Rehabilitation method of culvert foundation failure using polygeo foam

Abstract

A concrete box culvert with a dimension of 2.1 x 2.1 m and a concrete pipe culvert of 0.9 m diameter founded on soft soil were experiencing soil settlement causing undulation and discomfort to the traffic users. Voids that appeared beneath the culvert foundations triggering the road surface to sag. Objectives of the study are to assess the settlement of culverts underlain by soft soil using PLAXIS simulations on the initial subsoil conditions, after rehabilitation works with Polygeo foam injection and to evaluate the performance of Polygeo foam as a rehabilitation method. The settlement of the culverts underlain by the soft soil will be determined using finite element model based on the data and information obtained from geoforensic assessments including 12 nos. of deep borehole as well as soil laboratory tests. There were six culverts area undergone settlement problem, with two boreholes were executed at the side of each culvert. Throughout the five-year period of Post Construction stage with Polygeo rehabilitation works, the pipe culvert was shown to settle around 22 mm whilst the box culvert with pile settled around 14 mm. The study concluded that the rehabilitation works using Polygeo foam has been successfully reduced the rate of settlement and complied to JKR settlement criteria.