连续模拟降雨下岩溶区含砾石堆积体坡面径流产沙特征

为明确砾石含量对岩溶区石灰土质堆积体坡面径流产沙特征的影响,以土质坡面为对照,采用室内模拟降雨试验方法,研究了递增型降雨(0.5,1.0,2.0,2.5,3.0 mm/min)条件下偏土质(砾石含量30%)和偏石质(砾石含量70%)石灰土坡面的径流特性及侵蚀特征。结果表明:(1)随雨强增大,各坡面径流率呈稳定增长—波动的变化趋势,且土质坡面径流率整体小于2种含砾石坡面;偏土质、偏石质坡面累计产流量较土质坡面增加了0.49,0.37倍;(2)1.0~3.0 mm/min雨强下,土质坡面侵蚀速率在0.16~5.4 g/(m^2·s)范围内波动,整体呈稳定—波动增加的变化趋势;偏土质和偏石质坡面分别为0.16~5.4,0.06~0.74 g/(m^2·s),前者侵蚀速率变化范围大且波动剧烈,后者变化范围小且稳定;随砾石含量的增加,各坡面累计侵蚀量呈先增后减的变化趋势,偏土质坡面侵蚀量较土质坡面增加2.5倍,偏石质坡面较其减少了0.9倍;(3)土质、偏土质和偏石质坡面的侵蚀速率与径流率分别呈极显著正相关幂函数、线性函数和线性函数关系。研究结果可为桂西北岩溶区弃渣场水土流失治理提供一定的科学依据。

Characteristics Sediment Yield and Runoff on the Slope Surface of Gravel Accumulation in Karst Area Under Continuous Simulated Rainfall

In order to clarify the influence of gravel content on runoff and sediment yield characteristics of lime-soil engineering deposit slope in Karst area, the runoff characteristics and erosion characteristics of lime-soil slope with meta-soil (30%) and meta-gravel (70%) under incremental rainfall (0.5, 1.0, 2.0, 2.5 and 3.0 mm/min) were studied by indoor simulated rainfall test method. The results showed that: (1) With the increasing of rainfall intensity, the runoff rate of each slope showed a stable growth fluctuation trend, and the runoff rate of soil slope was less than that of two kinds of gravel slope, and the runoff yield of partial soil and partial stone slope was 0.49 times and 0.37 times higher than that of soil slope. (2) Under the rainfall intensity of 1.0~3.0 mm/min, runoff rate of each slope fluctuated in the range of 0.16~5.4 g/(m²·s), which showed a trend of steady-fluctuation increase. The change range of erosion rate of partial soil slope and partial stone slope was 0.16~5.4 g/(m²·s) and 0.06~0.74 g/(m²·s), respectively. The former had a large range of variation and strong fluctuation, while the latter had a small and stable range. With the increasing of gravel content, the erosion amount of each slope increased first and then decreased. The erosion amount of partial soil slope was 2.5 times higher than that of soil slope, while the erosion rate of partial stone slope was 0.9 times lower than that of soil slope.(3) The erosion rate of soil, partial soil and partial stone slope was positively correlated with the runoff rate, which was power function, linear function and linear function, respectively. The results could provide a scientific basis for soil and water control of abandoned slag field in Karst area of Northwest Guangxi.