Experimental Study On TDA Pospone Ballast Deterioration Under Impact Load

Heavy-haul railway,as an important part of China’s railways,is an important channel for transporting goods and plays an important role in the transportation field.Heavy-duty railway track bed is usually composed of gravel with certain gradation.In the process of train running,the existing ballasted track often suffers from the impact load transmitted from top to bottom due to the rough rail or ratchet wheel.Under the impact load,the ballast particles will be degraded such as splitting and wear,so a large number of fine particles and dust will be produced.These fine substances will cause the blockage of the ballast bed pores,and then degrade the mechanical properties of the ballast bed,and make the longitudinal stiffness of the ballast bed unevenly distributed,which can seriously cause the phenomenon of frost boiling and mud caving.As a waste material,waste tires will seriously pollute the environment and endanger human life and health if they are not handled properly.In this paper,tire-derived aggregate(TDA)is applied to delay the deterioration of ballast.Through indoor impact test,the law of TDA delaying the deterioration of ballast is explored,and the optimal dosage is obtained.The specific application method is to add two kinds of substances according to different volume ratios,and compare them with those without TDA.The main research contents of Wen Zhang are summarized as follows:(1)In this paper,the impact tests of ballast samples with TDA content of 0%,5%,10%,15% and 20% were carried out.The hammer weight was 30 kg,the falling height was 50 cm,the falling way was free fall,and the impact times were 200 times.According to the difference of ballast gradation before and after the test,three deterioration indexes,BBI,Bg and FI,are put forward to measure the deterioration of ballast before and after the test under different TDA content.From the above three aspects,the optimal dosage of TDA is determined to be 15% by volume.(2)In this paper,the displacement monitoring device based on DIP technology is used to measure the maximum impact displacement of ballast samples with different TDA content under impact load,and then the variation law of the maximum impact displacement during 200 impacts and different TDA content is obtained.It is found that with the increase of impact times,the index shows a trend of increasing at first and then decreasing.From the peak displacement under five working conditions,the optimal dosage of TDA is determined to be 15% by volume.(3)In this paper,the graphic analysis method based on 3D scanning technology is adopted,and the deterioration of ballast and the delay of TDA to the deterioration of ballast are explored from the meso-level.Three-dimensional scanning was carried out on 24 selected ballast particles before and after the test.The volume loss rate,shape coefficient,average wear depth,maximum wear depth and crushing index of ballast particles with different TDA content were analyzed,and the optimal TDA content was determined to be 15% by volume.In this paper,through the reasonable use of TDA,from all aspects of the indicators,the volume ratio of 15% of the dosage can effectively alleviate the impact load caused by the deterioration of ballast.The conclusion can be referred to the effective use of TDA in the project,so as to extend the service life of the ballast track and ensure the safety of the train.At present,China’s rubber industry is promoting building energy conservation,emission reduction and recycling economy,green demonstration of reclaimed rubber production line,this article conclusion for recycling waste tyre nearly reuse,provide a reliable theoretical support and reference value,is the energy conservation and emissions reduction,a fully embody the circulatory use of resources,has the very high popularization value.