Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : collapsibility


Improvement of Sabkha Soil by Using Geomesh and Addition of Polycoa

Hassan Obaid Abbas

Engineering and Technology Journal, 2012, Volume 30, Issue 4, Pages 568-576

Sabkha soil is a rich soil with salt deposited which result from evaporation of
water, it is one of the many types of collapsible soils and in turn is one of the many
types of problematic soils. This soil totally has good engineering properties when dry
,i.e ,moderately bearing capacity with low settlement. But once is wetted it loses its
entire structure (collapse) and undergoes very large instantaneous settlement. A
laboratory model test consists of a cylindrical steel container of 270mm diameter and
300mm height, the soil is brought from Al-Khalis discrete. The density of soil is
controlled by placing the required weight inside the container of known volume, to
the required height. A square footing 40mmx40mm makes from steel is used. The
stress is applied from a fixed loading system designed especially for model tests.
In this study two types of improvement are used , the first improvement consists
of fine geomesh under footing at different depth (0.5B,B,2B),the second
improvement is the addition of polycoat with different concentration to surface of soil
.The first method do not give good results of improvement but the second method
gives good improvement which reduces the collapsibility to 62% at stress level of
50kPa.

Effect of Adding Fine Gravel and Cement on Settlement of Sabkha Soil

Hassan Obaid Abbas

Engineering and Technology Journal, 2012, Volume 30, Issue 1, Pages 87-97

Sabkha soil is one of the many types of collapsible soils and in turn is on of the
many types of problematic soils. This soil is totally having good engineering
properties when dry ,i.e ,moderately bearing capacity with low settlement .But once
are wetted they loose their entire structure (collapse) and undergo very large
instantaneous settlement .A laboratory model test consists of a cylindrical steel
container of 270mm diameter and 300mm height, the soil is brought from Al-Khalis
discrete .The density of soil is controlled by placing the required weight inside the
container of known volume, to the required height .A square footing 60x60mm makes
from steel is used .The stress is applied from a fixed loading system designed
especially for model tests .In this study two types of treatment carried out ,the first
treatment is added fine gravel only with percentages (2%,4.5%,6%) to soil which is
not give good improvement .The second type of improvement is added 3% of cement
with fine gravel (4.5%,6%) percentages which give good improvement, reduced the
collapsibility to 84% .Also, when adding 3% of cement with 4.5% fine gravel to soil
,give good improvement, reduced the collapsibility to 90% .

Improvement of Gypseous Soil by Clinker Additive

Mohammed A. Mahmoud Al-Neami

Engineering and Technology Journal, 2010, Volume 28, Issue 19, Pages 5822-5832

In this paper, mechanical properties were studied for gypseous soil
brought up from Al-Axandria region, Babylon Governorate. Gypsum
content is equal to (40%). Many tests were employed on disturbed and
undisturbed samples collected at depth (1-1.5) m.
Clinker material used in cement was chosen as additive to study its
effect on improvement of gypseous soil by using three crushed percentages
(2, 4, & 6) %.
The results marked that (4) % clinker decreases the collapsibility
sharply; more than 73 % of improvement in collapse potential has been
achieved at this percent of clinker. Also, compressibility decreases with
increase of clinker percentage. The compression index decreased from 0.17
to 0.1 (29 – 41% reduction with increases of clinker).
The shear strength parameters of the treated soil determined by
direct shear test are more those than for natural soils due to increase in the
cohesion and decrease in angle of internal friction.