重庆缙云山典型植被原状土与重塑土抗剪强度研究

Shear strengths of undisturbed and remolded soils of typical vegetations in Jinyun Mountain of Chongqing City

为了从土壤力学方面探索防治水土流失的途径与措施,该文采用直剪仪对重庆缙云山5种典型植被的原状土和重塑土抗剪强度进行试验测定。通过比较相同植被同干密度、同含水率的原状土与重塑土在同一垂直荷载下的剪切差异,分析了根(极细根)在土壤-根系复合体(原状土)中的作用。研究结果表明原状土剪切位移小于重塑土;在相同垂直荷载作用下,同一植被原状土的抗剪强度大于与其同干密度、同含水率的重塑土。原状土的剪切破坏近似于塑性破坏,而重塑土则属于弹性破坏;原状土的抗剪强度与含根量呈正相关,并以此建立关于原状土的抗剪强度回归模型。

In order to find the measures of preventing soil losses based on the soil mechannics, shear strengths of undisturbed and remolded soils of five typical vegetations in Jinyun Mountain of Chongqing city were measured using direct shear apparatus. Through the comparing of shear properties of undisturbed and remolded soils with the same dry density, water content and vegetation at the same vertical load, the effect of roots （the smallest roots） in soil-root composites （undisturbed soils） was analyzed. Results indicate that undisturbed soils have higher shear resistance and less shear displacement than remolded soils which have the same dry density, water content and vegetation at the same vertical loads. Shear failure of undisturbed soils approximately belongs to plastic failure, while shear failure of remolded soils is elastic failure. Shear strength of undisturbed soils has positive correlation with root content, and relevant regression models about undisturbed soil were established.