初始含水率和改良材料掺量对膨胀土抗剪强度的影响

Effect of initial moisture content and improved material amount on shear strength of expansive soil

为研究不同初始含水率和不同改良材料掺量对膨胀土抗剪强度指标的影响,分别在膨胀土中掺入水泥、石灰、粉煤灰、风化砂进行膨胀土的化学改良,通过改变4种改良材料的掺量及调整膨胀土的初始含水率,进行室内直剪试验。试验结果表明:掺水泥、石灰和粉煤灰能显著提高膨胀土的黏聚力,掺水泥提高黏聚力的幅度最大,其次是掺石灰和粉煤灰,掺风化砂会使膨胀土的黏聚力下降;掺水泥、石灰、粉煤灰和风化砂均能提高膨胀土的内摩擦角,其中掺水泥提高内摩擦角的幅度最大,其次是风化砂。4种材料均可用作膨胀土的改良材料,不同初始含水率及不同改良材料掺量对膨胀土抗剪强度指标的影响十分显著。

To investigate the effect of initial moisture content and improved material amount on shear strength of expansive soil, indoor direct shear test have been done for improved expansive soil respectively mixed with cement, lime, fly ash, and weathered sand, with different improved materials amounts and different initial moisture contents. Tests results show that, soil mixed with cement, lime and fly ash can significantly improve the expansive soil cohesion, with cement having the best improvement effect, followed by lime and fly ash, while soil mixed with weathered sand causes a decline in soil cohesion;soil mixed with cement, lime, fly ash and weathered sand could improve the internal friction angle of expansive soil, and soil mixed with cement improves the internal friction angle most obviously, followed by weathered sand. All the above four materials can be regarded as modified materials for expansive soil, and the effects of different initial moisture contents on shear strength and internal friction angle of improved expansive soil are very significant.