Study on the protection of expansive soil slope by composite ecological lattice anchoring system under rainfall

To address the issue of rainfall-induced instability in expansive soil slopes while considering ecological benefits, this study proposes a composite ecological lattice anchorage system (CELAS) consisting of a lattice, anchor rods, a high-performance vegetation protection mat (HPTRM), and vegetation. An indoor rainfall simulation device was used to conduct slope erosion tests under short-term heavy rainfall and slope infiltration tests under light and prolonged rainfall conditions, comparing the protective effects of various methods (no protection, lattice anchor protection, HPTRM protection, vegetation protection, and CELAS protection) on expansive soil slopes. The findings show that the CELAS system significantly reduces runoff and erosion on slopes, effectively preventing runoff-induced degradation across various rainfall intensities and slope gradients. During prolonged rainfall, the CELAS system regulates the internal water dynamics within the slope, thereby minimizing the deformation of expansive soil. In the post-rainfall evaporation phase, the CELAS system helps retain water, alleviating abrupt contraction caused by expansion deformation and minimizing water loss due to moisture fluctuations. Furthermore, the CELAS system facilitates the release of internal expansion potential through minor deformations and transmits residual expansion forces to deeper soil layers through its connection with the anchoring structure, achieving both surface constraint and deep anchorage of the slope. This research introduces novel techniques for protecting expansive soil slopes.