Promoting effect of vegetation on the landslide induced by typhoon rainstorm
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摘要: 植被在世界各地被广泛用于防止滑坡,但在我国东南沿海的台风季节,植被覆盖较好的地区受台风暴雨诱发常有大量滑坡发生。为了研究台风暴雨条件下植被对滑坡发育的促进作用,通过风洞物理模拟实验研究了风荷载和植被摇曳对滑坡稳定性的影响。结果表明: 台风通过植被对边坡施加的荷载不容忽视,在超强台风条件下(风速≥17 m/s),风荷载可使潜在滑坡体的下滑力增加10%以上; 由于台风的风荷载,植被会通过根部对土壤施加强大的扭矩,导致土壤出现裂缝,这些裂缝为雨水渗透提供了快速通道,土壤的渗透系数会增加10倍以上。因此在东南沿海地区的台风季节,应注意植被、特别是高大乔木对滑坡稳定性的不利影响。Abstract: Vegetation is widely used for preventing landslides around the world. However, an amount of rainstorm-induced landslides occurred frequently on vegetation-covered slopes during the typhoon season in the coast of Southeastern China. In order to investigate the effect of vegetation on the development of landslide under the condition of typhoon and rainstorm, the authors in this paper simulated the effect of wind load and vegetation swaying on stability of landslide through wind tunnel physical simulation tests. The results show that the load exerts on the slope by typhoon through vegetation shouldn‘t be ignored. The wind load can increase the sliding force by more than 10% under super typhoon (with wind speed of 17 m/s). Meanwhile, the strong torque was loaded the on soil via the vegetation root, resulting in cracks in the soil. These cracks provide fast paths for rainwater infiltration, and the permeability coefficient of soil increased more than ten times later. Therefore, special attention should be paid to the potential implications of vegetation in the future, especially the high trees, which have disadvantages on landslides during typhoons.
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Key words:
- typhoon and rainstorm /
- landslide /
- vegetation /
- southeast coastal area
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