Caractérisation des matériaux constitutifs de plate-forme ferroviaire ancienne

Trinh, Viet-Nam; Tang, Anh Minh; Cui, Yu‐Jun; Canou, Jean; Dupla, Jean Claude; Calon, Nicolas; Lambert, Julie; Robinet, Alain; Schoen, Olivier

doi:10.1051/geotech/2011134065

Cited by 16 publications

(11 citation statements)

References 14 publications

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“…The results show that the sub-grade is high-plasticity silt. More details about the characterization of the interlayer soil can be found in Trinh et al (2011).…”

Section: Materials Studiedmentioning

confidence: 99%

Effect of fine particles on the hydraulic behavior of interlayer soil in railway substructure

et al. 2014

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The conventional railway substructure in France was built by emplacing ballast directly on subgrade. Over years of operation, the interpenetration of ballast and subgrade created a soil layer between them. Under different conditions, this naturally formed layer, namely interlayer, can contain different quantities of fine particles, becoming more or less sensitive to changes in water content. As the water content changes are governed by the hydraulic behavior of the interlayer soil, assessing the influence of fine particle content on the hydraulic behavior of interlayer soil is of importance. To this end, the hydraulic behavior of an interlayer soil taken from Sénissiat (near Lyon, France) was investigated using two infiltration columns, a large-scale column equipped with tensiometers and a time domain reflectometer (TDR) for suction and volumetric water content measurements, respectively, and a smaller column equipped with high-capacity tensiometers only. Different fines contents were considered and wetting–drying cycles were applied to the soil specimens. The hydraulic conductivity was determined by applying the instantaneous profile method. The results obtained showed that (i) hysteresis exists for both the soil water retention curve and the hydraulic conductivity changes with suction; (ii) the effect of wetting–drying cycles is insignificant; (iii) adding 10% fine particles to the natural interlayer soil gives rise to changes in the soil water retention curve but does not induce significant changes in hydraulic conductivity; (iv) the unsaturated hydraulic conductivity of interlayer soil with 10% fine particles added is close to that of soil sieved at 2 mm, suggesting that the unsaturated hydraulic conductivity of interlayer soil is mainly governed by fine particles through the suction effect. By contrast, in a saturated state, the value for the interlayer soil with 10% fine particles added was found to be higher, suggesting that in this case the hydraulic conductivity is mainly governed by the water transfer through macropores.

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“…The results show that the sub-grade is high-plasticity silt. More details about the characterization of the interlayer soil can be found in Trinh et al (2011).…”

Section: Materials Studiedmentioning

confidence: 99%

Effect of fine particles on the hydraulic behavior of interlayer soil in railway substructure

et al. 2014

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“…During the renewable program for conventional lines, this layer was maintained since the dry density of the interlayer was as high as 2.4 Mg/m 3 and thus a favourable mechanical behaviour was expected [7]. According to the in-situ investigation, the soil fabric of the interlayer is found to be greatly dependent on the content of ballast grains [37,38]: the ballast grains are in contact with each other for the upper part with high ballast content, but floated in the fines matrix for the lower part with lower ballast content. Since the ballast/fines mixture plays an important role in the overall behaviour of rail tracks, it is important to investigate the mechanical response of such mixture under cyclic loading in terms of permanent deformation and resilient modulus.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the parallel gradation method based on the response of track-bed materials under cyclic loadings

Cui

Dupla

et al. 2020

Transportation Geotechnics

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Ballast/fines mixture is often found in railway substructure and the overall behaviour of tracks is strongly dependent on the mechanical behaviour of this mixture. Since directly testing such mixture with large grains is limited with common laboratory equipment, the consideration of a model material at smaller size is advisable. Parallel gradation method is widely used for this purpose. This study assesses the validity of this method in the case of ballast/fines mixture. Large-scale cyclic triaxial tests were carried out on the ballast/fines mixture at six volumetric coarse grain contents. The results obtained were analysed, together with those obtained previously from small-scale triaxial tests on a microballast/fines mixture whose microballast grain size distribution was determined by applying the parallel gradation method. The cyclic parameters (permanent strain and resilient modulus) were obtained for the two types of mixture. Results show that for all mixtures two distinct soil fabrics can be identified according to the variations of permanent strain and resilient modulus with the volumetric content of coarse grains fv: a fine-fine contact structure for fv ≤ 20% and a grain-grain contact structure for fv ≥ 35%. In the case of fine-fine contact structure, the permanent strains and resilient modulus values of the ballast specimens are consistent with those of the microballast specimens, evidencing the validity of the parallel gradation method. In the case of grain-grain contact structure, the permanent strains and resilient modulus values are found to coincide globally at the two scales, also justifying the validity of the parallel gradation method, the slight differences between the two scales being attributed to the irregular grain sliding and the 3 distribution of the fines soils.

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“…1) shows that the fouled ballast (FB) corresponds to a poorly sorted material constituted of large grains (up to 60 mm) from the ballast layer and of fine grains (clay). More details can be found in Trinh et al (2011). The curve of the fouled ballast shows that the percentage of soil particles smaller than 2 mm was 26%.…”

Section: Methodsmentioning

confidence: 98%

Unsaturated Soils: Research and Applications

2012

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Caractérisation des matériaux constitutifs de plate-forme ferroviaire ancienne

Cited by 16 publications

References 14 publications

Effect of fine particles on the hydraulic behavior of interlayer soil in railway substructure

Effect of fine particles on the hydraulic behavior of interlayer soil in railway substructure

Investigation of the parallel gradation method based on the response of track-bed materials under cyclic loadings

Unsaturated Soils: Research and Applications

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