Mechanical Analysis of Frost Heave of Trapezoidal Canal in Frozen Soils with Shallow Groundwater Table

Abstract

【Objective】 Frost heave is a hazard damaging canals constructed in frozen soils with shallow groundwater table. Taking trapezoidal canals with arc bottoms as an example, this paper investigated the mechanisms underlying the formation of frost heave and its dependance on groundwater table depth. 【Method】 The analysis was based on the Winkler assumption and that the height of the arc was much less than overall depth of the canal. We proposed a method to calculate the variation of normal force over the frost heave force, as well as the distribution of tangential freezing force over the curved segments of the canal linings. A mechanical model was constructed to analyze the damages caused by frost heave. 【Result】 The transverse difference in the distribution of the sectional internal force and the frost heave force both increased as the depth of groundwater table decreased. The effect of groundwater table depth on distribution of the sectional internal force and frost heave force decreased as the depth of the groundwater table increased. Adequate time and source for water recharge and transversely uneven distribution of frost heave force are the main cause of frost heave damage to the canals. 【Conclusion】 The proposed model describes the mechanical characteristic of the canals due the impact of frost heave reasonably well, and the calculated are accurate and reliable. The proposed method and results provide a tool to help design canals to improve the resistance against frost heave damages.

Keywords

• frost soil engineering
• irrigation canals
• mechanical model
• trapezoidal canal with shallow arc-bottom
• high groundwater level