INDIVIDUAL AND GROUP COLUMNS FAILURE OF DEEP CEMENT MIXING (DCM) IN GRATI SOFT SOIL

Abstract

The structural failures were due to the soft soil identified in Indonesia and other countries. Most of them occurred due to negligence, lack of knowledge, and a lack of data sites. The alternative improvement method should meet stability requirements and avoid high costs for structural maintenance. There are some steps to mitigate the failure. First, recognize the potential of soft ground in an area. Second, use the base knowledge to choose a suitable structure for field conditions or make efforts to reduce the risk of collapse. It has soft ground as clayed silt and the potential for slope stability problems in an embankment in Grati soft soil in which the natural moisture content is close to the liquid limit. The Deep soil mixing method will be applied to reduce the risk of collapse on the pavement structure. Portland cement has been a stabilizing material as a binder. The objectives of this study were to identify the potential risk of Grati soft soil and propose steps to mitigate internal and external failure. The result of the laboratory experiment determines that the failure mode of a single column could occur due to the strength of improved soil requiring a high percentage of cement. Adjusting the cement content according to the soil moisture content or the arrangement of columns that are very close to or overlap each other will increase internal and external stability. FEM application for DCM constructions delivers a high safety factor for soil-structure interaction.