Wuhan University of Science and Technology, Wuhan, 430065, China.
Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China.
Sci Rep. 2021 Jul 19;11(1):14668. doi: 10.1038/s41598-021-94276-4.
The problems caused by the interaction between slopes and hydrologic environment in traffic civil engineering are very serious in the granite residual soil area of China, especially in Guangdong Province. Against the background of two heavy rainfall events occurring during a short period due to a typhoon making landfall twice or even two typhoons consecutively making landfall, laboratory model tests were carried out on the hydrological effects of the granite residual soil slope considering three vegetation types under artificial rainfall. The variation in slope surface runoff, soil moisture content and rain seepage over time was recorded during the tests. The results indicate that surface vegetation first effectively reduces the splash erosion impact of rainwater on slopes and then influences the slope hydrological effect through rainwater forms adjustment. (1) The exposed slope has weak resistance to two consecutive heavy rains, the degree of slope scouring and soil erosion damage will increase greatly during the second rainfall. (2) The multiple hindrances of the stem leaf of Zoysia japonica plays a leading role in regulating the hydrological effect of slope, the root system has little effect on the permeability and water storage capacity of slope soil, but improves the erosion resistance of it. (3) Both the stem leaf and root system of Nephrolepis cordifolia have important roles on the hydrological effect. The stem leaf can stabilize the infiltration of rainwater, and successfully inhibit the surface runoff under continuous secondary heavy rainfall. The root system significantly enhances the water storage capacity of the slope, and greatly increases the permeability of the slope soil in the second rainfall, which is totally different from that of the exposed and Zoysia japonica slopes. (4) Zoysia is a suitable vegetation species in terms of slope protection because of its comprehensive slope protection effect. Nephrolepis cordifolia should be cautiously planted as slope protection vegetation. Only on slopes with no stability issues should Nephrolepis cordifolia be considered to preserve soil and water.
在中国花岗岩残积土地区，特别是在广东省，交通土建工程中边坡与水文环境的相互作用所引发的问题十分严重。在台风连续两次登陆甚至两次登陆的背景下，两次短时间内发生两次强降雨事件，本文开展了考虑三种植被类型的人工降雨条件下花岗岩残积土路堤边坡水文效应的室内模型试验，记录了试验过程中坡面径流量、土壤含水量和雨水入渗随时间的变化。结果表明：地表植被首先能有效减轻雨水对坡面的溅蚀影响，然后通过雨水形式的调整来影响边坡的水文效应。（1）裸露边坡对两次连续强降雨的抵抗力较弱，第二次降雨时边坡冲刷和土壤侵蚀破坏程度会大大增加。（2）结缕草的茎叶多重阻碍作用在调节边坡水文效应方面起着主导作用，根系对边坡土壤渗透性和蓄水能力影响较小，但提高了边坡的抗侵蚀能力。（3）肾蕨的茎叶和根系对边坡水文效应都有重要作用。茎叶可以稳定雨水的入渗，成功抑制连续两次强降雨条件下的坡面径流。根系显著提高了边坡的蓄水能力，且在第二次降雨时大大增加了边坡土壤的渗透性，与裸露边坡和结缕草边坡完全不同。（4）结缕草在边坡防护方面是一种适宜的植被物种，因其具有综合的边坡防护效果。肾蕨作为边坡防护植被应谨慎种植，只有在边坡稳定性没有问题的情况下，才可以考虑种植肾蕨来保持水土。
