摘要
煤炭开采过程形成的工程堆积体可导致严重水土流失。该文以重庆市煤矿工程堆积体为研究对象,该文采用土工试验方法和野外实地放水冲刷试验研究了煤矿工程堆积体边坡径流侵蚀特征及其临界水动力条件。结果表明:1)随着径流侵蚀冲刷过程进行,工程堆积体边坡的径流流速、径流剪切力和径流功率均呈现出程度不一波动现象,其变化范围分别为0.187~0.526 m/s、24.336~126.542 Pa、2.763~46.861 N/(m·s),而阻力系数在2.236~19.337之间波动变化。2)除10 L/min放水条件,工程堆积体边坡产流率、产沙率随径流冲刷过程呈先增加、后稳定变化趋势;在不同放水条件(10~30 L/min)下,边坡产流率依次趋于0.5、3.0、3.8、6.3和9.0 L/min,而产沙率在0~27.51 kg/min之间变化,土壤剥蚀率在9.570~4616.064 g/(m2·min)。3)不同坡度工程堆积体边坡临界径流剪切力及径流功率存在较大差异,面蚀阶段临界径流剪切力和临界径流功率以30°堆积体最小,分别为23.95 Pa和1.76 N/(m·s);而细沟侵蚀阶段以25°堆积体临界径流剪切力最小,以40°堆积体临界径流功率最小;土壤侵蚀速率与径流剪切力、径流功率之间具有显著线性关系。4)在放水条件下(10~30 L/min),工程堆积体径流侵蚀临界坡度分别为34.8°、35°、33.7°、34°、35.2°。研究结果可为煤矿工程堆积体水土流失量预测、水土保持生态修复措施布置提供技术参数和依据。
Various engineering accumulations, caused by all man-made activities during mining process, have resulted in serious artificial soil and water loss in the coal mine area because of great difference in material composition, slope structure and runoff and sediment characteristics from original landforms, which would make great potential risk for the mining safety production and the surrounding areas. Recently, researches begin to focus on artificial soil and water loss in project areas, however, mechanism of runoff erosion on engineering accumulation slopes is still unclear, especially hydrodynamic characteristics in the process of runoff erosion needs further study. Taking typical coal mine engineering accumulation as example, soil test method and field scouring experiment were conducted to study the runoff erosion characteristics and critical hydrodynamic conditions of engineering accumulation slopes in the coal mine area. In this paper, some physical properties, hydraulic properties and runoff erosion process on slopes of engineering accumulations with different producing sources were all comparatively studied. Field scouring experiments were carried out from July to August 2013 at the Soil Erosion Experiment Site for production and construction projects in Southwest University, Chongqing. The field scouring experiments contained 5 flow discharges(i.e. 10, 15, 20, 25 and 30 L/min) and 4 slope gradients(i.e. 25°, 30°, 35° and 40°). The paper mainly studied the hydrodynamic characteristics of engineering accumulation slopes in order to reveal the characteristics of runoff and sediment yield and soil erosion rate, and to analyze the relationship between soil erosion and critical hydrodynamic conditions and the critical slope gradient under different flow discharges. The results indicated that: 1) During runoff erosion process, both flow velocity, flow shear stress and runoff power of engineering accumulation slopes exhibited different degrees of fluctuation, showing a range of 0.187-0.526 m/s, 24.336-126.542 Pa and 2.763-46.861 N/(m·s), respectively, however, resistance coefficient existed a fluctuation from weak to strong in the range of 2.236-19.337. 2) Both runoff yield rate and sediment production rate of engineering accumulation slopes exhibited a trend of first increase and then stability during runoff erosion process except for the 10 L/min flow discharge. The runoff yield rate tended to 0.5, 3.0, 3.8, 6.3 and 9.0 L/min, respectively, under different flow discharges(10 to 30 L/min), however the sediment yiled rate varied between 0 and 27.51 kg/min and the soil detachment rate changed between 9.570 and 4616.064 g/(m^2·min). 3) There were great difference in critical flow shear stress and critical runoff power among engineering accumulation slopes with different slope gradients. At sheet erosion stage, both the critical flow shear stress and critical runoff power of 30° engineering accumulation were the minimum, whose values were 23.95 Pa and 1.76 N/(m·s), respectively; at rill erosion stage, however, the critical flow shear stress of 25° engineering accumulation was the minimum and the critical runoff power of 40° engineering accumulation was the least; and the soil erosion rate had a significant linear relationship with the flow shear stress and runoff power. 4) When flow discharge was 10-30 L/min, the critical slope gradients of engineering accumulations were 34.8°, 35°, 33.7°, 34° and 35.2°, respectively. These results not only could provide essential technical-parameters for predicting soil and water loss caused by mining production, but also would help to arrange some vegetation measures for soil and water ecological restoration of these engineering accumulations.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2016年第18期153-161,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
重庆市水利局科技项目“生产建设项目弃土弃渣水土流失规律研究”(2011)
“重庆市生产建设项目水土流失危害研究”(2012)
“重庆市水力侵蚀监测点背景侵蚀环境调查”(2016)
关键词
径流
侵蚀
水动力学
临界条件
工程堆积体
煤矿工程
runoff
erosion
hydrodynamics
critical condition
engineering accumulation
coal mine project