Problems and tactics for the culvert modifications of roads in mountainous areas

Roads in mountainous areas have varied topography, thus culverts have to be frequently modified due to the position, ground base and numbers, while culverts project bills are calculated based on culvert meters according to National Bids Document Model for Road Projects, which brings about some inconvenience, even disputes. The authors of this article have presented such methods as adding sections to model bill projects that helps solve similar modification problems effectively.