初始干密度及掺砂比对膨胀土抗剪强度指标影响

研究了风化砂改良膨胀土对抗剪强度及其指标的影响。通过改变风化砂的掺量,研究了风化砂对膨胀土物理性质的影响。试验表明,随着掺砂比例的增加,最佳含水率逐渐下降,渗透系数逐渐增大,说明风化砂能有效降低膨胀土的塑性指数,增大膨胀土的透水性能,使之更适合用作公路路基填料。通过研究风化砂掺入比例及初始干密度对膨胀土抗剪强度指标c、φ值及抗剪强度的影响,可以得出:在掺砂比例一定时,改良膨胀土的粘聚力随着初始干密度的增大而增大,内摩擦角随着初始干密度的增大先增大后减小再增大,抗剪强度值总体逐渐增大;在初始干密度一定时,改良膨胀土的粘聚力随着掺砂比例的增大而减小,内摩擦角随着掺砂比例的增大先增大后减小,抗剪强度总体变化趋势减小。当初始干密度为2.0 g/cm³,掺砂比例为30%时,抗剪强度达到最大值。

The Influence of Initial Dry Density and Doped Sand Proportion on Expansive Soil Shear Strength

In this paper, the weathered sand improved expansive soil shear strength indicators have been studied. By changing the dosage of weathered sand, the influence of weathered sand on expansive soil physical properties was studied. The tests showed that the optimum moisture content gradually decreased with the increase in the proportion of doped sand, gradually increasing the permeability coefficient. Weathered sand can effectively reduce the expansive soil plasticity index and increase the performance of permeability, make the expansive soil more suitable for highway roadbed filler. By studying the influence of initial dry density and doped sand ratio on expansive soil shear strength index (c value and φ value) and the shear strength, a conclusion can be drawn: when doped sand ratio is certain, the cohesion force of improved expansive soil is increasing with initial dry density increasing, the internal friction angle first increases, then decreases and then increases again with initial dry density increasing, the overall shear strength values gradually increase. When initial dry density is certain, the cohesion force of improved expansive soil is first increasing then decreasing with initial dry density increasing, the internal friction angle first increases and then decreases with initial dry density increasing, the overall shear strength values gradually decrease. When the initial dry density is 2.0 g/cm³, the doped sand ratio is 30% and the shear strength reaches a maximum.