水蚀风蚀交错区黄土抗剪强度敏感性分析

抗剪强度不仅是黄土重要的力学性质指标，还是控制重力侵蚀的内在因素。利用直剪仪进行快剪试验，研究干密度和含水量对黄土抗剪强度的影响，并用基于变量增长率的敏感性分析方法，对抗剪强度的影响因素进行了敏感性分析。结果表明:干密度是通过影响粘聚力和内摩擦角来影响抗剪强度的，而含水量仅仅通过影响粘聚力来影响抗剪强度。含水量对粘聚力的影响呈指数函数减小，而对内摩擦角影响很小，含水量对粘聚力的影响程度是其对内摩擦角的18.5倍。黄土抗剪强度对干密度的敏感性大于它对含水量的敏感性，前者的敏感系数是后者的10倍。可为黄土沟坡重力侵蚀的力学机理分析提供参考依据。

Sensitivity on Shear Strength of the Loess in the Ecotone of Wind-Water Erosion

The shear strength is not only an important mechanical index of the loess, but also a significant factor associated with gravity erosion.We carried out a series of quick direct shear tests on the remolded loess samples, and then evaluated the sensitivity on the shear strength of the dry density and moisture content using the increase-rate-analysis method. The experimental results reveal that the dry density could markedly affect the shear strength with changes in the cohesive force and internal friction angle, while the moisture content might markedly influence the shear strength with changes in the cohesive force. In addition, the influence of the moisture content on the internal friction angle was small, but that on the cohesive force was obvious. The cohesive force decreased with the increase of the moisture content at an exponential rate. On the other hand, the effect of the cohesive force on the water content was about 18.5 times higher than that on the internal friction angle. Moreover, the sensitivity parameter on the shear strength of the dry density was much larger than that of the moisture content, and the sensitivity of the former was 10 times that of the latter. The results can provide an insight into the mechanics mechanism and process of gravity erosion on the steep loess slope.