# Experimental Study of Influence of Plant Roots on Dynamic Characteristics of Clay
## 1 Introduction  
In recent decades, rapid development has been witnessed in critical infrastructure sectors such as highways, railways, and bridges in China. However, as a consequence, a significant number of exposed engineering slopes have been formed, making them highly susceptible to various geological hazards. As a response to this issue, vegetation-based ecological protection has emerged as an essential approach for mitigating engineering slope disasters and preserving the ecological environment, thus becoming a current research focus within the field of geotechnical engineering [1, 2, 3]. Vegetation-based ecological slopes are defined as measures adopted on slope surfaces, including grass planting and tree plantation, aiming to stabilize and protect the soil on the surface and prevent the occurrence of natural disasters such as soil erosion [4] and landslides [5]. Additionally, environmental beautification and the promotion of ecosystem restoration are also achieved through these measures [6]. The soil damping ratio, as a critical indicator of the energy dissipation capacity of soil under dynamic loading, holds extensive research value in the field of geotechnicalengineering. Particularly in slope protection engineering, the soil damping ratio directly affects the stability and response characteristics of slopes under dynamic loads such as earthquakes and vibrations. In the 1960s and 1970s, extensive research was conducted on the damping ratio and shear modulus of soils by scholars such as [PERSON] [7] and [PERSON] et al. [8; 9]. It was observed that the damping ratio of soils tends to increase with the increase in shear strain amplitude. The experimental results of the dynamic stress-strain relationship of soil were analyzed and summarized by [PERSON] et al. [10]. It was recommended to use the plasticity index to describe the empirical curve of the relationship between damping ratio and shear strain. However, it has been found that using a single parameter (such as plasticity index) to describe the damping ratio attenuation curve does not match the actual working load conditions (soil usually bears multiple complex dynamic loads, such as earthquakes, mechanical vibrations, and traffic loads). The dynamic shear modulus and damping characteristics of red sandstone [11; 12] and tailings [13; 14] were investigated by researchers, yielding valuable research findings. [PERSON] et al. [15] proposed empirical G/G max and D curves for the dynamic properties of cohesive core materials by analyzing the shear modulus and damping ratio curves of dam cores. [PERSON] et al. [16] conducted experimental research on the dynamic properties of fiber-modified soil, revealing that a fiber content of 0.2% resulted in minimal damage and maximum dynamic strength and elastic modulus for the modified soil samples. [PERSON] et al. [17] conducted a dynamic analysis of gravel based on shear modulus and damping ratio, deriving a fitted relationship between optimal damping ratio and shear modulus. [PERSON] et al. [18] performed large-scale dynamic triaxial tests on rice husk ash-modified soil, analyzing the effects of the rice husk ash content, dynamic stress amplitude, and reinforcement method on the axial cumulative deformation, dynamic stress-strain curve, and dynamic elastic modulus. [PERSON] et al. [19] investigated the improvement in the dynamic performance of loess in the Xining area before and after reinforcement using bidirectional geogrids. The mechanism by which grass roots reinforce soil primarily involves two aspects: directly enhancing soil structure through physical interaction and regulating soil moisture and matric suction, while indirectly improving soil shear strength. Their combined effect significantly increases soil strength and stability. Most studies consider the tensile strength of roots as a direct measure of apparent root cohesion in slope soils [20]. Regarding the dynamic characteristics of root-soil composites, [PERSON] et al.