Experimental study on hydrophysical properties and slope planting of ecological composite material solidified loess

The construction of engineering projects in the Chinese Loess Plateau has resulted in large areas of exposed slopes, increasing the risk of soil erosion. Restoring the slope ecosystem is an effective means to reduce soil erosion, prevent soil and water loss, and maintain slope stability. Ecological slope protection using bio-gum solidified fiber-reinforced loess (GFSL) has been proven to achieve good vegetation restoration effects, but there remains a problem of low vegetation coverage in the early stage of protection. Therefore, it was proposed to use bio-gum, artificial fiber, coco coir (CC), and wood wool (WW) to configure ecological composite material solidified loess (ECMSL). By conducting soil-water characteristic tests and outdoor slope planting model tests, the hydrophysical properties and vegetation restoration effects were studied. The results showed that compared with GFSL, ECMSL had a reduced percentage of large and medium pores and an increased percentage of small and micro pores, which demonstrated better hydrophysical properties and could provide more water for plant germination and growth. The hydrophysical properties of ECMSL increased with the increase of CC content and first increased and then decreased with the increase of WW content. When the content of CC and WW was 1.5% and 1.0% respectively, the properties of ECMSL were optimized. Compared with the GFSL protected slope, the short-term vegetation coverage rate of the slope protected by the optimal proportion of ECMSL was significantly improved, and the plant growth indices of the plants were also better. Overall, ECMSL can provide a better growing environment for plants, thus restoring the slope ecosystem faster and improving the effect of short-term plant slope protection. Furthermore, the field application of the ecological materials presented in this paper was effective, suggesting they can be promoted in engineering projects. The results of the study can provide an important reference for ecological protection projects and related research in loess areas.