ABSTRACT
Seven
empirical models for calculating hydraulic conductivities in soils based on
grain-size distribution were investigated in this study. The results were
compared with hydraulic conductivity of soils computed using the constant head
permeability test. Three samples were collected from three trial pits in
different locations along the bank of the stream located downstream of National
Root Crops Research Institute's earth dam, Umudike, Abia State Nigeria. The
samples were subjected to sieve analysis and the constant head permeability
tests using standard methods. Hydraulic conductivities in soils computed from
the empirical formulae were each compared with hydraulic conductivity
calculated using the constant head formula. Results showed that mean hydraulic
conductivities for constant head, Hazen, Breyer, Kozeny-Carman, USBR, Kozeny,
Terzaghi and Slitcher models were 18.16 m/d, 35.52 m/d, 34.80 m/d, 30.50 m/d,
25.86 m/d, 19.08 m/d, 15.66 m/d and 10.86 m/d respectively. ANOVA results for
pairwise comparison indicated that Kozeny formula gave the best performance
with a p-value of 0.78 at 0.05 critical value. This was followed by Terzaghi,
USBR and Slitcher with p-values of 0.44, 0.11 and 0.059 respectively, while the
Kozeny-Carman, Hazen and Breyer performed poorly with p-values of 0.03, 0.008
and 0.007 respectively. Confirmatory test carried out using the Dunnett
simultaneous software package for level mean - control mean, produced an
adjusted p-value which was highest at 1.000 for Kozeny model. In all the tests,
Kozeny, Terzaghi, Slitcher and USBR performed well with p-values 1.000, 0.923,
0.117, and 0.092 above the critical value of 0.05, while the Breyer, Hazen, and
Kozeny-Carman performed poorly with p-values 0.000, 0.000 and 0.004 below the
same critical value. They result further showed that Slitcher model is the best
for estimation of hydraulic conductivity with root mean square error (RMSE) of
6.78, mean absolute error (MAE) of 5.73, relative error (RE) of 26.71 and
deviation time (DT) of 1.46, From the results of the adjusted p-value, Kozeny
and Terzaghi were the best at 1.0 and 0.923 respectively while Breyer and Hazen
were the worst at 0. There exists high level of inconsistencies in the findings
from different researchers and therefore further researches are
recommended.
EBOH, S (2023). Investigation of empirical models for Hydraulic conductivity from Grain-size distribution. Mouau.afribary.org: Retrieved Dec 25, 2024, from https://repository.mouau.edu.ng/work/view/investigation-of-empirical-models-for-hydraulic-conductivity-from-grain-size-distribution-7-2
SOLOMON, EBOH. "Investigation of empirical models for Hydraulic conductivity from Grain-size distribution" Mouau.afribary.org. Mouau.afribary.org, 15 May. 2023, https://repository.mouau.edu.ng/work/view/investigation-of-empirical-models-for-hydraulic-conductivity-from-grain-size-distribution-7-2. Accessed 25 Dec. 2024.
SOLOMON, EBOH. "Investigation of empirical models for Hydraulic conductivity from Grain-size distribution". Mouau.afribary.org, Mouau.afribary.org, 15 May. 2023. Web. 25 Dec. 2024. < https://repository.mouau.edu.ng/work/view/investigation-of-empirical-models-for-hydraulic-conductivity-from-grain-size-distribution-7-2 >.
SOLOMON, EBOH. "Investigation of empirical models for Hydraulic conductivity from Grain-size distribution" Mouau.afribary.org (2023). Accessed 25 Dec. 2024. https://repository.mouau.edu.ng/work/view/investigation-of-empirical-models-for-hydraulic-conductivity-from-grain-size-distribution-7-2