Experimental Study on Shear Resistance of Carex‐Root‐Fibered Soil

Abstract

Carex shows strong vitality, adaptability, and performance with regard to soil consolidation and slope protection but is often disregarded as a weed. This study proposes to turn this so-called weed into treasure, using its characteristics to protect the slope. We studied the interaction between the carex roots and soil and compared it to other types of grass. To understand the interaction between the carex roots and soil, this study investigated the tensile properties of the carex root fibers. The effects of fiber content, humidity, distribution, and soil moisture content on the relationship between the shear strength and vertical pressure of the soil were analyzed using a direct shear test. Furthermore, the cohesion and internal friction angle were used to evaluate the shear strength of the root-fibered soil based on Mohr–Coulomb’s law. The results showed that the smaller the diameter, the shorter the length, and the greater the quantity and the lower the humidity of the root fibers, the higher the tensile strength of root fibers. In addition, the soil strength could be improved by the joint action of the roots and the soil. With an increase in the root fiber content and humidity, the soil moisture content decreased, whereas the shear strength of the carex-root-fibered soil increased. Here, four kinds of root fiber distributions, namely, “glyph,” “herringbone,” “eccentric,” and “vertical,” were chosen to study the shear strength of the root-fibered soil. The results showed that “glyph” root fiber distribution had the highest shear strength, while the shear strength decreased for the others.

Influence of root distribution patterns on soil dynamic characteristics

“…Lian, B's study shows that the individual horizontal and vertical arrangement is not as effective as the crossed arrangement because it is reinforced in only one direction compared to the crossed arrangement. Moreover, the reinforcement effect of vertical roots is better than that of horizontal arrangement 24 . In this paper, the diameters and lengths of the root systems added in the experiments were selected according to uniform criteria, and the basic difference between the two root distribution patterns was the proportion of roots in different directions.…”

“…Regarding the study of root distribution properties, Zhang et al 22 and Lian et al 23 investigated the effects of three analytical distributions, vertical, horizontal, and cross, on the shear strength of root-soil complexes by triaxial compression tests and suggested that the enhancement effect of cross root distribution was optimal. Wang et al 24 tested four types of herbaceous…”

Research on the mechanism of plant root protection for soil slope stability

“…When the slope loses water the soil shrinks and consequently fissures are created. Repeated expansion and contraction lead to the loosening of the swelling soil and t form many irregular fissures in it, thus creating conditions for further erosion of the soil surface [12][13][14][15]. In the event of rainfall infiltration, it is very likely to lead to geological disasters such as landslides [16][17][18][19][20].…”