Parametric analysis of rigid inclusion configurations and their effects on embankment deformation

Abstract

Soft soil often poses significant challenges for infrastructure construction in Indonesia because of low bearing capacity and excessive settlement characteristics. One effective solution to address this issue is soil improvement. Several methods are available in practice, including rigid inclusion (RI), deep soil mixing (DSM), and Prefabricated Vertical Drains (PVD). The selection of the appropriate method generally depends on the type of existing soil, construction costs, duration, and availability of materials. This study discusses the soil improvement design for a Toll Road project in Banten province, Indonesia using the rigid inclusion method. The design must meet the requirement criteria for soil settlement and embankment stability. A parametric study with various configurations was conducted to determine which model is more efficient. Different rigid inclusion spacing, pile length, and height of embankment were considered in the study. The results show that the settlements were effectively reduced with moderate column length and closer spacing, particularly for higher embankments. For lower embankment with height less than 6 m, the spacing ranging from 2 to 2.2 m seems to be reasonable for an optimum rigid inclusion configurations. For longer column with the length twice as the soft clay thickness, the effects of spacing on the settlement were minimal.