神府煤田弃土弃渣堆积体径流侵蚀特征

Runoff Erosion Characteristics on Waste Overburden and Waste Slag Deposit in Shenfu Coalfield

为研究神府煤田弃土弃渣堆积体径流产沙规律,采用野外模拟降雨试验的方法研究了不同降雨强度条件下偏石质弃渣体(Ⅰ)、偏土质弃渣体(Ⅱ)及弃土体(Ⅲ)径流侵蚀特征。结果表明:(1)Ⅰ和Ⅱ弃渣体砾石含量分别为69.33%和45.06%,颗粒级配良好,而弃土体颗粒级配不良,以沙粒为主(90.31%);(2)雨强为1.0 mm/min时Ⅰ弃渣体和弃土体径流为层流,其余条件下各堆积体径流均为紊流,各堆积体坡面径流率、雷诺数和单位径流功率均与雨强成显著递增的线性或幂函数关系;(3)Ⅰ和Ⅱ弃渣体侵蚀速率随降雨时间以峰谷交替式的趋势下降至稳定,弃土体则呈增大—减小—稳定的变化趋势,Ⅱ弃渣体侵蚀波动性最强,侵蚀速率最大,Ⅰ弃渣体和弃土体侵蚀速率与雨强和径流率均成显著的指数关系;(4)Ⅰ、Ⅱ和Ⅲ堆积体土壤可蚀性分别为40.713、379.77、93.355 g/m^3,发生侵蚀的临界单位径流功率分别为4.61×10^(-3)、6.26×10^(-3)、5.94×10^(-3)m/s。

In order to study runoff and sediment yielding law of waste overburden and waste slag in Shenfu Coalfield, the field artificially sim-ulated rainfall experiments were conducted to study the characteristics of runoff and sediment yielding of waste slag with more gravel （ Ⅰ ）, waste slag with more soil （ n ）,and waste overburden （ n ） under different rainfall intensities. The results show that： a ） the gravels of the main components of I and n account for 69.33% and 45.06% of total particles,respectively,and their particle size distributions are good. The sand content of waste overburden is 90.31%,and its particle size distribution is uneven; b ） the flow regime of Ⅰ and Ⅱ is laminar flow （Re〈500 ） under 1.0 mm/min rainfall intensity and the flow regime is turbulent flow for other all tests. The runoff rate,Reynolds number, and unit stream power of Ⅰ and H increase with rainfall intensity increasing. The relationships between runoff rate,Reynolds number and u-nit stream power and rainfall intensity can be described by power or linear function; c ） the erosion processes of waste slag Ⅰ and n present a multi-peaks and multi-valleys trend and tend to a stable status finally, while the waste overburden presents a rise-decline-stable trend with a single peak value in erosion rate. The erosion rate on the slope of slag n is the maximum and its volatility is the most violent. The erosion rates of Ⅰ and H are significantly related to rainfall intensity and runoff rate with exponential function; d ） the soil erodibilities of Ⅰ, n and H are 40.713 g/m3,379.77 g/m3 and 93.355 g/m3,respectively. The critical unit stream power initiating soil erosions of Ⅰ ,Ⅱ and Ⅲ are 4.61×10-3m/s,6.26×10-3 m/s,5 .9 4 × 1 0 -3 m/ s,respectively.