铁尾矿砂-电石渣复合改良膨胀土的直剪试验研究

Study on direct shear strength of expansive soils improved by iron tailing sands and calcium carbide slag

文章研究工业废料铁尾矿砂、电石渣改良膨胀土的抗剪强度参数,探究它们对膨胀土的改良效果。通过室内试验,分别进行了单掺铁尾矿砂、单掺电石渣、铁尾矿砂与电石渣复合改良膨胀土的直剪试验,研究了不同掺入比与不同含水率对改良膨胀土的抗剪强度指标黏聚力和内摩擦角的影响。结果表明:铁尾矿砂和电石渣均能有效提升膨胀土的抗剪强度,改善其工程性质;采用2种材料的复合改良法效果尤为显著,黏聚力增幅达51.8%,内摩擦角增幅达74.7%;含水率对电石渣改良膨胀土有重要的影响,抗剪强度最高时的含水率比击实试验所确定的最佳含水率高2个百分点。

In order to assess the improving effect of industry wastes on the soil strength,shear strength of the expansive soils mixed with the iron tailing sands and calcium carbide slag was investigated.Direct shear tests were performed on specimens with iron tailing sands,calcium carbide slag,mixed iron tailing sands and calcium carbide slag,respectively,and the effects of different mixing ratios and different water contents on the shear strength indexes of the modified expansive soils such as cohesive force and internal friction angle were studied.Evolutions of cohesive force and internal friction angle indicated the notable improvement of the soil strength due to the incorporation of the iron tailing sands and calcium carbide slag.A notable increasing magnitude of 51.8%in cohesive force and that of 74.7%in the internal friction angle could be observed for the expansive soils mixed with the iron tailing sands and calcium carbide slag simultaneously.Results also showed that the water content had a great effect on the expansive soils treated by calcium carbide slag.The water content corresponding to the highest shear strength of the expansive soils treated by calcium carbide slag was two percentage higher than the optimum water content determined by the compaction test.