakların hidrolik kondakitiviteleriııi tayin etmede
mevcut hidrolik kondaktivite tayin _metotlarının kullanılabilme imkanlarım
tespit etmek amacıyle yapılmış olan bu araştırmada, araştırma
sahasında toprakların hidrolik kondaktiviteleriııin tayini için
piezometre, well point, bozulmamış numune, hava girışli permeametre
VSDA - ses tarafından önerilen tekstür+strüktür kore- , i
lasyonu, Hom tarafindan önerilen ortalama tane çapı - permeabilite
korelasyonu metotlarının elveirışli olacakları sonul!Una varılmıştır.

ARESEARCH ON THE PRACTIBILITIES OF HYDRAULIC CONDUCTIVITY DETERMINATION METHODS IN THE SOILS OF
THE DRAINAGE PROBLEM AREAS OF ERZURUM VALLEY

One of the most influeneing factors
related drainage planning is
hydraulic conductivity.
Success of a drainage project depends
on the determinatian of hydrauJic
conductivity which will be the measure
of the rea! hydr~ulic conductivity of the
soils with which the project is dealing.
Even though selection of the method
for the deternlination of the hydraulic
conductivity among those developed
methods to satisfy our needs best
depends on the conditions of the soils
in the drainage problem area; it also
depends on the technical personal and
the availability of necessary equipments.
Taking into consideration these
peculiarities mentioned in the above
paragraph, this reseaıch has been done
to find the most suitable methods for
determining the soil permeabilities in
the lands of Yeşilyayla, Muratgeldi,
Yolgeçit, Güzelova, Kösemehmet, Çayırtepe
and Soğucak viııages which are
heavy drainage problem areas of Erzurum
valIey.
Twenty-five places having dissimilar
profile characteristics were chosen
for experiments and soil permeabilities
were determined for different depths
in these places below the water table
by piezometer method. Undisturbed soil
cores were taken from the soil 'layer
above the water table for the same
places to determine soil permeability
in the laboratory. Disturbed samples
to represent the soil layers as perfectly
as possible were alsa taken fıom these
places, which a piezometer was driven
and undisturbed soİI cores picked,
an,d the water used in piezometer
tests wcre obtained to analyze later
in the laboratory.
Structuml and textural anaIyses
were made and va]ues of "soiI pH
measured İn water" were deteı:mined,
chemical analyses were made to determine
organic matter and carbonate
in the soil samples; Na+, ca++ +
Mg++, pH and electricaI conductivities
of the water samples were measured
in the laboratory.
Undisturbed soiI samples wete
saturated under vacuum and then permeabilities
were measured by using
'constant or falIing head permeameters,
however permeability values of disturbed
soiI samples were determined by
using constant head penncameters.
Laboratory results indicated that
soils have textures changing from sandy
lo!im to elay and medium-high-very
high organic matter, however the carbonate
content of samples vaıied within
large limits.
Surveyed soiI strata have granuIarı
black, sirıgIe and massiye soil structures.
A1though usually massiye structure
is observed in lower and granular
structure in upper layers, Lhere
are some exceptions.
Chemical analyses of the water
samples obtained from the places having
extreme drainage pı oblem indicated
saline and saline-alkali conditions.
The results of the soil permeabi1ity
tests show that research area soils consist
of layers having very different hydraulic
conductivities and in addition soil
surveys indicate big differences in the
thickness and depth of the soillayers.
All of the determined soil properties
clearly point out the heterogeneous
character of research area soils. The
(ollowing conclusions are reached,
for the potentilal use of the present
hydraulic conductivity determination
methods in the research area soils,
in the light of the knowledge gained
through field, laboratory and offiçe
work:
Piezo~eter and Pomana wel1-point
methods which are used for measuring
the hydraulie conductivity in situ
have the possibİ!ity of potential use
in layered research area soils. Use of
auger-hole methods could faıse results
because soils are layered and the sensitiye
deliniation of the soil strata with
auger is very difricult.
Tube method is not advisable far
reseaı ch area soijs because of high
water table requirements and survey
difficiulties when water table is high;
and also conduetivity measnremenb
with this method is limited to relatively
shallow ,,depths.
Childs'two-well, Kirkha:qı's tourweII
and well discharging methods require
same conditions that are ditricult to
obtain or to find in the research area;
therefore use of these methods are very
limited.
Air entry permeameter method
for the measurement of penneability
ahove water table was found advantageous
to determine hydraulic conductivity
of the upper soil strata in the research
area. The other methods used to measure
permeability above a water table require
excessive' amount .of material
and time. Hence they were not found
praetical to use. Determinatio~ of soil
permeability with undisturbed soil co"
res need more repIicates than the other
advised methods because of the size
and heterogeruty of this area;therefore
it is not suggested as a proper method
for the drainage surveys.
Results of the soil permeability
tests conducted on djsturbed soil samples
did not give any carrelation with
results obtained from undisturbed cores
and measurements in place, therefore
use' of disturbed soil samples for
deterınining hydraulic conductivity is
not suitable for research area soils.
There are some advisable methods
as mentioned above for direct measurement
of permeability in the research
area, however exceptionally heterogeneous
character of the soils and the
size of the drainage problem area whi-ch
hydraulic conductivity measurements
have to be conducted on is LO 000
hectares, therefore use of these methods
will require too much time and effoıt.
Those methods requiring less time,
in other words indirect permea bjlity
determinatian; simp1e texture-permeability
correlation did not seem appropriate
to use because soil structure
has more influenee than soil texture
on the permeability of the research
area soils. USDA-SCS proposed textur+
estructurecorrela tİon method may
be used with great confidenee in this
area.
In order to employ the method
proposed by Ham which uses the mean
61
parcticle size estimated from texstural
analysis, some soil texture-permeability
curves to represent .the local conditions
much better ôhould be obtained for
these parts that the reseaıch area should
alr~ady have been- divided into, considering
siınilar soil properties.
A~ a. consequence, hydraulic conductivities
could be determined by
in situ measurements to plandraİnage
faciIitief> for sma1J areas; generalization of
these results obtained from a fewactual
measurement (no matter how carefuUy
this permeability methods chosen for
Iocal conditions and applied with great
care) for val1ey soil&, however, could
cost to unneeesessary investment or
failure draİnage facilities which wiU
cost a lot of spending.

Keywords

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