Influence of Polymer Binder on the Physical Properties and Stability of Engineering Spoil on a Slope

An experiment was performed to study the influence of polymer binders on the physical properties,and stability against a simulated rainfall,of a slope consisting of engineering spoil.Results showed that low polymer binder concentrations(≤500g/m3) could enhance the air permeability and moisture-retaining capacity of the engineering spoil;however,adding more polymer binder made the hardness of the engineering spoil increase and then decline.With the increase of polymer binder concentrations,the surface(0-5cm) permeability of the engineering spoil decreased but the permeability of the lower layers(5-10cm) increased.Polymer binders might reduce runoff and sediment,but the effect becomes weaker with the increase of rainfall.The results of this study have significance for engineering practices.Further experiments are needed to study the effects of binders under other conditions,such as natural rainfall,different slopes,different rock types,different degrees and spoil weathering and different added material,and the chemical interaction between soil and polymer binders.

弃渣扰动对藏东山地草甸坡面产流产沙的影响

[目的]明晰铁路修建中弃渣工程扰动引起的水土流失响应,揭示弃渣堆积前后及其植被恢复对藏东生态脆弱的山地草甸区坡面尺度水土流失的影响。[方法]选取未扰动、轻度扰动、重度扰动、覆土恢复4个类型的坡面,建立原位径流小区,通过人工模拟降雨试验,开展了坡面产流产沙过程的研究。[结果](1)坡面的溅蚀量随扰动强度的增大而增加,下坡向的溅蚀量为上坡溅蚀量的1.14~2.67倍。(2)轻度扰动坡面、重度扰动坡面和覆土恢复坡面的初始产流时间分别缩短为未扰动坡面的53.8%~66.7%,34.6%~46.7%,86.7%~92.9%。(3)未扰动坡面、轻度扰动坡面、重度扰动坡面和覆土恢复坡面的产流速率分别为44~86,104~147,200~373,46~95 ml/(min·m^(2)),产沙速率分别为0.026~0.055,0.05~0.098,1.034~2.189,0.047~0.077 g/(min·m^(2))。[结论]覆土恢复坡面的水土保持能力较轻度扰动和重度扰动坡面有显著提高,但距未扰动坡面仍有差距,需采取其他植被或工程措施对工程扰动坡面加以恢复。

无机粘结剂对工程弃渣的物理性状和稳定性的影响

为了确定无机粘结剂对工程弃渣物理性状和抗雨水侵蚀能力的影响,将工程弃渣与自然土壤混合配制成植物生长基质喷附在坡面模型上,开展不同降雨强度下的侵蚀实验。结果表明:无机粘结剂用量小于40kg/m3时,提高了工程弃渣的水分渗透但对水分蒸发有抑制作用,用量大于40kg/m3时无机粘结剂增加了工程弃渣的透气性,但导致工程弃渣保墒能力下降,硬度随之增加。少量的无机粘结剂对于工程弃渣的抗雨蚀能力并无提高,只有在无机粘结剂用量增加到50kg/m3(含)以上时才会显著降低泥沙流失量。无机粘结剂40kg/m3的用量为对工程弃渣物理性状影响的分水岭。而当用量达到50kg/m3临界值时,无机粘结剂开始起到帮助工程弃渣抵御雨水侵蚀的作用。