【作者】 单志杰；

【导师】 张兴昌；

【作者基本信息】 中国科学院研究生院（教育部水土保持与生态环境研究中心） ， 土壤学， 2010， 博士

【摘要】 公路路基边坡的防护措施是公路水土保持中的重要组成部分,开展公路路基边坡防护措施研究对公路水土保持建设实践具有重要意义。采用室内土壤理化性质试验和人工模拟路基边坡冲刷试验的研究方法,系统地研究了EN-1离子型土固化剂掺量(0、0.01%、0.05%、0.10%、0.15%、0.20%)对0-30 cm和30-100 cm土层塿土和黄绵土水分有效性、结构稳定性、入渗性、抗崩解性及土壤有机质含量、土壤酸度等理化性质的影响,探讨了不同EN-1固化剂掺量和掺入厚度(0、5、10、15、20 cm)时,黄土路基边坡坡面水土流失规律、坡面流特征及抗冲刷性能,优选出了适用于不同土质和土层黄土的最佳固化剂掺量及掺入厚度。通过逐步回归分析法建立的土壤侵蚀量预测模型,阐明了EN-1离子型固化剂对坡面土质的加固机理。论文所取得的主要结论如下:1、EN-1固化剂可降低土壤水分的有效性,固化剂掺量越高,影响越大。其中,对塿土水分有效性的影响略大于黄绵土,对上层土壤(0-30 cm土层)水分有效性的减弱作用明显高于下层土壤(30-100 cm土层)。固化剂掺量大于0.15%后,有利于改善塿土和0-30 cm黄绵土土壤结构性能,掺量0.20%对土壤结构的优化效果最为显著;掺量大于0.01%时,有利于提高土壤结构稳定性,掺量0.15%效果最为显著。在黄绵土30-100 cm土层中,固化剂优化了土壤结构、提高了土壤结构稳定性,掺量0.01%时土壤结构最优,掺量0.20%时结构稳定性最优。2、固化剂掺量在0.10%~0.15%时,塿土和黄绵土均具有最大的土壤入渗能力。固化剂明显提高了土壤的抗崩能力,较高掺量(≥0.15%)对塿土抗崩性能的提高效果更为明显,而适中的掺量(0.10%)则更适合黄绵土抗崩性能的提高。固化剂掺量越高,土壤有机质含量越高,pH值越低。3、路基边坡土壤加入固化剂后,增加了坡面流平均流速,降低了坡面流侵蚀动力,坡面流态为层流、急流。其中,固化剂掺量对黄绵土坡面流速的增加效果大于塿土,对塿土坡面流态的影响较大,对黄绵土坡面流态影响较小。固化剂的掺入降低了黄土坡面的产流量和产沙量,掺量0.10%时降低效果最为显著。固化剂掺量对塿土边坡产流量和产沙量的影响效果大于黄绵土,对0-30 cm土层的边坡产流量影响效果大于30-100 cm土层,而对边坡产沙量的影响效果与之相反。4、在塿土中,EN-1掺入厚度为15 cm的固化土边坡坡面流速最大,20 cm最小;在黄绵土中,掺入厚度10 cm的固化土边坡坡面流速最小,20 cm最大。不同掺入厚度时的塿土和黄绵土坡面流态均为层流、急流。10 cm厚度时坡面流雷诺数和阻力系数最大,弗洛德数最小;20 cm厚度时雷诺数和阻力系数最小,弗洛德数最大。掺入厚度越大,塿土坡面产流量越小,黄绵土坡面产流量越大,20 cm厚度固化土边坡产沙量最低,坡面最稳定。5、利用逐步线性回归分析法建立的土壤侵蚀量预测模型能较好的评价黄土路基边坡土壤的可蚀性,预测土壤侵蚀量,阐明固化剂对不同土质边坡的加固机理。在塿土0-30 cm土层,固化剂通过增加土壤的饱和导水率和毛管饱水稳性团聚体含量,减小土壤静水崩解速率加固边坡;在塿土30-100 cm土层,固化剂通过增加土壤的有机质含量,降低土壤的饱和含水量加固边坡;在黄绵土0-30 cm土层,固化剂通过降低土壤的静水崩解速率和pH值加固边坡;在黄绵土30-100 cm土层,固化剂通过降低土壤的静水崩解速率和饱和含水量,增加风干土水稳性团聚体含量加固边坡。综合EN-1离子固化剂掺量对黄土边坡土壤的水分有效性、结构性、入渗性、抗崩性、肥力、酸性及抗冲刷性能的影响后,建议在黄土地区路基边坡坡面防护工程中应用EN-1土壤固化剂时,最佳掺量选择为0.10%左右,掺入厚度选择为20 cm时即可显著提高黄土路基边坡坡面土壤抵抗径流冲刷的能力,防止因坡面侵蚀破坏而引起的边坡失稳。更多还原

【Abstract】 The protective measures for highway subgrade slope are an important component of soil and water conservation on highway and the study on them have important significance to the construction of highway soil and water conservation. Through the laboratory test and theory analysis, this text studied the influences of the EN-1 contents(0, 0.01%, 0.05%, 0.10%, 0.15%, 0.20%)on physical and chemical properties for tier soil and loessal soil in the 0-30 cm and 30-100 cm layers, including soil water availability, structural stability, permeability, collapsibility, organic matter and acidity,analyzed soil erosion law,overland flow characteristics and scour resistance with six EN-1 contents and five EN-1 depths,and selected the appropriate EN-1 content and depth. By stepwise regression analysis to establish wash erosion prediction models, and explained the reinforcement mechanism of EN-1 plasma soil stabilizer to the slope soil. Main results are as follows:1. EN-1 reduces the effectiveness of soil moisture, the higher the content, the greater the effect was, the impact on tier soil was slightly larger than that in the loessal soil and on the upper soil (0-30 cm layer) was significantly higher than that in the subsoil (30-100 cm layer). For the tier soil and loessal soil in the 0-30 cm, it was greater benefit to improve soil structural performance since the content was greater than 0.15%, and the 0.20% content was most excellent; it was greater benefit to improve soil structural stability since the content was greater than 0.01%, and the 0.15% content was most excellent. For the loessal soil in the 30-100 cm, they were useful to improve soil structure and stability by using EN-1, and the best soil structure was at 0.01% content, the optimal structural stability was at 0.20% content.2. When the EN-1 contents were from 0.10% to 0.15%, the soil permeability was the largest. The soil resistance to collapse was significantly improved by using EN-1, when the EN-1 contents were more than 0.15% for tier soil, the soil resistance to collapse was more significantly increased; when the EN-1 contents were 0.10% for loessal soil, the soil resistance to collapse was more significantly increased. The higher the content, the higher the soil organic matter content and the lower pH value were.3. Adding EN-1 soil stabilizer into the subgrade slope soil, the mean runoff velocity was increased, and the erosion power was decreased, besides, the runoff morphology was laminar and rapid flow, the impact on the loessal soil slope runoff mean velocity was larger than that in tier soil, EN-1 had a great effect on runoff morphology on tier soil slope and little effect on loessal soil slope. Runoff and sediment yield on the slope were reduced by adding EN-1 into the subgrade slope soil, they were the lowest at the 0.10% content. EN-1 contents had a greater effect on runoff and sediment yield on the tier soil slope than that on the loessal soil slope, the impact on the upper soil (0-30 cm layer)slope runoff was significantly higher than that in the subsoil (30-100 cm layer) and the sediment yield was opposite .4. The maximum mean runoff velocity was got when EN-1 applied depth was 15 cm, while it was the minimum at 20 cm in the tier soil. The maximum mean runoff velocity was got when EN-1 applied depth was 20 cm, while it was the minimum at 10 cm in the loessal soil. The runoff morphology was laminar and rapid flow at different applied depth. The largest Re and f and the smallest Fr were got when the EN-1 applied depth was 10 cm; while the smallest Re and f and the largest Fr were got when the EN-1 applied depth was 20 cm. The deeper of the EN-1 applied, the smaller runoff was in the tier soil slope, while the larger of the runoff in the loessal, the lowest sediment yield was and the slope was the most stabilization.5. Through the stepwise multiple linear regression analysis, the models and indicators for assessing the soil erodibility from these properties was constructed, and they explained reinforce mechanisms of EN-1 to the loess slope with different soil types by. In the 0-30cm layers of tier soil, the slope was reinforced through the increasing of soil saturated hydraulic conductivity and the water-stable aggregates and the decreasing of soil collapse velocity; In the 30-100 cm layers of tier soil, the slope was reinforced through the increasing of organic matter content and the decreasing of saturation moisture content; In the 0-30 cm layers of loessal soil, the slope was reinforced through the decreasing of soil collapse velocity and PH; In the 30-100 cm layers of loessal soil, the slope was reinforced through the increasing of dry aggregates and the decreasing of soil collapse velocity and saturation moisture content. Comprehensive consideration on EN-1 soil stabilizer contents affection on soil water availability, structural stability, permeability, collapsibility, organic matter, acidity and scour resistance, the paper suggests that EN-1 soil stabilizer can be used in protection engineering of highway subgrade slope for loess region, and the optimum content is around 0.10% and depth is 20cm can increase the ability of soil resistance runoff scour of slope significantly, and it can prevent slope instability caused by slope erosion damage.更多还原