EFFECT OF DEEP SOIL MIXING TO INCREASING BEARING CAPACITY ON PEAT SOIL

Abstract

The peat soils have high compressibility properties and low bearing capacity; therefore, the
settlement in peat soils is very significant. The ground improvement, such as deep stabilization needs to be
carried out to increase the bearing capacity of the peat soil. The deep stabilization or deep soil mixing (DSM)
is a method of soil improvement by the soil column reagent mixed with cement and other pozzolanic materials.
This study used the following ingredients: added clay + 12% calcium carbide residue (CCR) and clay + 8%
rice husk ash (RHA), which are expected to increase soil carrying capacity because of the properties of silica
and lime possessed by pozolan materials that can bind soil particles. The variations in diameter and the number
of DSM column test piece are as follows: 4 and 16 column variations with a diameter of 3.75 cm and 1 column
with a diameter of 15 cm. The soil mixing column is compacted in a pipe and the concrete cylinder formwork
is then pressed for 4 days. The test results showed the increased soil bearing capacity on peat using the DSM.
The DSM column (clay + CCR) with a diameter of 15 cm showed the highest bearing capacity of 32.44 kPa
with a bearing capacity improvement (BCI) value of 6.151 or a percentage increase in the bearing capacity by
515.09%. On the other hand, the columns (clay + RHA) with a diameter of 3.75 (4 columns) have the lowest
bearing capacity, which is equal to 18.67 kPa.