麦秸秆形状对上海粘土强度影响的试验研究

麦秸秆按形状不同分为圆管状、1/2圆管状及纯茎节状,通过直剪试验和无侧限抗压强度试验比较了不同形状麦秸秆加筋土抗剪强度和无侧限抗压强度的变化规律。试验结果表明:①圆管状与1/2圆管状麦秸秆均可提高上海粘土的强度,直剪试验的最佳加筋率在0.2%~0.3%之间,无侧限抗压强度的最佳加筋率在0.1%~0.2%之间;②1/2圆管状麦秸秆的加筋效果优于圆管状麦秸秆,麦秸秆茎节在一定程度上会降低土体的强度;③无茎节麦秸秆加筋上海粘土可以显著提高素粘土的黏聚力,但对于内摩擦角影响较小。文章还阐述了不同形状麦秸秆加筋土强度变化的作用机理,可为麦秸秆加筋土合理形状的选择提供借鉴。

Effect of Different Shapes of Wheat Straw on the Strength of Reinforced Shanghai Cohesive Soil

Using wheat straw for reinforcement processing of the soil can improve the Shanghai cohesive soil strength. In order to research the influence of the shape of wheat straw, the wheat straw is divided into tubular shape, half tube shape and pure wheat straw stalk. The direct shear test and the unconfined compressive strength test were carried out to compare the strength of reinforced Shanghai cohesive soil by different shapes of wheat straw. The test results show that: ①both the wheat straws with tubular shape and half tube shape can improve the strength of Shanghai cohesive soil; for the direct shear test the best reinforcing effect is at the reinforcing rate between 0.2% to 0.3%,but for the unconfined compressive strength test, the ratio is between 0.1% and 0.2%. ②As far as the shapes of wheat straw are concerned, the half tube shape is better than tubular shape, but in certain extent the wheat straw stalk can reduce the strength of reinforced soil .③Wheat straw reinforced Shanghai cohesive soil can improve the cohesion of the soil, but has little effect on its internal friction angle. This paper also expounds the mechanism of different shapes of wheat straw reinforced soil, which may provide reference for the wheat straw reinforced soil.