LAUSR

In cold regions, deformation because of frost heave in the soil seriously damages the concrete lining of canals, which results in seepage loss and high maintenance costs. Cross‐sectional canal shapes with low‐stress concrete lining are an important aspect of small canal design. Round‐bottom triangular, parabolic and catenary sections are curved and therefore regarded as likely to perform well in conditions in which frost heave occurs. This study provides an objective answer to the question of which section would perform well in frost heave conditions with as large as possible water conveyance efficiency. The design process of small canals was simplified first, and the result shows savings in the land area required for canals. Then, based on two principles, the hydraulic radius and performance of three sections in resisting frost heave damage were compared. In regions without frost heave, the round‐bottom triangular section is better because it has the largest hydraulic radius and design flexibility. In cold regions, if width to depth ratio or depth is a principal constraint, a parabolic (wide section) or catenary (narrow section) is better for big side slopes and curved structures. If side slope (horizontal to vertical) is the principal constraint, the round‐bottom triangular is better. © 2019 John Wiley & Sons, Ltd.