The Effects of Water Content and Dry–Wet Cycles of Weak‐Interlayer Soil on Stability of Clastic Rock Slope

The goal of this paper was to study the effect of water content change of weak interlayer soil on the stability of clastic rock slope. Direct shear tests were used to study the shear strength of weak intercalated soil with different water content and different dry–wet cycle conditions. The stability of clastic rock slope with weak interlayer was simulated under different scenarios. The results show that the strength of the weak interlayer soil decreases with the increase of water content. When the water content of weak interlayer soil was higher than the natural water content, the slope stability factor decreased rapidly with water content. The reduction of cohesion of the weak interlayer soil was found in the first two dry–wet cycles. The internal friction angle was not affected by the dry–wet cycle. The strength of the weak interlayer soil decreased with more dry–wet cycles. The stability factor of the clastic rock slope decreased exponentially, and the attenuation was concentrated in the first two dry–wet cycles. This study found that rainfall infiltration led to an increase in the water content of weak interlayer soil and a rapid decrease in the shear strength, which has been documented in the stability failure of the clastic rock slope with weak interlayer in Guangxi. The simulation also showed that repeated rainfall infiltration and natural desiccation could impact on the stability of newly excavated slopes.