Influence of the Bituminous Layer on Temperature and Water Infiltration in Railway Structures of the Bretagne–Pays de la Loire High-Speed Line

Abstract

Influence of the bituminous layer on temperature and water infiltration in railway structures of the Bretagne -Pays de la Loire high-speed line.The phenomena of settlement and wear of the ballast under dynamic stresses lead to high frequencies and high maintenance costs on high speed railway lines.Studies have shown that these settlements are linked to high accelerations produced in the ballast by the passage of high-speed trains (HST). A layer of asphalt concrete (GB) was introduced under the ballast layer on the high-speed line Bretagne-Pays de Loire (BPL HSL). It is intended, among other things, to reduce the amplitude of accelerations produced at the passage of the HST, and thus improve the durability of the track.The BPL HSL spans 105 km with a sub-layer of asphalt concrete under the ballast, and 77 km with a granular sublayer (UGM). To evaluate the performance of the structures with bituminous sublayer, and to compare it with traditional structures, with granular sublayer, 4 track sections have been instrumented during construction. This article presents the different sensors of the instrumentation as well as the acquisition system installed to collect measurements. The focus, in this study, concerns the temperature, water content and vertical settlement measurements made on the instrumented sections. Temperature variations recorded during two years on the railway structure with bituminous sublayer were analysed and compared to those measured on a classical bituminous pavement.Influence of the bituminous layer on water infiltration and track settlements has also been studied.

Research on Observation of Settlement Deformation of Zhengzhou-Jinan High-speed Railway and Information Platform of Observation Data

“…In the future, we will mainly focus on the following two aspects: (1) The settlement deformation mechanism of Zhengzhou-Jinan high-speed railway will be further studied. (2) The early warning mechanism of the platform will be further improved to realize timely warning of acute settlement and large amount of settlement.…”

“…Besides, the water body in the underlying layer will become unstable under the compressional force, which will lead to foundation settlement. When the high-speed railway runs to this position at high speed, it is prone to accidents [2] .…”

Monitoring of railway structures with bituminous and granular sub-layers: Assessment after four years of use

“…The displacements observed on Section 1 (with bituminous sub-layer and sandy soil), are the opposite: settlements are observed during winter whereas the slight surface uplift observed occurs during summer. Khairallah et al [25] already made this observation, but only during the first two years of observation. In summary, Figure 5 illustrates how settlements observed during the four-year study period are very limited for all the sections, ranging from 0.5 to 2.1 mm.…”

Simulation of the dynamic response of high-speed line structures composed of granular or bituminous sub-ballast layers and comparison with in situ measurements from embedded instrumentation

“…Seasonal variations of layer temperatures, water contents and track settlements on the different instrumented sections, over a period of 30 months, were also studied in detail by (Khairallah, et al, 2019b). The role of the bituminous underlay to improve water drainage and protect the platform against rainwater infiltration has been clearly demonstrated.…”