Assesment of Damage of Buildings Constructed in Expansive Soil Areas of Addis Ababa
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Date
2015-11
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Addis Ababa University
Abstract
Under the action of heavy loads, greater than the swelling pressure, the soil
undergoes consolidation. The rate of consolidation depends on the applied load,
coefficient of permeability, thickness, and compressibility of the soil.
The objective of this thesis is, therefore, mainly intended to investigate the
relationship between swelling & consolidation behavior of expansive soils of Galan
Town using one-dimensional consolidation theory of Terzaghi. To attain the purpose
of this research, representative disturbed & undisturbed samples of expansive soil
were collected from different locations of Galan town & a series of swellconsolidation
tests were carried out in the laboratory.
According to the test result obtained from Index property tests, the expansive soil of
Galan Town, according to USCS is classified as Inorganic Clays soil of high
plasticity, CH, & A-7-5 according AASHTO soil classification.
The value of compression index Cc obtained from expansive soils of Galan Town,
ranges from 0.24-0.34 & the value of coefficient of consolidation Cv ranges from
0.32-0.42 m2/year, while initial dry density & initial moisture content range of 1.17-
1.37 g/cm3 & 30.6-50.1% respectively during the sample collection
In the course of this research, it has been found that swelling potential of expansive
soils decrease with increase in initial moisture content for constant dry density.
On the other had the percent swell & swelling pressure increase with increasing
initial dry density increases. Maximum swelling pressure is obtained from the
samples prepared with optimum moisture content & maximum dry density.
The value of compression index Cc of sample with high swelling potential (high
degree of disturbance) is greater as compared to samples with low swelling potential.
Increase in moisture content decreases the amount & rate of both swell and
consolidation.
Therefore, the consolidation characteristic of expansive soil is not inherent property
of the soil mass because, swelling is also additional factor that can influence
consolidation characteristics expansive soil.
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Geotechnical Engineering