With the help of plant roots, slope vegetation makes the slope soil mass be-come a composite material of soil and roots, and thus enhances shear strength of the slope soil mass and stability of the slope. However, the related studies at present are still qualitative. In this paper, quantitative analysis of the interaction between roots and soil mass are made. By the analysis of the interaction between herbaceous plant roots including lateral roots of woody plants and rock and soil mass, a mechanical model of the interaction between frictional roots and soil is established, and its correctness is shown. A mechanical model of the interaction between anchorage root, namely, woody plant taproot, and soil is also established. The establishment of the models provides a useful means in quantitative analysis of the interaction between plant roots and soil, and has practical values.
The interaction between lateral root system of woody plant and soil mass is similar to the one between shrub, herbage and soil mass, and has the effect of frictional reinforcement on slope soil. It plays an important role in reinforcing soil strength in shallow slope. Therefore, slope soil mass can be considered as a composite of soil and plant roots and the soil strength and stability of shallow slope soil mass are improved. However, current researches still remain on the level of qualitatively analyzing the relation between root and soil mass. In this paper, some exploratory researches on quantitative analysis of the interaction mechanism between root and soil mass are conducted. With the study of interaction between herbage root system (lateral root system of woody plants) and soil mass, the mechanical model of interaction between frictional root and soil mass is established. The accuracy of the model is verified by field experiments of Pinus Yunnanensis. The mechanical model provides a crucial theoretical guidance to quantitatively analyzing the interaction between plant root and soil mass; it also has certain values in application.
YAN ZhiXin1’2, SONG Yun3, JIANG Ping1’2 & WANG HouYu4 1 Key Laboratory of Mechanics on Disaster and Environment in Western China (Lanzhou University), Ministry of Education, Lanzhou 730000, China
Based on guided wave theory and considering the grouted rock bolt as waveguide medium, we have constructed a three dimensional model of grouted rock bolt with the dynamics of finite difference numerical simulation software FLAC3D4.0, and simulated the propagation behavior of the guided wave in the full grouted rock bolt. The simulated waveform and wave velocity matched well with the experimental results. We have made a more in-depth and comprehensive study of the wave velocity, wave component and attenuation characteristics of the guided wave propagating in rock bolt, and found some new characteristics and phenomena. In addition, some phenomena that haven’t been explained in the previous researches have also been discussed in this paper. The result showed that when guided wave propagates in grouted rock bolt, after the body wave decays, there is still the interface wave-Stoneley wave that does not decay in the axial direction of the bolt. The findings can provide some reference for rock bolt testing and the selection of the optimal excitation wave of testing.
YAN ZhiXinCAI HanChengWANG QunMinCAO XiaoHongZHANG LiuPing
