渭北旱塬垃圾堆积降雨侵蚀试验研究

[目的]研究渭北旱塬垃圾堆积降雨侵蚀过程及机理,为渭北旱塬垃圾堆积降雨侵蚀防治提供科学依据。[方法]基于人工模拟降雨试验,设计了2个降雨强度(1.2和2.0mm/min)以及2个垃圾堆积类型(即垃圾堆积成斜坡,无侵蚀发生地表上的垃圾堆),进行2个垃圾堆积类型和裸露的撂荒坡降雨侵蚀过程的对比研究。[结果]当降雨强度I=1.2mm/min,垃圾堆积成斜坡的侵蚀产沙总量为117.94kg,撂荒坡的侵蚀产沙量为10.86kg,垃圾堆积成斜坡比撂荒坡的侵蚀产沙总量为107.08kg;当降雨强度I=2.0mm/min,垃圾堆积成斜坡比撂荒坡的侵蚀产沙总量多出225.72kg,而倾倒在无侵蚀发生地表上的垃圾堆积侵蚀产沙量相对较少;对垃圾堆积坡面径流的侵蚀能量(E)及侵蚀能量消耗(E启动泥沙、E搬运泥沙)、含沙水流作用于底床上的拖曳力(F)分析得出,垃圾堆积与下垫面形成了缝隙或软弱面,从而导致坡面径流,降低了启动松散垃圾堆积泥沙颗粒所消耗的能量,坡面径流的侵蚀能量(E)主要消耗在搬运输移垃圾堆积颗粒。[结论]含有垃圾颗粒物质水流将维持较高流速,含有垃圾颗粒物质水流因其产生较强的拖曳力加剧了细沟侵蚀。

Rainfall-simulated Erosion and Sediment Yield of Rubbish-dump in Dry Upland of Northern Weihe River

[Objective] The process and mechanism of erosion and sediment yield of rubbish-dump in dry upland of Northern Weihe river were illustrated to provide scientific bases for the prevention and control of rainfall erosion on rubbish-dump. [Methods] Experiments of erosion and sediment yield were conducted on rubbish dumps with two slope gradients(steep slope and tiled dump) and rainfall simulation intensities(1,2 and 2.0 mm/m). [Results] When rainfall intensity I was at 1.2 mm/min, the sediment yield on the steep slope dump was 117.94 kg, an increment of 107.08 kg was observed in comparison with the one on tiled dump of 10.86 kg. When rainfall intensity was at 2.0 mm/m, the sediment yield on steep slope dump got an increment of 225.72 kg in contrast to the one on tiled dump. The energy of erosion(E), including the consume energy(E_{startup sediment},E_{move sediment}), and the dragging resistance at bottom plate(F) were elucidated: The existed space and soft layer between rubbish-dump and the original landform below it can reduce the E start up sediment, the energy of erosion(E) was mainly consumed by moving sediment. [Conclusion] The current with the sediment yield will keep a high speed and a strong dragging force from bottom plate(F). As a result, rill erosion was strengthened.