摘要
坡面侵蚀临界水流能量是反映土壤抗蚀作用强弱的重要特征值。利用人工模拟降雨试验,定量研究了在45mm/h、87 mm/h和127 mm/h降雨强度下、20°陡坡面裸地、草地和灌木地的坡面侵蚀临界水流能量。结果表明,不同植被条件下坡面输沙率随径流切应力、单位水流功率和断面比能的增大而增大,有良好的响应关系。裸地、草地和灌木地坡面侵蚀的临界径流切应力分别为0.86 N/m2、2.86 N/m2和1.65 N/m2,临界单位水流功率分别为0.0036 m/s、0.0127 m/s和0.0169 m/s,临界断面比能分别为0.074 cm、0.11 cm和0.13 cm。在具有植被条件下,只有当水流具有更大的能量时,才会引起坡面土壤侵蚀。该研究对于揭示植被调控坡面产流产沙机理,为生态修复工程建设提供科学依据具有一定的科学意义。
The critical flow energy for slope erosion is an important characteristic value measuring the erodibility of a soil.Using simulated rain of three intensities（45 mm/h,87 mm/h and 127 mm/h）,an experiment study was conducted on the critical flow energy for slope erosion under different underling conditions.The experiments were made for bare soil,grass and shrub slopes of gradient 20°.The result shows that the sediment transport rate can be linearly related to the flow energy and to the fluid shear stress under all underling conditions.Such a linear relation appears to be validated for the unit stream power and the specific energy.The critical shear stress values are respectively 0.86 N/m2,2.86 N/m2 and 1.65 N/m2 for bare soil slope,grass slope and shrub slope;while,the values for the critical unit stream power are 0.003 6 m/s,0.012 7 m/s and 0.016 9 m/s,and values of 0.074 cm,0.11 cm and 0.13 cm are found for the specific energy.The study reveals that larger critical flow energies would be required for slope erosion under vegetated conditions compared to that of bare soil.The experimental data provides a valuable asset for the mechanism study of water and sediment yields under the influence of vegetation cover,which is important to the ecological rehabilitation projects.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2011年第2期229-234,共6页
Advances in Water Science
基金
国家重点基础研究发展计划(973)资助项目(2011CB4033032007CB407201)
国家自然科学基金资助项目(41071191)
水利部黄河泥沙重点实验室基金资助项目(200905)~~
关键词
临界水流能量
植被
土壤侵蚀
坡面流
critical flow energy
vegetation cover
soil erosion
overland flow
