2种扰动土壤工程堆积体坡面泥沙运移特征比对研究

Comparative Study of Sediment Particle Transport on Slopes of Two Disturbed Soil Engineering Accumulations

为探究不同土壤类型对工程堆积体坡面侵蚀泥沙搬运的影响,选取构筑堆积体的2种扰动土壤,设定4个放水梯度(8,12,16,20 L/min)在32°条件下进行野外冲刷试验。结果表明:2种坡面产流产沙率均随冲刷延时呈"多峰多谷"变化;较扰动风沙土堆积体,扰动红壤堆积体产流产沙率均随流量增加上升速率较缓;流量20 L/min时,重力在扰动风沙土堆积体坡面侵蚀中发挥主导作用;各放水梯度下2种堆积体坡面累积产沙量与累积径流量均呈极显著线性关系(P<0.01,R^2>0.99);随流量增大,搬运泥沙颗粒组成均接近原状土,扰动风沙土坡面径流搬运泥沙颗粒以砂粒为主(> 60%),扰动红壤坡面径流搬运泥沙颗粒各组分比例相对均匀(各组分含量为24%~41%)。该研究结果可为不同土壤类型堆积体坡面水土流失防控措施科学配置提供理论依据。

In order to study the effects of different soils on sediments particle transport on slopes of engineering accumulation, a field scouring experiment was carried out under two kinds of disturbed soil, red and aeolian sandy soil, four flow gradients 8, 12, 16 and 20 L/min, and under the condition of 32°. The results showed that:(1) The runoff and sediment yield of the two accumulation slopes showed a "multi-peak and multi-valley" change process with time.(2) Compared with the disturbed aeolian sandy soil accumulation, the rate of sediment yield on the slope of disturbed red soil accumulation increased slowly with the increasing discharge flow rates. When the discharge flow rate was 20 L/min, the gravity factor played a leading role in the slope erosion of aeolian sandy soil accumulation.(3) The cumulative sediment yield of the two engineering accumulations was significantly correlated with the cumulative runoff, which could be described by linear function(P < 0.01, R^2 > 0.99).(4) With the increase of discharge rates, the proportion of sediment particles transported on the slope of the accumulation was close to the original soil. The main erosion sediment particles of the aeolian sandy soil were sand grains(> 60%), the proportion of transportation of red soil particles was relatively uniform(the sediment transport contents ranged from 24% to 41% for each particle size). The difference in slope erosion of different accumulations was closely related to soil texture. These results could provide theoretical basis for the prevention and control measures for soil erosion on slopes of different soil types.