Why vegetation should be planted near railway tracks

Nov 14, 2005

The days may be numbered when railways face excessive and continuous ballast maintenance and costly track drainage following heavy rains. The basic message for railway authorities is not to underestimate the importance of vegetation growing near railway tracks.

Behzad Fatahi, a PhD student and a teaching academic in the Faculty of Engineering at the University of Wollongong with more than four years' of professional experience in the civil engineering industry, has helped develop a comprehensive water uptake model which links civil engineering and botanical science. His research project is under the Co-operative Research Centre (CRC) for Railway Engineering and is supervised by Professor Buddhima Indraratna.

The model simultaneously simulates the suction of ground water through vegetation roots and the evaporation of water from leaves. Soil conditions, type of vegetation and atmospheric conditions are incorporated in the model.

Considering the integrated infiltration-evapotranspiration-suction relationships, the model can predict the influence of vegetation on the ground behaviour and performance of engineering structures.The findings of Behzad's study, backed up by field trials, indicate that due to significant changes in soil moisture content induced by tree roots, soil shear strength will be enhanced.

“Consequently, the model which I have helped develop can improve the design and construction procedures for railway lines, foundations and embankments near native vegetation,” Behzad said.

Behzad said that tree roots provided three independent stabilising functions (1) reinforcement of the soil (2) dissipation of excess pore water pressure and (3) establishment of sufficient suction that increases the strength.

Behzad was one of the recent prize winners at UOW's Higher Degree Research Student Conference in the category of “Frontier Technologies for Building and Transforming Australian Industries”.

The conference produced an opportunity for UOW to showcase its world-class research and give potential students and industry partners the chance to see the range of opportunities available in postgraduate research.

Media please note: Behzad can be contacted on 4221 4816 or 0413 573481 (m) for further information or his supervisor, Professor Buddhima Indraratna on 4221 3046.

For more information, contact:

media@uow.edu.au
University of Wollongong
Ph: (02) 4221 5942; fax (02) 4221 3128