Abstract: To address the influence of constructing the cross-Yinjiang-Jihuai super bridge on the stability of canal-section slopes, and in view of the complex engineering-geological conditions, a limit-equilibrium analytical framework was employed. During the excavation and backfilling of the main-pier foundation pit, the stability of the left and right canal slopes at the bridge-crossing location was evaluated under multiple loading scenarios, including bridge loads, vehicular loads, and seismic actions. The study systematically elucidates the mechanisms and extent to which bridge construction under complex geological conditions affects the stability of canal slopes composed of mudstone containing weak interlayers. Computational results indicate that, under existing stratigraphic conditions and the current construction plan, the safety factor of the canal slopes during the construction stage exceeds 1.2. However, if rainfall or other factors induce further softening of the mudstone, the safety factor may decrease to 1.109, demonstrating that the bridge construction exerts an adverse effect on slope stability and introduces potential safety hazards. A comparative assessment of the two canal banks shows that the left slope exhibits a lower safety factor than the right. This disparity is primarily attributable to geological factors: field investigations revealed that mudstone fracture surfaces on the left slope dip in the downslope direction, whereas those on the right slope dip counter to the slope.

Key words: Water Diversion Project from the Yangtze to Huaihe River, Cross Channel Bridge, Slope Stability, Limit Equilibrium Analysis