基于REE示踪法的工程堆积体坡面泥沙来源研究

A Study on the Sediment Source on Slope of Engineering Deposits by Rare Earth Element Tracer Method

[目的]探究生产建设项目工程堆积体坡面侵蚀的泥沙来源,更有针对性地布设水土流失防治措施,减少人为扰动造成的水土流失。[方法]结合室内人工模拟降雨试验与REE(Rare Earth Elements)示踪技术,研究90 mm/h雨强下不同砾石含量[0(纯土),10%,20%,30%]工程堆积体坡面不同坡位的侵蚀特征及侵蚀贡献率。[结果](1)不同砾石含量堆积体各坡位侵蚀量均为下坡位最大,同时下坡位平均侵蚀贡献率(57.40%)大于上坡位和中坡位,表明下坡位是坡面泥沙的主要来源。(2)含砾石堆积体坡面中坡位和下坡位的侵蚀量显著小于纯土堆积体。含砾石堆积体坡面上坡位和中坡位的侵蚀贡献率显著+大于纯土堆积体坡面,下坡位侵蚀贡献率显著小于纯土堆积体坡面。(3)砾石含量对下坡位侵蚀量和贡献率的影响更显著(p<0.05)。含砾石堆积体中,20%砾石含量堆积体坡面上坡位和下坡位的侵蚀量显著大于10%,30%砾石含量堆积体。10%砾石含量堆积体坡面上坡位侵蚀贡献率显著大于20%,30%砾石含量堆积体坡面,下坡位侵蚀贡献率显著小于20%,30%砾石含量堆积体坡面。[结论]各砾石含量工程堆积体坡面中,下坡位侵蚀贡献率均最大,表明下坡位是工程堆积体坡面泥沙的主要来源,要加强工程堆积体下坡位的防护和治理。

[Objective] The aims of this study are to investigate the sediment sources of slope erosion in production and construction projects,and to implement the targeted soil and water conservation measures to mitigate soil and water loss caused by human disturbance.[Methods] Indoor simulated rainfall tests combined with REE tracer technique were conducted to examine the erosion characteristics and contributions from different areas of engineering deposits with varying gravel contents [0(pure soil),10%,20%,30%] under the rainfall intensity of 90 mm/h.[Results](1) The amount of soil erosion of all areas of different gravel-containing engineering deposits was the largest in the down slope area,while the average erosion contribution of the down slope area(57.40%) was larger than that of the upper slope area and the middle slope area,which indicated that the down slope area was the main source of sediment.(2) The erosion contribution of the middle and down slope areas of the gravel-containing engineering deposits was significantly smaller than that of the pure soil deposits.The erosion contribution of the upper and middle slope areas of the gravel-containing engineering deposits was significantly greater than that of the pure soil deposits,and the erosion contribution of the down slope area of the gravel-containing engineering deposits was significantly less than that of the pure soil deposits.(3) The effect of gravel content on the amount and contribution of erosion at the down slope area was more significant(p<0.05).In the gravel-containing engineering deposits,the amount of erosion at the upper and down slope areas of the 20% gravel content engineering deposits was significantly greater than that of engineering deposits with 10% and 30% gravel contents.The contribution of erosion at the upper slope area of the engineering deposit with 10% gravel content was significantly greater than that engineering deposits with 20% and 30% gravel contents,and the contribution of erosion at the down slope area was significantly less than that engineering deposits with 20% and 30% gravel contents.[Conclusion] Among all the engineering deposits with gravel content,the erosion contribution rate of the down slope area is the largest,which indicates that the down slope area is the main source of sediment on the slope of the engineering deposits,and the protection and treatment of the down slope area should be strengthened.