Past research
Lateral resistance of ballasted tracks for various shapes of sleepers based on limit equilibrium methods
In this study, limit equilibrium methods were focused to evaluate lateral resistances of railway ballasted tracks. Lateral resistances under single-sleeper pull-out loadings as well as those under track-panel pull-out loadings were estimated for various shapes of sleepers. The lateral resistances were compared with those obtained from model tests. It was found that the limit equilibrium methods could well predict lateral resistances not only for a rectangular parallelepiped-shape sleeper but also for winged-shape sleepers having rectangular or trapezoid cross sections. It was also found that lateral resistances of various numbers of sleepers under track-panel pull-out loadings could be reasonably predicted by the methods.
Deformation characteristics of fresh and fouled ballasts subjected to tamping maintenance
A number of train passes over time induces large settlement on ballasted railway tracks. Tamping maintenance application, which is practised worldwide, can lead to additional subsequent track settlement from the disturbances caused by the tamping tools. In this study, a series of model tests on a scaled-down ballasted railway track was conducted to examine the settlement characteristics of ballast subjected to tamping maintenance application. The particle movements during cyclic loading were tracked using a particle image velocimetry (PIV) approach to study the local deformations induced by the tamping tools. The results revealed that the intrusion of fouling material and subsequent maintenance application altered the settlement characteristics significantly. The PIV results revealed that the top ballast is loosened by the tamping tools. It was also found that the strength properties of ballast deteriorate with the fouling of the material. Notably, the strain hardening behaviour of ballast is weakened when the material undergoes 30% fouling or more according to the fouling index, FIp (i.e., an indication of degree of ballast fouling). The results of this study suggest that track maintenance should involve the tamping of fouled ballast before FIp reaches 30%.
Study on Physicochemical Properties and its Effective Use of Asphalt Pavement Cutting Waste Water
While cutting asphalt pavement surfaces, cooling water is continuously given to the cutting machine blades to prevent the heat increase and to control the scatter of cutting dusts. As the results, asphalt pavement cutting waste water is generated. The amount of waste water generated at one construction site is by no means a lot, however, the water quality is not environmentally friendly. In view of above, the physical and chemical properties of cutting waste water were first investigated. Then the possibility of effective use of the cutting waste water was investigated using flocculants and granulation technique. The results show that the waste water quality can be improved by the effects of flocculants. Mud sediments after flocculated in the waste water can be granulated and the granules may be used as recycled sands or recycle crusher-runs aggregates.
A New Granulation Method with the Process of Crumbling Partially-cemented Liquid Muds and its Application to a Motocross Track
A new method for granulating liquid muds was proposed. This method involves the crumbling of partially cemented muds. The crumbling is the re-stirring of the cement–mud mixture when certain time elapsed after the cement was added to the liquid muds. Laboratory experiments revealed that the cone indices of the cement-mud mixtures measured after they are primary cured can be used to control the possibility of granulation and the particle size of granules obtained. The test results also indicate that the granules show high potential for use in materials such as reclamation, subgrade or backfill materials. The application of this crumbling granulation method in the maintenance work of a motocross track was also presented in this study.
