Publicacións

@article{miranda_critical_2021,

title = {Critical length of encased stone columns},

author = {Marina Miranda and Jesús Fernández-Ruíz and Jorge Castro},

url = {https://www.sciencedirect.com/science/article/pii/S0266114421000571},

doi = {10.1016/j.geotexmem.2021.05.003},

issn = {0266-1144},

year  = {2021},

date = {2021-10-01},

urldate = {2021-10-01},

journal = {Geotextiles and Geomembranes},

volume = {49},

number = {5},

pages = {1312–1323},

abstract = {Encased stone columns are vertical inclusions in soft soils formed by gravel wrapped usually with a geotextile. Their critical length is the one where further lengthening of the column provides a negligible improvement and it is therefore not effective to build columns longer than it. This paper aims to obtain common values of the critical length using simplified two-dimensional axisymmetric and full three-dimensional finite element analyses. A uniform soft soil layer with a linear elastic perfectly plastic behaviour is considered for the sake of simplicity. For the studied cases, the critical column length is around 1.3–2.5 times the footing diameter for encased stone columns, and slightly lower for ordinary stone columns, namely around 1.1–1.9. The critical length of the encasement is found to be slightly lower than the critical column length. The value of the critical column length is related to the extent of plastic deformation and that may be used to decide the column length in the design phase without the need of parametric analyses. As a first approximation, a general value of the critical column length of 2 and 2.5 times the footing diameter may be considered for ordinary and encased stone columns, respectively.},

keywords = {Critical length, Encased stone columns, Finite element analyses, Footing, Geosynthetics, Geotextiles, Settlement},

pubstate = {published},

tppubtype = {article}

}

@article{fernandez-ruiz_improvement_2021,

title = {Improvement of the critical speed in high-speed ballasted railway tracks with stone columns: A numerical study on critical length},

author = {Jesús Fernández-Ruíz and Marina Miranda and Jorge Castro and Luis Medina-Rodríguez},

url = {https://www.sciencedirect.com/science/article/pii/S2214391221001185},

doi = {10.1016/j.trgeo.2021.100628},

issn = {2214-3912},

year  = {2021},

date = {2021-09-01},

urldate = {2021-09-01},

journal = {Transportation Geotechnics},

volume = {30},

pages = {100628},

abstract = {The pressure to achieve a higher speed of train operation has increased in the last few years due to the development of high-speed railway lines. In the presence of soft soils, this speed increase is not possible without undertaking soil improvement measures, since the critical speed is lower than the desired speed of train operation. One of the most widely used soil improvement techniques is that of stone columns. In relation to these is the concept of critical length which, up to now, has only been studied for static cases. This research focuses, for the first time, on the enhancement of the critical speed in high-speed railways with stone columns and with special reference to critical length. Moreover, others parameters such as: maximum rail displacement and Dynamic Amplification Factor (DAF) are also studied. Analysing three profiles of ground representative of soft soils, it can be observed how the effect of the stone columns on critical speed is relevant, showing that critical length is different with respect to the three parameters above, the most restrictive one being that which corresponds to the critical speed. The influence of other parameters on the critical length and on the effectiveness of stone columns, such as the area replacement ratio, the dynamic pressure bulb and the existing soil stiffness is analysed and discussed.},

keywords = {3D dynamic numerical model, Critical length, critical speed, High-speed railway lines, Stone columns},

pubstate = {published},

tppubtype = {article}

}