Stability correction calculation of new debris flow grille dam considering permeation

Abstract

When calculating the stability of a permeable dam under half-full or full reservoir conditions, the seepage force has not been considered in the studies reported in the literature. Based on the equation for the stability of a new debris flow grille dam structure, combined with an accumulation seepage model and the Bernoulli principle, a simplified expression for the seepage force was derived and its effect on the dam body was found to be equivalent to the overturning moment; the original equation was thus corrected. The effect of changing the internal friction angle on stability was analysed, making the corrected equation universal and applicable. Verification results showed that the overturning stability coefficient of the blocking dam was positively correlated with the internal friction angle. Compared with the original equation, after considering the seepage force, the anti-overturning stability coefficient of the blocking dam was reduced by about 44.5% on average. The attenuation amplitude increased with an increase of the friction angle in the accumulation, which was closer to the actual stress situation.