人工降雨作用下边坡植被水文效应模型试验研究

发布时间：2018-01-02 13:20

本文关键词：人工降雨作用下边坡植被水文效应模型试验研究　出处：《海南大学》2015年硕士论文　论文类型：学位论文

【摘要】：海南岛森林资源丰富,植被覆盖率高,但随着近几年岛内经济的发展,人类工程活动和山区开荒种植经济作物对山区边坡植被造成了不同程度的破坏,在台风天气强降雨作用下,植被破坏的区域出现了大量小规模的边坡失稳现象。这些小规模的边坡破坏形态多为降雨作用下的坡面冲蚀和浅层位移,造成的人身伤害和财产损失虽然不大,但给旅游交通和观光带来诸多不便。因此本文从边坡植被生态护坡的角度出发,研究边坡植被在降雨作用下的水文效应,探索植被护坡的作用机理。本文建立了人工降雨边坡试验模型,试验所用土料为海口美兰区粉土,试验设置裸土、肾蕨、细叶结缕草三种边坡模型。试验模型的监测观测系统能够收集测量地表径流,实时采集坡体内部土壤含水率,监测雨水渗透量,观测坡体外观形态变化。首先对模型所用粉土进行了室内试验研究。包括物理性质指标的测定和饱和度对非饱和粉土抗剪强度指标的影响。试验结果显示非饱和粉土的抗剪强度在饱和度50%左右出现峰值,高于50%时随着饱和度的升高而减小,低于50%时随着饱和度的降低而减小。由于粉土中粉粒的特殊性质,粉土在自然晾干脱水的过程中会出现很高的表观粘聚力。通过两次人工模拟降雨,对比三种不同植被的边坡模型。得知边坡植被主要通过拦截雨水形成地表径流,改变雨水渗透路径,影响边坡土体的渗透性等水文效应来保护坡体。边坡植被植物特性不同,所发挥的生态护坡作用也各有所长。细叶结缕草护坡作用主要通过拦截雨水形成地表径流、改变雨水渗透路径；肾蕨护坡作用主要通过改变雨水渗透路径、影响边坡土体的渗透性。试验所设置的裸土边坡在两次不同强度的降雨过程中,遭受的破坏主要是冲击变形、坡面溅蚀和冲刷侵蚀。综合分析可知,边坡植被在降雨过程中能够通过自身的水文效应避免雨水的直接冲刷和减缓表层土体滑动来发挥护坡作用。且边坡植被的存在会改善坡体内含水率的变化从而影响边坡土体的抗剪强度提高边坡的稳定性。
[Abstract]:Hainan Island is rich in forest resources and has high vegetation coverage. However, with the development of the island economy in recent years, human engineering activities and the cultivation of cash crops in mountainous areas have caused varying degrees of damage to the slope vegetation. Under the action of typhoon and heavy rainfall, a large number of small scale slope instability phenomenon appeared in the area of vegetation destruction. Most of these small slope failure patterns are slope erosion and shallow displacement under the action of rainfall. Although the personal injury and property loss caused by the slope is small, it brings much inconvenience to tourism and tourism. Therefore, this paper studies the hydrological effect of slope vegetation under rainfall from the angle of slope vegetation ecological slope protection. To explore the mechanism of vegetation slope protection. The experiment model of artificial rainfall slope is established in this paper. The soil material used in the experiment is silt in Meilan district of Haikou. The bare soil and the kidney fern are set up in the experiment. The monitoring and observation system of the experimental model can collect and measure the surface runoff, collect the soil moisture content in the slope in real time, monitor the permeability of Rain Water, and observe the appearance changes of the slope body. First of all, the laboratory test of silt used in the model was carried out, including the measurement of physical properties and the effect of saturation on the shear strength of unsaturated silt. The test results show that the shear strength of unsaturated silt is saturated. The peak value of degree is about 50%. When the saturation is higher than 50, it decreases with the increase of saturation, and decreases with the decrease of saturation when lower than 50, because of the special properties of silt particles. High apparent cohesion occurs in the process of natural drying and dehydration of silt. The slope models of three different vegetation were compared by two artificial rainfall simulation. The results showed that the slope vegetation mainly formed surface runoff by intercepting Rain Water and changed Rain Water infiltration path. Hydrological effects such as affecting the permeability of slope soil are used to protect slope body. The plant characteristics of slope vegetation are different. The ecological slope protection has its own advantages. The slope protection of Zoysia tenuifolia mainly forms surface runoff by intercepting Rain Water and changes Rain Water infiltration path. The slope protection of kidney fern affected the permeability of slope soil by changing Rain Water infiltration path. The failure of bare soil slope was mainly caused by impact deformation during two rainfall periods with different intensity. Sloping erosion and erosion. Comprehensive analysis shows that. In the process of rainfall, slope vegetation can avoid Rain Water's direct erosion and slow down the sliding of surface soil through its own hydrological effect, and the existence of slope vegetation will improve the change of water content in slope. The stability of the slope is improved by the shear strength of the soil.
【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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