Research purposes: The different levels of elevation control network for a line sometimes needs to be established in railway construction due to difference of structures, the current practice is to take the measurement by stages and adjust respectively, and there are two problems. Firstly, the measurement of different stages results in repeated ones, and increases the investment. Secondly, the broken difference of level arises after two measurements, it is eliminated by adjusting the longitudinal section of subgrade. It causes inconvenience to engineering construction. To solve the problem, the paper proposed the solution which is establishment of unequal precision railway leveling network for one time.
Research conclusions: According to theoretical research and the practice, the paper put forward the establishment of unequal precision railway leveling network for one time, and studied the layout and observation method of unequal precision control network. The paper deduced the comprehensive weighting method using different levels of precision and length of leveling line, and carried out adjustment calculation and contrast analysis with project cases. The results show that the weights-making and adjustment method of unequal precision railway leveling network is correct. Elevation achievement after adjustment satisfies the needs of different section, different levels of elevation control surveying accuracy in the railway engineering. Through the establishment of the unequal precision railway leveling network, it optimizes the organization of production and decreases the investment. It deserves to be applied and generalized in the field of railway elevation control survey and helpful for improvement of the leveling content in the code for railway engineering survey.
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