Multi-field coupled analysis of a composite ecological lattice anchorage system for protecting expansive soil slopes

Purpose The purpose of this study is to examine the protective efficacy of the composite ecological lattice anchorage system (CELAS), which comprises a grid, anchor rods, high-performance vegetation protection mats and vegetation, on expansive soil slopes subjected to rainfall, along with its principal influencing factors. Design/methodology/approach A multi-field coupled numerical analytical approach for the moisture, deformation and stress fields was created for expansive soils. Based on this method, a multi-field coupled analytical model for CELAS protection of expansive soil slopes was developed. The model’s accuracy was confirmed by juxtaposing test findings with numerical simulation outcomes. This model was used to assess the protective efficacy of CELAS and its affecting elements. Findings CELAS efficiently restricts the deformation of expansive soil inclines. Under rainy conditions, the maximum displacement of slopes protected by CELAS was reduced by 46% compared to unprotected slopes and by 35.6% compared to slopes protected just by lattice anchorage systems. CELAS markedly improves slope stability, resulting in a 76.5% increase in the stability coefficient of slopes safeguarded by CELAS compared to unprotected slopes and an 18.3% increase compared to slopes reinforced by grid-type anchorage systems. CELAS proficiently regulates deformation and improves stability across various slope gradients. Moreover, modifying anchor rod parameters can enhance the protective efficiency of CELAS. Originality/value This study presents the CELAS system and a multi-field coupled numerical analysis method that offer an effective ecological protection solution for expansive soil slopes. The results of this research provide a reference for the promotion and application of CELAS in actual engineering and optimised design, as well as a valuable reference for practical work in related fields.