连续降雨下岩溶区含砾石石灰土坡面径流产沙特征

为明确砾石含量对岩溶区石灰土工程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）0.5 mm/min雨强下，土质、偏土质和偏石质坡面均未产流；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两种含砾石坡面；偏土质和偏石质坡面产流量较土质坡面增加了0.49倍和0.37倍；（2）1.0～3.0 mm/min雨强下，土质坡面侵蚀速率变化范围为0.16～5.4 g/(m2?s)，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 g/(m2?s)和0.06～0.74 g/(m2?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了2.5倍，而偏石质坡面则较其减少了0.9倍；（3）各砾石含量坡面侵蚀速率与径流率均呈极显著正相关（P＜0.01，n=76），土质坡面相关性最好，径流率对侵蚀速率具有显著影响；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幂函数、线性函数和线性函数关系；结果可为桂西北岩溶区弃渣场水土治理提供一定的科学依据。

Runoff and Sediment Yield Characteristics of Gravel-bearing Lime-Soil Slope in Karst Region under Continuous 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, runoff characteristics and erosion characteristics of meta-soil (30%) and meta-gravel (70%) lime-soil slope under incremental rainfall (0.5-1.0-2.0-2.5-3.0 mm/min) were studied by indoor simulated rainfall test method. The results showed that: (1) under 0.5 mm/min rainfall intensity, no runoff was produced on soil, partial soil and metalithic slopes; with the increase of rainfall intensity, runoff rate of each slope increased steadily and fluctuated, and runoff rate of soil slope was less than that of two gravel-bearing slopes; runoff yield of partial soil and metalithic slopes increased 0.49 and 0.37 times than that of soil slope; (2) under 1.0-3.0 mm/min rainfall intensity, runoff rate of each slope increased steadily. The change range of erosion rate of soil slope is 0.16-5.4 g/(m2?s), which shows a trend of steady-fluctuation increase. The change range of erosion rate of partial soil slope and metalithic slope is 0.16-5.4 g/(m2?s) and 0.06-0.74 g/(m2?s), respectively. The former has a large range of variation and strong fluctuation, while the latter has a small and stable range. With the increase of gravel content, the erosion amount of each slope increases first and then decreases. The trend is that the erosion amount of partial soil slope is 2.5 times higher than that of soil slope, while the erosion rate of partial rock slope is 0.9 times lower than that of soil slope; (3) the erosion rate of each gravel content slope is positively correlated with the runoff rate (P < 0.01, n = 76), and the correlation of soil slope is the best, and the runoff rate has a significant impact on the erosion rate; the erosion rate of soil, partial soil and partial stone slope is positively correlated with the runoff rate. The results can provide a scientific basis for soil and water control of abandoned slag field in karst area of Northwest Guangxi.