水泥改良膨胀土抗剪强度室内试验研究

EXPERIMENTAL STUDY ON SHEAR STRENGTH OF EXPANSIVE SOIL IMPROVED BY CEMENT

为研究水泥改良膨胀土抗剪强度的变化规律,本文以宜昌市小溪塔至鸦鹊岭一级公路改建工程为背景,采用宜昌三峡牌水泥改良膨胀土用作路基填料,并对不同水泥掺量改良膨胀土进行了直接室内剪切试验,深入分析了不同水泥掺量对改良膨胀土的抗剪强度指标的影响及影响规律。研究结果表明:水泥改良膨胀土能明显地提高膨胀土的抗剪强度,掺入水泥之后,内摩擦角和粘聚力均明显提高;随着水泥掺量的增加,改良膨胀土的内摩擦角先逐渐增大,且增大趋势先快后慢,最后逐渐趋于平稳;随着水泥掺量的增加,改良膨胀土的粘聚力逐渐增大,增大的趋势先慢后快,然后逐渐减慢,当水泥掺量从3%增加至5%时,粘聚力增加幅度最大。

For the study of the rule of shear strength of expansive soil improved by cement,this paper takes the ridge level highway reconstruction project as the background,using YiChang three gorges brand cement modified expansive soil used as roadbed filler.With different dosage of cement improved expansive soil direct shear test was carried out.In-depth analysis of the different cement dosage of modified expansive soil shearing strength index of the influence and the influence law.The research results show that the cement improved expansive soil can significantly improve the shear strength of expansive soil,mixed with cement,internal friction angle and cohesive strength were significantly improved;With the increase of cement content,improved expansive soil angle of internal friction increases gradually,and the trend of increase fast after a slow first,and then gradually tend to be stable;With the increase of cement content,improved expansive soil cohesive force increases gradually,increasing trend to slow,quick first,then gradually slow down,when the cement content increases from 3% to 5%,the biggest increase cohesive force.