Projects / Programmes
Optimizacija dimenzioniranja gramozne grede in ostalih nosilnih plasti pod njo, z in brez geomreže (Slovene)
| Code |
Science |
Field |
Subfield |
| 2.01.02 |
Engineering sciences and technologies |
Civil engineering |
Geotechnics |
| Code |
Science |
Field |
| 2.01 |
Engineering and Technology |
Civil engineering |
Researchers (14)
Organisations (1)
Significance for science
In spite of the fact that geogrids have been used for more than 20 years already, there are still a lot of unknown things related to reinforcement mechanism. Thus research project dealed with geogrid – gravel material interaction and their behaviour in reinforced soil composite, which is subjected to traffic loading. Research conclusions help importantly to understand reinforced soil mechanism when such material is built into the railway track. Relationships between small strain stiffness measured by static method (small strain load cycles) and the one evaluated from propagation of shear and longitudinal waves, were researched within the research project. Laboratory tests of geosynthetic reinforced soil have explained the mechanism of lateral confinement, which is caused by geogrid in reinforced soil composite.
A large-scale direct shear test apparatus was modified for the purpose of research work and testing of crucial impact parameters in the scope of presented research project. A real scale testing of single materials, theirs composites and parts of railway track is enabled by this improvement.
Dynamic hollow cylinder device has been used to perform high frequency tests with principal stress rotation. Damaging effect of principal stress rotation on the subgrade soil has been defined based on the test results.
The experimental facilities of The Laboratory for Structure (ZAG Ljubljana) have been used to build in laboratory 15 models of railway track structure, with and without geogrid reinforcement. Empirically defined relations between gravel material thickness, type of reinforcement and type of subsoil will enable optimum construction of railway pavement.
FEM tools have been used to model railway track structure. In the scope of model development an adaptive method of modelling of plates using the method of equilibrated boundary stress resultants was developed. It enables to estimate both discretisation and model error.
Research project pointed out improper characteristics of gravel material which is used on Slovenian railway tracks. Searching for proper substitute, a steel slag as a waste from steel production was recognized as possible choice. Research pointed out high temperature resistance of steel slag, which could be used as an aggregate for fire resistant concrete. Microstructural analysis of samples exposed to high temperatures impact promotes the theory that steel slags could be used as fire resistant aggregates. This characteristic of material is important in case of use in railway tunnels.
Significance for the country
An efficiency of economy of every developed society strongly depends upon an activity of its traffic system, because it directly influences on promoting or limiting and even braking of development of society as a whole. The railway infrastructure is an important part of this system. Its modernization is prerequisite for more suitable including of Slovenia to European traffic net, for more favourable flux of passengers, goods and service between Slovenia and other European states. An characteristic traffic position of Slovenia and an increasing of a road transit traffic at the same time, is an important factor of preservation of the environment and the place. It can be one of the comparative advantages of Slovenia in European traffic environment. The existent railway lines, mostly built in a former century aren't suiting any more for the contemporary transport needs. These needs are higher speed, higher frequency of trains and bigger reliability. National program (NPRSZI), among other things, includes also new projects like a rapid railway line Trieste - Ljubljana - Zagreb with connections to Koper and Rijeka and second track Ljubljana – Jesenice.
Due to its its geographic position, Slovenia is directly connected with a traffic system of European Union . Orientations in traffic EU policy request adaption of our traffic economy urgently, as this is one of the conditions for most favourable estimation of geographical position and in the same time condition for equally participation of Slovenian traffic system in the European traffic system.
Strategy of the development of the European railway infrastructure, of which part are also the main lines of Slovene railway system, is determined in details in following European documents:
- UIC; International railway association:”Perspective plan of development of European railway infrastructure”, Paris, 1974, 1990
- GEB; Community of European railways:” European net of lines for high speeds”, Brussel, 1991,
- UN – ECE; Economic committee of United Nations: European agreement about the most important international railway lines – ACG” Geneva, 1985.
It is evident from presented papers that an entire traffic cross of the Slovene railways Jesenice-Dobova and Koper – Šentilj including programs Divača – Sežana and Pragersko - Središče, are of an international importance.
Higher stiffness of railway tracks, which are essential for managing train speed of 160 km/h, is one of the conditions that the states which signed those documents, among them also Slovenia, have to consider for the larger reconstructions and new constructions of the main railway lines. High technical demands in combination with very heterogeneous geological conditions and stirring topography quite often causes significant increase of costs.
The use of new materials and technologies, which were researched within this research project, will contribute to reducing the costs of investments. Geosynthetic manufacturer will implement research project results into practice. In fulfilling this task, they as well as railway managers will be assisted by reference field test sections build in the scope of this research project.
ZAG as an accreditation body with recognized qualification for testing and confirming of geosynthetic material to the European standards, is required also to implement new testing procedures and to develop new technologies as well as enable their quick transfer into practice. Recommendations and guidelines for design of ballast railway track reinforced with geogrids, which were writen within this research project, additionally help Slovenian Railways to achieve the transfer of knowledge into practice. Novel regulations for upper layers of railway track design were completed with a help of this recommendations for the time of project duration, while novel regulations for lower layers of railway track design are still in preparation.
Most important scientific results
Annual report
2009,
2010,
2011,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2009,
2010,
2011,
final report,
complete report on dLib.si
