National Program on Key Basic Research Project of China(No.YS2016YFSF030019) and National Natural Science Foundation of China(Nos.40771127,41761062)
为明确砾石含量对风沙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，研究了不同降雨强度（1.0、1.5、2.0和2.5 mm?min-1）条件下不同砾石质量含量（10%、20%、30%）的风沙土堆积体坡面径流特性及侵蚀产沙规律。结果表明：（1）1.0、1.5、2.5 mm?min-1雨强下，10%砾石含量坡面径流率较土质坡面减少5.03%～39.99%，而20%、30%砾石含量坡面径流率则分别增加7.48%～74.56%、19.51%～84.31%；各砾石含量坡面径流率均与雨强呈显著递增的指数函数关系；（2）土质和含砾石坡面径流型态基本以层流为主；土质坡面径流流态多为急流，而含砾石坡面径流则以缓流为主；各雨强条件下，10%、20%、30%砾石含量坡面径流阻力系数较对照分别增加24.07%～114.10%、51.84%～141.57%、89.04%～288.16%；（3）1.0、1.5 mm?min-1雨强下土质和10%砾石含量坡面侵蚀速率随降雨历时呈减小—稳定—增大趋势，2.0、2.5 mm?min-1雨强下，则呈波动式逐渐增大趋势；4种雨强下，20%、30%砾石含量坡面侵蚀速率呈缓慢、平稳增加趋势；（4）雨强为1.0 mm?min-1时土质坡面侵蚀量最小，雨强≥1.5 mm?min-1时，含砾石坡面侵蚀量较土质分别减少41.08%～63.27%、22.80%～67.80%、28.89%～68.50%；（5）侵蚀量与径流率、雷诺数、弗汝德数均呈显著正相关关系，与阻力系数则呈显著负相关关系；结果可为陕北风沙土区生产建设项目工程堆积体水土流失量估算模型的建立提供科学参考。
【Objective】During the production and construction processes in North Shaanxi, large stacks of soils formed, triggering serious soil and water losses. The existence of gravels in the stack is an important factor affecting the soil erosion in characteristic. Therefore, this study was oriented to explore impact of gravel concentration on runoff and sediment yielding processes on slopes of the gravel-containing aeolian sand stacks. 【Method】In this study an indoor simulated rainfall experiment was carried out on stacks. The experiment was designed to have three levels of gravel concentration (10%, 20% and 30%), four levels of rainfall intensity (1.0 mm?min-1, 1.5 mm?min-1, 2.0 mm?min-1 and 2.5 mm?min-1) and one pure soil slope (containing zero gravel) as control. The experimental plots were 5 m × 1 m × 0.5 m each in size and laid on slopes 25 ° in gradient. The nozzles of the rainfall simulator were 18 m high above the ground, providing artificial rainfall over 80% in uniformity. Rainfall intensity was determined before the start of each artificial rainfall event to ensure the artificial rainfalls < 5% higher or lower than the designed one. During the experiment, flow velocity of runoff on the slope was measured with the dyeing method, flow width measured with a steel ruler, duration of sediment pooling recorded with a stopwatch, and mass of the sample determined with an electronic scale. 【Result】Results show: (1) Under artificial rainfalls, 1.0, 1.5, or 2.5 mm?min-1 in intensity, runoff rates were 5.03% ~ 39.99% lower on the slopes 10% in gravel concentration than on CK, but 7.48% ~ 74.56% and 19.51% ~ 84.31% higher on the slopes 20% and 30% in gravel concentration, respectively; runoff rates on all the slopes increased with rising rainfall intensity, displaying an exponential function relationship; (2) Runoffs on all the slopes formed laminar flows; on CK runoffs rushed a bit, while on the slopes containing gravels they flew slowly; Under rainfalls varying in intensity, drag coefficients of runoffs on slopes, 10%, 20% and 30% in gravel concentration increased by 24.07% ~ 114.10%, 51.84% ~ 141.57% and 89.04% ~ 288.16%, respectively; (3) Under rainfalls 1.0 and 1.5 mm?min-1 in intensity, soil erosion rate on CK and the slopes 10% in gravel concentration displayed a variation trend with rainfall going on, i.e. decreasing – stabilizing – increasing, and under rainfalls 2.0 and 2.5 mm?min-1 in intensity, it fluctuated more vigorously; Under rainfalls regardless of intensity, soil erosion rate on the slopes 20% and 30% in gravel concentration decreased slowly and then increased steadily; (4) Under rainfalls 1.0 mm ?min-1 in intensity, CK was the lowest in soil erosion rate and under rainfalls ≥ 1.5 mm ?min-1, soil erosion rate decreased by 41.08% ~ 63.27%, 22.80% ~ 67.80%, 28.89% ~ 68.50% on the slopes 10%, 20% and 30% in gravel concentration, respectively; (5) Soil erosion rate was significantly and positively related to runoff rate, Reynolds number, and Freud number, but negatively to drag coefficient. 【Conclusion】All the findings in this study will provide a theoretical basis for establishment of a model for predicting water and soil losses of engineering stacks of aeolian-sand soil in North Shaanxi.
赵 满,王文龙,郭明明,康宏亮,白 芸,王文鑫,陈卓鑫,杨 波.含砾石风沙土堆积体坡面径流产沙特征[J].土壤学报,2019,56(4):847-859. DOI:10.11766/trxb201808130223 ZHAO Man, WANG Wenlong, GUO Mingming, KANG Hongliang, BAI Yun, WANG Wenxin, CHEN Zhuoxin, YANG Bo. Runoff and Sediment Yielding Characteristics of Slopes of Stacks of Gravels-Containing Aeolian Sandy Soil[J]. Acta Pedologica Sinica,2019,56(4):847-859.复制