为了探究三峡水库消落带根土复合体抗剪性能的影响机制,以狗牙根根土复合体为研究对象,利用三轴试验,定量分析含水率、干湿交替次数以及含根量对根土复合体抗剪性能的影响。结果表明:(1)随着干湿交替次数和含水率的增加,土壤抗剪性能逐渐劣化,含水率13%的根土复合体抗剪强度依次比含水率18%、含水率23%的土壤抗剪强度提高0.12%~14.76%,12.47%~21.14%;经历干湿交替6次与3次的根土复合体抗剪强度比经历1次的降低6.31%~14.71%与2.41%~8.19%。(2)根系含量能显著影响土壤抗剪性能,含根量为1.5 mg/cm3的土壤抗剪强度比含根量为0.5 mg/cm3的土壤抗剪强度提高0.86%~21.10%,内摩擦角增长0.09%~16.31%,黏聚力增长2.27%~30.55%。(3)含水率是影响土壤抗剪性能最主要的因素,对抗剪强度的贡献程度排序上为含水率(61.30%)>干湿交替次数(21.17%)>含根量(8.28%)。研究结果为消落带固土护岸的物种筛选、群落构建、水土保持生态建设、生态系统重建以及水库岸线管理等提供科学依据。
In order to explore the impact mechanism of the shear resistance of root-soil composite in the Three Gorges Reservoir's water-level fluctuation zone, this study took root-soil composite of Cynodon dactylon as the research object, and used the triaxial test to quantitatively analyze the influence of water content, dry-wet alternate times and root content on the shear resistance of root-soil composite. The results showed that:(1) With the increasing of dry-wet alternate times and water content, the soil shear resistance gradually deteriorated. The shear resistance of the root-soil composite with 13% water content was 0.12%~14.76% and 12.47%~21.14% higher than that of the soil with 18% water content and 23% water content, respectively. The shear resistance of the root-soil composite subjected to 6 and 3 cycles of dry-wet alternation was 6.31%~14.71% and 2.41%~8.19% lower than that subjected to one cycle of dry-wet alternation. (2) Root content could significantly affect the soil shear resistance, and the soil shear resistance with root content of 1.5 mg/cm3 was 0.86%~21.10% higher than that with root content of 0.5 mg/cm3. The internal friction angle increased by 0.09%~16.31%, and the cohesion increased by 2.27%~30.55%. (3) Water content was the dominant factor affecting the soil shear strength. The order of contribution to the shear resistance was water content (61.30%) > dry-wet alternate times (21.17%) > root content (8.28%). This study provided scientific reference for species screening, community construction, ecological construction of soil and water conservation, ecosystem reconstruction, and reservoir management in the water-level fluctuation zone of the Three Gorges Reservoir.
郑晓岚, 鲍玉海, 贺秀斌, 谢航宇, 王英培.周期性淹水对水库消落带根土复合体抗剪性能的影响[J].水土保持学报,2023,37(5):111~120复制