某高速公路K112+500~K119+500段线路优化设计

通过对某高速公路K112+500~K119+500长达7km的线路设计情况的深入分析，提出了改线优化设计方案，由原设计的4座大桥、1座中桥、4座隧道及3.1km路基、2次跨越河流和国道、“三左两右”5段平曲线，优化为2座大桥、3座隧道及1.0km路基、“一左一右”2段平曲线、避开国道和河流，路线长度减少1.0km。隧道增长1711.5双延米，桥梁缩短1079双延米，路基缩短约1.6km。然后从技术、环保、经济、工期及运营方面进行了详细论述，技术上将“曲线取直”，并满足纵坡要求；环保上以“隧代路桥”，减少占用农田20.5hm2；经济上降低工程造价1650.6万元；降低了施工难度和施工干扰，工期可缩短；隧道长度虽略有增加，但线路长度减短、线形更好，利于运营。

Optimization Design on Alignment of K112+500~ K119+500 Section of a Highway

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.