Soft Soil Improvement Using Rigid Inclusions: Toward an Application for Transport Infrastructure Construction in Vietnam

Abstract

Soft soil improvement by vertical rigid inclusions is a widespread technique in France for reducing and homogenizing surface settlements. This technique consists of a rigid inclusion network associated with a granular earth platform (so-called mattress), intercalated between the reinforced soil and the upper structure. The overload is transferred partially onto the inclusions through arching effect occurring in the platform due to shearing mechanisms in the fill. Such a process exhibits an economic and effective solution for large-scale civil works (roadways, railways and industrial building foundations) constructed over soft soils, especially in cases of requiring rapid construction. This paper presents, in the first part, a concise introduction to the soil improvement including general principles, operating mechanisms, calculation rules for the design and execution methods. In the second part, a parametric analysis based on a highway construction project in Dong Nai, Vietnam is rigorously performed to show the influence of different parameters of the technique such as the thickness of the granular earth platform and inclusion diameter on the behavior of a rigid inclusion-supported embankment in the aim of highlighting the functioning mode of the new improvement solution. This leads to a preliminary design solution of soft soil improvement using rigid inclusions for the existing road construction project in Vietnam.