Mechanical modeling for precast trapezoidal canal under the influence of bi-directional frost heave and field experimental verification

Precast lined canals are important water conveyance structures; however, they often suffer severe frost heave hazardous in cold regions. Currently, the frost heave design of precast canallining canals mostly depends on engineering experience, and the analytical mechanical model under the frost heave action of foundation soil is seldom studied, which leads to a deficiency in existing design. First, the frost heave characteristics of the canal are analyzed, and the canal lining structure is regarded as simply supported beam. Then, the frost heave mechanical model of precast lining canal under bi-directional frost heave is established, and the bending moment and deflection are deduced. The accuracy of the model is verified by comparing with field monitoring test data. Finally, the frost heave law of the precast lining canal is revealed by parameter analysis. The results show that the bi-directional frost heave calculation method should be employed in shallow ground water, while the ordinary frost heave calculation method can be selected for deep ground water. The maximum displacement at the joint of the precast lining is 2.42 cm, less than 3 cm permissible displacement, whereas that of the cast lining is 1.65 cm, which is 46.67 % higher than that of the cast plate, the frost heave displacement of the cast-in-place plate is greater than 1 cm. This clearly demonstrates the superior deformation capacity and frost resistance. The research results can provide a theoretical basis for frost heave design of precast lining canals in cold regions. •A frost heave mechanical model is constructed for precast slab of trapezoidal water conveyance canal under bi-directional frost heave.•The influence of joint position change and joint filling material on frost heave deformation of slope plate is clarified.•The influence of groundwater level change on the internal force of lining plate is considered.