重庆市褐色黏土根系固土特性的试验研究

Experimental Research on Characteristics of Brown Clay Soil Reinforcement by Root in Chongqing City

为了解根系在增强褐色黏土抗剪强度中的作用机理,用室内直剪试验研究了根系复合土的应力—应变及强度特征,探讨了有无根系、根系布置位置、根系布置方式和复合体是否含石下的土体抗剪强度。结果表明:纯细粒土表现为脆性破坏,而根系(面积比率(RAR)为0.07%)加入后,根系复合土出现2个强度峰值表现为延性破坏;根系布置在土体位移开始区更利于固土效果;褐色黏土中散生根系固土效果优于垂直根系的固土效果,其根系复合土比无根土的黏聚力c提高了67%、内摩擦角提高了82%;土体中加入一定量D≤2cm碎石的土壤———根系复合体有利于根系固土效果。

To explore the mechanism of shear strength enhancement of roots on brown clay in Chongqing, direct shear tests are carried out to determine the stress-stain and strength characteristics of soil-root composite. The shear strength of soil is investigated in terms of fine-grained soil or soil-root com- posite, different root system positions, different root distribution and gravel contained or not. Results prove that the fine-grained soil shows brittle failure, while soil-root composite shows elastic failure with two intensity peaks after root （area ratio （RAR） 0.07%） being added into the system. Adding the root in the starting area of soil displacement prove to be more conducive to soil reinforcement. Compared to verti- cal soil-root composite, scattered soil-root composite show better effect of solid reinforcement, cohesion and internal friction angle increase by 67% and 82% than those of rootless soil respectively. It is found that certain crushed stone（D ≤2 cm） can reinforce anti-cuts ability of soil-root composite.