Effect of different concrete properties on frost heave crack in U-shaped canal lining and joint

Abstract

Due to seasonal frost heave of base soil, there were numerous U-shaped concrete canal linings that crack or even fracture in the irrigation area of northern China. Once the canal lining was cracked or fractured, there would lead to seepage and damage of the canal lining. This situation was adverse to water saving irrigation gravely. The U-shaped canal lining includes two parts which contain prefabricated concrete slabs and cast-in-place concrete joints. Based on the features of construction, the concrete characterization included strength and deformation had observably distinction between slab and joint of lining, which resulted the difference in frost heave effect. In this study, the cracks difference between slab and joint was quantified by the experiment of crack observation firstly. Further, the numerical simulation model with concrete damage model and smeared crack approach of frost heave force was established by the experiments of the effective frost heave and concrete mechanical properties. The crack propagation process of different concrete lining slab and joint was analyzed under the change of frost heave force. At the same time, the validity of the numerical model and approach was proven by comparing the results with the experimental. The result showed that the increase of concrete strength had a significant effect on the resistance of U-shaped canal lining to crack by frost heaving. It indicated that the tensile strength of concrete was increased by 48.28% from C15 to C20, and the frost heaving force during cracking was increased by 21.26%. The empirical equations of power function could be used to predict the cracking frost heave force of U-shaped canal lining by the concrete strength. The study provided a new idea for studying the frost heave damage process of different types of canal lining.