Research On The Design Of Heavy Haul Railway Sleeper Based On Ultimate State Method

In order to cope with the rising of energy cost and adapt to the rapidly development of transportation industry, our country need to put forward higher requirement on the construction of heavy haul railway. Sleeper as an important component structure of railway track, also need a higher requirement to improve. Although the existing design method of railway concrete sleeper has already considered many influential factors in calculation, these factors are assumed based on engineering experience. This method has obvious shortcoming in theory, can not reflect the real situation. So the ultimate state method of heavy haul railway sleeper design is presented in this thesis.The 30 t axle load heavy vehicle dynamics model was established by the dynamics simulation software, the model considered the track irregularity. Using the sensitivity analysis method to analysis and calculates the sensitivity of various factors on wheel-rail force. And the vehicle speed, the vertical and transverse stiffness of railway track and the vertical stiffness of spring on each side of bolster were confirmed as sensitive parameters. These parameters were treated as random variables which obeying normal distribution to simulate and analyze the distribution characteristic of wheel-rail force. The theory of probability and statistics is used to analysis the probability distribution characteristic of wheel-rail force and its maximum. The probability distribution of random wheel-rail force obeyed the normal distribution and the maximum wheel-rail force obeyed the extreme Ⅰ type distribution checked by χ2 condition in the significance level of 0.05.To considered the relationship between gauge and transfer coefficient that transferred from wheel-rail force to sleeper. The maximum sleeper distribution of dynamic pressure on sleeper obeyed the extreme Ⅰ type distribution, and it’s same with the distribution of maximum wheel-rail force. Simplified the actual situation of sleeper supporting and got the supporting calculation schema of it. Then calculated the distribution characteristic of load effect.The calculation method of sleeper resistance was reviewed in this thesis. The sleeper resistance was calculated by its static cracking load. And they both had the same distribution.According to the destruction type of sleeper, put forward two kinds of failure modes(the transverse crack of section and concrete crushing) of sleeper and determined the function and ultimate state equation of each failure mode. Then put forward the suggested values of subentry coefficient of each variable based on the theory of ultimate state design method. The influence of sleeper weight was ignored in the calculation. The suggested value of load effect subentry coefficient was 1.05 and the suggested value of resistance subentry coefficient was 1.14.According to the principle of ultimate state, the reliability index of Ⅲ concrete sleeper which was corresponded the failure mode caused by bending moment was analyzed by JC method and subentry coefficient calculated by this thesis. The result showed that the Ⅲ concrete sleeper can be used in heavy haul railway.