Research purposes: Whether the lapping effects between adjacent sections are reasonable as well as smooth or not have been a predominant influence in achieving high-precision for CP III control network, and will affect the track regularity further. In current code there are problems over practical maneuverability use while using constrained adjustment technique for overlapping points. Therefore a comparative research on lapping methods is conducted combining with engineering practice so as to develop a new lapping method between adjacent sections for CPI(I track control network.
Research conclusions: (1)It is feasible to use cosine function smoothing method for CP III lapping between adjacent sections，and the performances of cosine function smoothing method are superior to constrained adjustment method in terms of long waves of the track regularity and relative accuracy.(2)The proposed method，which is designed to perform constrained adjustment on the basis of cosine function smoothing for the lapping points，would help to improve the performances of the track regularity of the short waves as well as the railway line regularity of the overall long waves. (3)It is validated that the research results can meet the practical requirements of engineering surveying and can be applied to CP III lapping between adjacent sections over the ballast less track construction stage as well as operating and maintenance stage. The research also provides a reference for the perfection of the specifications for CP III lapping between adjacent sections and related measurement.
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