Laboratory study on the use of EPS-block geofoam for embankment widening

Abstract

The use of expanded polystyrene geofoam (geofoam block) has been gaining momentum in roadway expansion projects. They are traditionally placed along the slope face of the existing roadway embankment as a side-hill fill. However, previous studies have shown the detrimental effects of seepage forces on the side-hill fill type of geofoam block configurations. In order to improve the performance of traditional embankment-widening configuration under seepage forces, an alternative geofoam block assembly is proposed. For this purpose, a lysimeter with dimensions of 60 cm high, 20 cm wide, and 200 cm long was constructed in the laboratory. A water reservoir located at the end of the lysimeter provided three different constant pressure heads (25 cm-, 38 cm-, and 50 cm-H 2 O pressure) during the tests. An embankment-widening geofoam block assembly was placed along the slope face of marginally stable sandy embankment to investigate the effects of seepage on the stability of geofoam block assembly. The dimensions of the geofoam blocks used to construct the embankment-widening sections were 2.5 cm high, 5 cm wide, and 15 cm long. In addition to the laboratory physical testing, factors of safety against global stability and hydrostatic sliding failures were studied through coupled numerical modelling. Stability modelling comprised fully coupled variably saturated flow and conventional limit equilibrium analysis to quantify the performance of the lysimeter test against global stability failure. Factor of safety against hydrostatic sliding was quantified using fully coupled variably saturated flow and stress-deformation modelling. Both laboratory and numerical models showed that the proposed geofoam block configuration significantly improved the performance of traditional side-hill fill embankment-widening technique under seepage forces.

Experimental investigation of sandy loam soil erosion on a 45-degree slope under the effect of groundwater flow

“…[16], [25]- [29], Akay [30], Özer ve diğ. [31]- [32], Özer [33] tarafından kullanılmış iki-boyutlu erozyon kanalı üçboyutlu hale getirilerek literatürde kullanılmamış kohezyonlu doğal topraktan oluşan bir şevin sızma suları altındaki davranışı boşluk-suyu basınç ölçümleri ışığı altında incelenmiştir.…”

Interlocking Settlement Induced by Widening Subgrade of Railway Line

“…Field investigations [4], small centrifuge tests [5], and numerical analyses [6,7] have been conducted to analyze the deformation characteristics and mechanisms of widened embankments. As a result, geotextile reinforcements [8,9], geosynthetic clay liners [10], foundation columns [11], lightweight stacking materials [12,13], and combinations of these methods [14,15] have been proposed to solve problems that may occur in widened embankments.…”

Deformation Characteristics of Raising, Widening of Old Roadway on Soft Soil Foundation

“…Lu [21] proposed a maximum allowable differential settlement of 5.44 cm for an integrated pavement structure. Zhang [22] explored the reconstruction project of the Yan'an North Transit Line to analyze the differential settlement characteristics of the widened subgrade, the control standard of differential settlement for subgrade widening, and the rationality of wet and soft ground treatments via numerical simulation and field test According to Ozer [11], the structure of geofabric blocks can significantly improve the performance of traditional edge hill widening technology under seepage force. Phutthananon [12] found that the effect of soft soil layer thickness on differential settlement is not significant, but on average, settlement is significant; the effect of pile strength on differential settlement is significant only when the pile cap size is relatively small.…”