公轨两用过江通道桥隧方案比选

分析了某规划为轨道交通与城市快速路公轨两用过江通道的建设规模和地质条件，重点调查了岩溶发育及特征，提出了具备一定可行性的桥梁和隧道方案。通过对规划用地、交通功能、地质条件适应性、运营安全、经济性，以及对水保区、通航、行洪的影响等方面的比选，最终认为位于岩溶发育区、紧邻一级水源保护区的过江通道采用隧道方案有较高的工程风险和社会风险，而桥梁方案建设费用低，能够满足通航和行洪要求，且设计理论完善，施工经验成熟，对地质条件的适应性较强，具有较高的工程可行性。因此，工程可行性阶段推荐采用公轨两用的桥梁方案。

Comparison and Selection of Bridge and Tunnel Schemes for Highway-rail Dual-use Crossing-river Channel

The construction scale and geological conditions are analyzed for the planning of a highway-rail dual-use crossing-river channel of rail transit and urban expressway. The development and characteristics of the karst are specially surveyed. The bridge and tunnel schemes with some feasibility are put forward. Through the comparison and selection of the planned land, traffic function, adaptability of geological condition, operation safety, economy and the influence on water protection area, navigation and flood discharge, finally, it is considered that the crossing-river channel located in the karst developed area and close to the Class I water conservation area has the higher engineering risk and social risk if using the tunnel scheme, but the bridge scheme is good because of its low construction cost, which can meet the requirements of navigation and flood discharge. Its design theory is perfective, its construction experience is mature and its adaptation to the geological conditions is high with the high engineering feasibility. Therefore, the highway-rail dual-use bridge scheme is recommended in the engineering feasibility stage.