【摘要】 黄土高原沟壑纵横,塬面水流在入沟过程中,不断冲刷沟头,导致沟底下切,沟壁坍塌,形成溯源侵蚀。为防止从沟头跌落的水流对沟底冲刷,减缓沟头侵蚀发展,保护塬面,采用柔性防护措施消减水流动能。试验通过覆麦草和土工布模拟柔性防护措施,研究柔性防护措施的消能机理。试验以裸土为对照,测定在高水头冲刷下,不同防护措施的冲刷坑深度、坑径、坑面积及坑容积,定量分析了柔性防护措施的作用效果。结果表明:随着覆麦草量的增加,冲刷坑深度呈线性递减、容积呈指数递减;而加覆土工布,能显著提升防护效果;在4.93 m试验水头冲刷3 min的条件下,覆2 400 g/m~2麦草和1层土工布能够完全保护土面不被冲刷。柔性防护措施具有良好的消减水流动能的作用,对防止沟床下切,有效保护塬面,防治沟头侵蚀效果显著。更多还原

【Abstract】 The gully is interlaced on Loess Plateau and the water flow in the gully is continuously scouring the gully head, which can cause the bottom of the gully to cut and the gully wall to collapse, causing headward erosion. The flexible protective measures can be used to reduce water flow energy in order to prevent the water flow falling from the gully head from scouring the gully bottom and slowing the development of the gully erosion, and to protect the surface. The wheat straw and geotextile were used to cover the soil surface and examine the energy dissipation mechanism of these protective measures compared with the bare soil through indoor simulation experiment. The depth, diameter, area and volume of the scouring pit which caused by high water head and under different protective measures were measured, and the effect of flexible protective measures were analyzed quantitatively. The results showed that the depth of the scouring pit decreased linearly and the volume decreased exponentially with the increase of the amount of wheat straw, and the addition of geotextile could significantly improve the protective effect; under 4.93 m water head for 3 minutes washing, covering 2 400 g/m~2 of wheat straw and a layer of geotextile could completely protect the soil surface from being washed away. The flexible protective measures have a good effect to reduce the water flow energy, and are effective in preventing the undercut of the gully bed, effectively protecting the plateau surface, preventing the erosion of the gully head.更多还原