Abstract:

Optimized alignment is proposed for K112+500~K119+500 section of a highway after indepth analysis on the original design. The originaldesigned alignment contains 4 large bridges, 1 medium bridge, 4 tunnels, 3.1kmlong subgrade, twice crossing of river and national highway, 3 left plan curves and 2 right plan curves; The optimized alignment contains 2 large bridges, 3 tunnels, 1.0kmlong subgrade, 1 left plan curve and 1 right plan curve. According to the optimized design, the crossing of the national highway and river has been avoided, the length of the alignment has been reduced by 1.0km, the length of the tunnels has been increased by 1711.5 double linear meters and the length of the bridges has been reduced by 1079 double linear meters. In the paper, detailed expatiation is made on the optimized alignment in terms of technology, environment protection, economy, construction schedule and operation. Conclusion is drawn that for the sake of the optimization, more straight alignment is adopted so as to comply with the requirements of the longitudinal gradient better; more tunnels are adopted, which is favorable for environment protection and can reduce farming land occupation by 20.5hm2; the construction cost is reduced by 16506000 Yuan RMB; the construction difficulty is reduced; the construction interference is minimized; the construction period is shortened; although the length of the tunnels is slightly increased, the length of the total alignment is reduced and the alignment is improved, which is favorable for highway operation.