初始含水率对风化砂改良膨胀土有荷膨胀率影响研究

Study of impact of initial water content on loaded expansion ratio of expansive soil improved by weathered sand

探讨了利用风化砂作为改良材料抑制膨胀土吸水膨胀特性的可行性与改良效果,试验研究了风化砂掺量对改良膨胀土各项膨胀指标的影响,深入分析了在膨胀土中掺入不同比例的风化砂,改变混合料的初始含水率对有荷膨胀率的影响规律.研究表明:掺风化砂可以有效抑制膨胀土的吸水膨胀,增加风化砂的掺量,膨胀性指标参数会出现较为明显的降低;在同一初始含水率状态下,风化砂的掺入比例从0增加到10%,有荷膨胀率下降的幅度最大.改良膨胀土的有荷膨胀率随着初始含水率的增加呈指数函数下降,当初始含水率小于最佳含水率时,有荷膨胀率随着初始含水率的增加,出现比较明显的降低;当初始含水率大于最佳含水率时,如果继续增大初始含水率,有荷膨胀率的降低则表现不明显.当初始含水率相同时,在较大的上覆荷载作用下,掺风化砂对有荷膨胀的抑制效果较好.

Using weathered sand as improved materials,the feasibility of suppressing swelling characteristics of expansive soil and the improvement effects were explored,the impact of weathered sand content on the expansion ratio of expansive soil was studied,and the impacts of different contents of water and weathered sand on the loaded expansion ratio were analyzed.The research results show that the weathered sand can effectively suppress swelling of expansive soils,and with the increasing of the weathered sand dosage,the decreasing magnitude of swelling index is enhanced.At the same initial water content,within 0to 10% of weathered sand content,the decreasing magnitude of the loaded expansion ratio is the largest.The loaded expansion ratio decreases as exponential function with the increasing of initial water content,and when the initial water content is less than the optimum water content,the loaded expansion ratio decreases obviously with the increasing of the initial water content.When the initial water content is larger than the optimum water content,there is no obvious decreasing of loaded expansion ratio with the increasing of the initial water content.When the initial water content is the same,the larger the overlying loads are,the better the suppressing effect is for loaded expansion mixed with weathered sand.