矿区3种弃土弃渣体侵蚀及水动力学差异研究

Differences in Erosion and Hydrodynamic Characteristics of Three Kinds of Residues in Mining Area

人为因素影响使得矿区扰动地表范围广,形成的弃土弃渣物质组成复杂,且堆积坡度较大,在降雨作用下容易产生严重水土流失。在野外调查基础上,通过选取、修筑径流小区并建立野外人工模拟降雨场,研究弃土体、沙多石少弃渣体和沙少石多弃渣体3种下垫面的侵蚀及水动力特征的差异性。结果表明:(1)弃土弃渣体平均径流率随雨强增大1.5~3.0倍,递增幅度是33.7%~276.2%。(2)沙多石少弃渣体的平均流速较弃土体及沙少石多弃渣体大,随雨强增大,3种弃土弃渣体的平均流速递增13.6%~43.3%;同雨强下,沙多石少弃渣体平均侵蚀速率分别是弃土体和沙少石多弃渣体的1.8倍和11.2倍。(3)弃土弃渣体次降雨下的平均雷诺数以过渡流为主,水流呈缓流。平均径流率与平均水流功率、水流剪切力分别可用线性函数表示,决定系数>0.8;弃土体及沙少石多弃渣体平均侵蚀速率与平均水流功率、水流剪切力分别可用线性函数表示,决定系数>0.9,而沙多石少弃渣体呈幂函数关系,决定系数在0.5左右。

Affected by man-made factors,ground surface in coal mine area is disturbed in a wide range,with complex waste soils and residues accumulating into steep slopes,resulting in heavy soil and water loss under rainfall action.On the basis of field investigations,runoff plot and outdoor artificial rainfall field were selected and constructed to study the differences of erosion and hydrodynamic characteristics among three underlying surfaces,namely,waste soil,coal mine residue with more sand and less stone,and residue with less sand and more stone.Results showed that 1） the average runoff rate of residues increased in a range from 33.7% to 276.2% with rainfall intensity increasing by 1.5 times to 3.0 times; the average runoff velocity of waste soil and residues increased by 13.6%-43.3%as rainfall intensified,and the average runoff velocity of residue with more sand and less stone was larger than the other two; under the same rainfall intensity,the average erosion rate of residue with more sand and less stone was1.8 times and 11.2 times that of the waste soil and the residue with less sand and more stone,respectively; 3） the average Reynolds number revealed waste soil and residue as transition flow in slow motion; 4） the relations between average runoff rate and average stream power and average shear stress,respectively,can be expressed by linear function,with the coefficient of determination greater than 0.8; the relations between erosion rate and average stream power and average shear stress of waste soil and residue with less sand and more stone can be expressed by linear function,with the coefficient of determination greater than 0.9; while a power function for residue with more sand and less stone with the coefficient of determination about 0.5.