Abstract:
Expansive soils have a special mineralogical characteristic which leads to swelling
when exposed to moisture change. This behavior is due to the presence of
considerable amount of montmorillonite clay mineral. Lightly loaded engineering
structures such as pavements, single story buildings, railways and walkways may
experience severe damages when they are constructed on such soils. Quantifying the
swelling pressure for expansive soils caused by their expansion are essential in
geotechnical engineering. Different researchers have developed an empirical relation
for the estimation of swelling pressure from index properties of expansive soils for
their locality. The formation and development of soil structure has very erratic nature
and the swell pressure is dependent on the stress conditions, environmental factors
and soil characteristics which vary from place to place, therefore equations
developed for soils in one place may not work at all if tested on soils of other place of
the same region. Hence specific models have to be developed for specific areas in
order to give fair evaluations. As aresult new model is going to be determined for
soils founed in Bahir Dar. To this regard, a series of laboratory tests were conducted
on representative expansive soil samples. Laboratory tests such as free swell, specific
gravity, particle size distribution, atterberg limits, natural moisture content, dry
density and swelling pressure was conducted. Using index properties of soils as
independent variable and swelling pressure as dependant variable, both linear and
multiple linear regression analysis was undertaken by employing SPSS 2020
softwere. Accordingly the results of the statistical analysis show that good correlation
does exist between index properties and swelling pressure of expansive soils. Using
the measured swelling pressure and predicted swelling pressure, replacement depth to
counterforce the swelling was calculated.