DBPapers
DOI: 10.5593/SGEM2014/B12/S2.131

USING A LIGHT FALLING WEIGHT DEFLECTOMETER FOR THE IDENTIFICATION OF THE SLEEPER SUBSOIL LAYER QUALITY DEGREE IN RAILWAY STRUCTURES

P. Brestovsky
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-08-7 / ISSN 1314-2704, June 19-25, 2014, Book 1, Vol. 2, 1027-1034 pp

ABSTRACT
The paper presents the method of assessing the quality of a newly built sleeper subsoil layer. The method is based on using the light falling weight deflectometer (LFWD) dropped on a bearing plate and causing a deflection in the layer. The currently only applied test for checking the quality of a layer used in the railway construction in the Czech Republic is the plate load test (PLT). It is a test both technically and timeconsuming. One PLT for 200 m of track without a precisely specified place is prescribed for checking newly built sleeper subsoil layers on railway tracks in the Czech Republic. A complex assessment of the layer requires the identification of the worst place of the construction where PLT should be performed. For this purpose, the newly introduced term of the quality degree of the Zz layer obtained by means of LFWD is used. The layer quality degree is the ratio between the bearing plate’s deflection in the layer due to the first impact and an average impact obtained from the fourth, fifth and sixth impact. The paper describes a modified methodology of working with LFWD with an emphasis on obtaining the bearing plate’s deflection. In conclusion, the verification on a real sleeper subsoil construction carried out during the construction of a railway track in the Czech Republic is described.

Keywords: railway, sleeper subsoil, light falling weight deflectometer