胶东铁路弃土弃渣体产流产沙特征

通过人工模拟降雨试验,研究降雨强度和坡度对胶东铁路弃土弃渣体产流产沙的影响。根据青荣铁路沿线降雨和弃土弃渣体堆积特点,设计3种雨强(20,40,60mm/h)和3个坡度(20°,30°,40°)。结果表明:(1)当降雨强度由20mm/h增加到60mm/h,产流开始时间可缩短11~20s;当坡度由20°变化到40°,产流开始时间可提前17~22s。(2)径流量、产沙率在降雨初期剧增到峰值,之后径流量逐渐趋于稳定,而产沙率波动减小后逐渐趋于稳定。(3)相同坡度条件下,雨强40 mm/h下的径流量较20 mm/h时增加37.3%~122.6%,产沙率约为20mm/h时的1.5~19.5倍;而雨强60mm/h下的径流量较40mm/h时仅增加19.1%~26.7%,产沙率仅为40mm/h时的62.5%~151.8%。(4)相同雨强条件下,坡度对径流量、产沙率的影响存在临界坡度(30°~40°),径流量、产沙率随坡度的增大先增加后减小。(5)弃土弃渣体坡度为30°时坡度对坡面侵蚀量的贡献率大于雨强贡献率;而40°时雨强贡献率明显超过坡度。研究结果可为胶东半岛区域铁路项目建设期间弃土弃渣体的水土流失监测及防治提供技术支撑。

Runoff and Sediment Yield Characteristics on Waste Soil and Slag Formed from Railway Construction in Jiaodong Peninsula Region

In order to study the effect of runoff and sediment yield on waste and slag formed from railway construction in Jiaodong Peninsula region, the artificial simulated rainfall experiments were conducted. According to the characteristics of rainfall and waste soil and slag in the study area, three different rainfall intensities with 20 mm/h, 40 mm/h, 60 mm/h and three slope gradients with 20°, 30°, 40° were designed. The results showed that both rainfall intensity and slope gradient affected initial runoff time, runoff, sediment yield, erosion amount and so on. (1) The initial runoff time decreased by 11~20 s with rainfall intensity increasing from 20 mm/h to 60 mm/h and shortened 17~22 s with the slope changing from 20° to 40°, respectively. (2) The runoff and sediment yield increased sharply to the peak during the early period of rainfall, and then the runoff gradually stabilized and the sediment yield decreased with the fluctuation and finally gradually stabilized. (3) Under the same slope gradient, the runoff in rainfall intensity with 40 mm/h increased 37.3%~122.6% compared with 20 mm/h and sediment yield was 1.5~19.5 times of that in 20 mm/h. However, the runoff in the rainfall intensity with 60 mm/h just increased 19.1%~26.7% compared with 40 mm/h, and the sediment yield was only accounting for 62.5%~151.8% of that in 40 mm/h. (4) Under the same rainfall intensity, the effect of slope gradient on runoff and sediment yield had a critical slope between 30° and 40°, and the runoff and sediment yield increased first and then decreased with the increase of slope. (5) When the slope gradient was 30°, the contribution of slope gradient to soil erosion was greater than the rainfall intensity, while the contribution of rainfall intensity obviously exceeded the slope gradient at 40°. The results can provide technical support for the soil and water loss monitoring and control during the construction process of the railway project in Jiaodong Peninsula region.