Impact of Plant Root Morphology on Rooted-Soil Shear Resistance Using Triaxial Testing

Suyun Meng,Guoqing Zhao,Yuyou Yang,Xinyu Ye

doi:10.1155/2020/8825828

Abstract

Mechanical reinforcement by plant roots increases the soil shearing strength. The geometric and distribution characteristics of plant roots affect the soil shearing strength. Current research on the shear strength of rooted-soil is mostly based on direct shear tests with a fixed shear surface and thus cannot reflect the actual failure state of the rooted-soil. In this study, Golden Vicary Privet was used to create a rooted-soil, and a triaxial test method was used for soil mechanical property analysis. The influence of the root geometry (root diameter and individual root length) and distribution characteristics (root density and root distribution angle) on the rooted-soil shearing strength was studied by controlling the root morphology in the specimens. According to the results, both the root geometry and distribution characteristics affect the rooted-soil shearing strength. For a fixed total length of the roots, the longer the individual root length is, the better the soil shearing strength is. In addition, the reinforcement effect of the root system increases as the angle between the root and the potential failure surface increases. The results also show that the root system significantly enhances the soil cohesion while only minimally affecting the internal friction angle. The maximum rooted-soil cohesion is 2.39 times that of the plain soil cohesion, and the maximum internal friction angle of rooted-soil is 1.24 times that of plain soil. This paper provides an approach for the determination of the rooted-soil strength and a rationale for vegetation selection in ecological slope reinforcement applications.

Highlights

In highway slope engineering, reinforcement materials with a good tensile strength are usually added to the soil to improve the shear strength of the soil that forms the slope [1,2,3]
Increasing the soil shear strength simultaneously increases the stability of the slope. erefore, the study of the shearing strength of reinforced soil is very important for the stability analysis of highway slopes. e root system of a plant has a high tensile strength [4, 5] and can enhance the soil shearing strength [6,7,8]
Temgoua et al [10] studied the influence of the structure and 3D root morphology of a forest stand on slope stability using the 3D finite element method. e results show that the overall slope stability mainly depends on the depth of the root system and the additional cohesion provided by the root system

Summary

Introduction

Reinforcement materials with a good tensile strength are usually added to the soil to improve the shear strength of the soil that forms the slope [1,2,3]. E strengthening effect of plant roots on soil strength is affected by the root morphology. The root systems of different types of plants have different morphological characteristics and different mechanical effects. Van Beek et al [6] and Cammeraat et al [19] studied the effect of plant roots on the rooted-soil shearing strength using a direct shear field test. Zhang et al [23] studied the effects of the root distribution of Robinia pseudoacacia on the rooted-soil strength using a consolidated drained (CD) triaxial test. Is study aimed to study the effects of the root geometry (root diameter and individual root length) and distribution characteristics (root density and root angle) on the shearing strength of rooted-soil by controlling the root morphology of the specimen. Is study aimed to study the effects of the root geometry (root diameter and individual root length) and distribution characteristics (root density and root angle) on the shearing strength of rooted-soil by controlling the root morphology of the specimen. is study provides an approach for the determination of the rooted-soil strength and a rationale for vegetation selection in ecological slope reinforcement applications

Materials and Methods

Results

B Potential sliding surface