Abstract

Sand or stone columns are considered one of the efficient methods of
improving soft clayey soils. They are cheap, easy to use, and results in
increasing the bearing capacity of the soil and decreasing its compressibility.
In this research, a series of laboratory tests were performed using small scale
columns (Dia. = 38 mm, Depth = 180 mm) inserted in a soft clay
layer which was prepared inside steel containers. Different amounts of lime
and / or cement were used to stabilize the stone columns to increase its
efficiency. Loading tests were performed on each column in order to
determine its max. bearing capacity, the efficiency of each additive was
determined by comparing the results obtained of treated to untreated
columns (qt / qu). The results were (2.7) for soils treated with crushed stone
only, and (4, 5) for soils treated with crushed stone stabilized with (5%) and
(10%) lime respectively. The results also showed (3.5, 4) for soils treated
with crushed stone stabilized with (5%) and (10%) cement respectively. The
results of stabilizing stone columns with lime and cement showed that
(qt / qu) were (3.3, 3.7) for soils treated with crushed stone stabilized with
(2.5% lime + 2.5% cement) and (5% lime + 5% cement) respectively.