山区不良地形条件下互通立交方案研究

Study on Interchange Scheme in Mountainous Areas with Poor Terrain Conditions

摘要:

山区高速公路互通立交在复杂地形、有限空间和生态敏感条件下，面临工程经济、运营安全和环境保护的多重约束。结合湖南省典型山区互通项目，系统开展了常规B型喇叭形、菱形和变异梨形3种互通方案的比选研究。通过构建涵盖线形指标、工程规模、环境影响和安全性的综合评价体系，对各方案进行定量与定性相结合的综合比选。结果表明，在极端地形条件下，变异梨形互通通过立体叠合、曲线分级与桥隧协同等集约化设计策略，在保障交通功能基础上，可实现匝道长度缩短34.6%、挖方量减少30.5%、桥梁规模降低45.1%、占地面积节约46.8%，并具有交通流完全分离和消除冲突点的优势。3种互通方案的设计特点、适用条件和比选方法探讨，可为山区高速公路互通立交的选型及集约化设计提供理论和实践参考。

Abstract:

Under the complex terrain, limited space and ecologically sensitive conditions, the mountainous expressway interchanges are confronted with multiple constraints such as engineering economy, operational safety and environmental protection. Combined with a typical interchange project in a mountainous area of Hunan Province, the comparison and research are systematically conducted on three types of interchange schemes such as the conventional B-shaped trumpet, rhombus and variant pear-shaped. A comprehensive evaluation system covering alignment indicators, engineering scale, environmental impact and safety performance is established to conduct a comprehensive comparison and selection of each scheme combining quantitative and qualitative methods. The results demonstrate that under extreme topographic conditions, the variant pear-shaped interchange can shorten the ramp length by 34.6%, decrease the earthwork excavation by 30.5%, reduce the bridge scale by 45.1%, and save the land occupation by 46.8% on the basis of ensuring traffic functions through intensive design strategies such as three-dimensional superposition, curve grading and bridge-tunnel coordination. And this type of interchange has the advantages of completely separating traffic flow and eliminating conflict points. The design characteristics, applicable conditions and comparison methods of the three interchange schemes are further discussed, which can provide the theoretical and practical references for the selection and intensive design of interchanges in mountainous expressways.