Abstract: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.
