Earthen materials have been used as economic building materials since ancient times and continue to be used today, particularly in our modern society that pursues sustainability. As a form of agricultural waste, straw stalks are reused in civil engineering to avoid being burnt, which not only saves costs but also avoids environmental impacts. In the following paper, we present an experimental study on the mechanical properties of rammed red clay reinforced by straw fibers. Straw stalks were cut into different lengths and mixed evenly with red clay in different proportions before being compacted. The compressive strength, flexural strength, and shear strength of the stabilized rammed straw were analyzed. The results show that straw stalks, as a single reinforcing material, can significantly improve the mechanical properties of rammed red clay. Straw stalks had varying effects on improving the mechanical indexes of rammed red clay. When the length of the straw stalks was 15 mm and the straw stalk content was 0 Sust.3%, the straw stalks had the best effect on improving the mechanical properties of rammed red clay.

Rock slope instability is a prevalent geological hazard that imposes significant adverse impacts on engineering activities. Although existing studies have focused on homogeneous rock slopes, the theoretical models for quantifying the stability of soft-hard interbedded anti-inclined slopes remain underdeveloped, primarily due to the complex force transfer mechanisms involved. This study proposed a novel theoretical model for the stability analysis of soft-hard interbedded anti-inclined slopes under rainfall conditions. The framework models stratified rock layers as layered cantilever beams with material heterogeneity. Based on the principle of deformation compatibility, it comprehensively accounted for interlayer force transfer and strength degradation resulting from differential deformations among rock layers. Furthermore, it integrated the critical instability length induced by the self-weight of rock layers to determine the fracture depth. The proposed method was validated against engineering case studies and physical model tests, with error falling within an acceptable range. Compared to existing theoretical methods, the proposed method provided a more realistic representation of the slope’s stress field. The analysis results demonstrate that rainfall not only reduces the inclination angle of the failure surface but also leads to an approximate 30% decrease in the safety factor. The proposed theoretical model is particularly useful for quickly calculating the stability of soft-hard interbedded anti-inclined rock slope under rainfall conditions, compared to complex and time-consuming numerical simulation calculations.