Mechanical effect of three-dimensional reinforced eco-structure on silty sand slopes

The reinforcement turf is a form of slope protection combined with geotextile and grass. It greatly improves the strength of ecological slopes and ensures the ecology and has a wide application prospect. Taking the bank slope protection of silty sand in Tongfu embankment in Heilongjiang Province as an example, the field in-situ tests on 3D reinforcement eco-structure for slope protection and laboratory experiments on the mechanical properties of reinforced soils are carried out, and the mechanical effects are revealed. The experimental results show that: (1) Compared to pure vegetation slope protection and slope protection of surface covering by sunshade net, 3D reinforced turf structure is the most effective for soil reinforcement. The geotextile mat can help vegetation roots to form a good reinforced layer on slope surface, and the vegetation root system helps geotextile mat to be more closely combined with slope soils. (2) The effect of reinforced turf mainly increases the soil cohesion, but has little effect on the internal friction angle. In a growth period, the root reinforcement effect of herbaceous vegetation is concentrated at the depth of 20 cm below the ground. (3) The effect of soil moisture content and root content on the shear strength of root-soil complex is obvious. With the increase of soil root content and moisture content, the shear strength of root-soil complex increases firstly and then decreases or remains unchanged. For the shear-resistant roots, such as tall fescue, there is an optimal root content and moisture content to make the soil strength be the highest.