边坡土壤含水率对不同植被土壤抗剪强度的影响

边坡土壤含水率是影响边坡稳定性的重要因素。本文通过直剪试验，研究边坡土壤含水率对不同植被类型土壤抗剪强度的影响。试验结果显示，天然含水率时，草地土壤抗剪强度高于裸地；随着含水率的增加，土壤抗剪强度及其指标（粘聚力和内摩擦角）基本呈现先增大后减小的趋势，其中裸地土壤抗剪强度在含水率约为10％时达到峰值，草地土壤达到抗剪强度峰值时的含水率约为12％，且草地土壤峰值时的抗剪强度值明显大于裸地；峰值过后含水率继续增加到饱和含水率的过程中，草地土壤抗剪强度减小的幅度小，受含水率变化的影响小。由此表明，边坡植被能显著减弱土壤含水率的增加对土壤抗剪强度的影响，增强边坡土体的稳定性。

Effects of Slope Soil Water Content on Soil Shear Strength of Different Vegetation

The slope soil water content is an important factor that affects the slope stability. Through shear test, effects of slope soil water content on soil shear strength of different vegetation were studied. The test results showed that under the circum- stance of natural water content, soil shear strength of grassland was higher that that of bare land. As the soil water content increased, soil shear strength and its shear strength index namely cohesion and internal friction angle firstly increased and then decreased basically. When the soil water content reached approximate 10%, the soil shear strength of bare land can be up to the peak value. When the soil water content reached approximate 12%, the soil shear strength of grassland can be up to the peak value. Additionally, the peak value of soil shear strength of grassland was obviously higher than that of bare land. When the soil shear strength beyond the peak value and during the course of soil water content increasing over the saturated water content, the decreased magnitude of grassland soil shear strength was low and the effects of the changes of soil water content was light. It was indicated that slope vegetation can effectively decrease the effects of slope soil water content on soil shear strength and enhance the stability of slope soil.