路堤下草甸土地基中应力分布规律研究

Study on Stress Distribution Rule of Meadow Soil Ground Under Embankment

为了研究草甸土的加筋机理及路堤下草甸土地基中的应力分布规律,以新疆伊犁昭苏垦区吐坡公路路堤下草甸土地基为研究对象,采用草炭土与素土按不同比例混合,通过室内试验测试了混合土的密度、含水率、黏聚力、内摩擦角等参数,并运用模糊数学理论对混合土与草甸土的相似性进行了评判,确定了草甸土的相似土体。在此基础上,通过室内大比例尺模型试验,考虑路堤形状及柔性加载的作用,模拟了均质软土地基与草甸土地基上路堤的填筑过程,研究了路堤下软土地基地表有、无草甸土层时地基中的应力分布规律,并将试验结果与有限元数值分析结果进行了对比分析。结果表明:地表草甸土层的存在可以有效地减小路基中心线附近的附加应力,而路基边坡下地基中的附加应力则有所增大,地表草甸土层具有较好的应力扩散作用;地表有一定厚度的草甸土层可以提高地基的容许承载力。

In order to investigate the reinforcement mechanics of meadow soil and the stress distribution rule of meadow soil ground under embankment,based on the meadow soil ground under the embankment of Tupo Highway at Zhaosu reclamation region in Yili of Xinjiang,the turfy soil was mixed with the plain soil at different percentages,and the density,water content,cohesion,internal friction angle of the mixed soil were tested in the laboratory.Then the fuzzy mathematics theory was used to evaluate the similarity of the mixed soil and the natural meadow soil,and the similar soil of meadow soil was determined.Based on this,through the large scale model test in the lab,considering the effects of embankment shape and flexible loading,the construction process of the embankment on the homogeneity soft ground or on the ground with meadow soil was simulated,the stress distribution rules of soft ground with or without meadow soil were analyzed,and the tested results were compared with the FEM calculated results.The results show that the additional stress near the center line of the embankment decreases,while theadditional stress under the slope increases because of the meadow soil at the ground surface,which means that the meadow soil can distribute the stress to a wider area when the embankment is built on it.The meadow soil with certain thickness can enhance the bearing capacity of the soft ground.