路基黏土-砂混合填料的工程特性

Engineering Characteristics of Clay-Sand Mixed Filler for Subgrade

为研究路基黏土-砂混合填料的工程特性,本文选取高岭土和石英砂,分别制备不同含砂率与含水率的黏土-砂混合物试件,开展轻型击实、液限塑限联合测定、自由膨胀率、承载比(CBR)、无侧限抗压强度试验。结果表明,随着含砂率增加,黏土-砂的最大干密度升高,最佳含水率、塑限、液限、塑性指数降低。在相同含砂率下,黏土-砂的CBR值随着含水率上升先增后减。若含砂率上升,则黏土-砂的最大CBR值升高,最大CBR值所对应的含水率降低,黏土-砂满足作为路基填料的CBR值要求时,所对应的含水率范围明显收窄。随着含水率或含砂率增加,黏土-砂的自由膨胀率与无侧限抗压强度均减小。相比于含砂率,含水率对黏土-砂无侧限抗压强度的影响更显著。

In order to study the engineering characteristics of the clay-sand filler of subgrade.In this paper,kaolinite and quartz sand were selected to prepare the clay-sand mixture samples with different sand and water contents,respectively.The tests including the light compaction,joint determination of liquid limit and plastic limit,free expansion rate,California bearing ratio(CBR)and unconfined compressive strength were conducted.The results indicate that with the increase of sand content,the maximum dry density of the clay-sand increases,while the optimal water content,plastic limit,liquid limit,and plasticity index all decrease.Under the same sand content,as the water content increases,the CBR value of the clay-sand increases first and then decreases.If the sand content increases,the maximum CBR value of the clay-sand increases,and the water content corresponding to the maximum CBR value decreases.When the clay-sand meets the CBR value requirements as the subgrade filler,the corresponding water content range significantly narrow.With the increases of water content or sand content,the free expansion rate and unconfined compressive strength of the clay-sand decrease.Compared with the sand content,the influence of the water content on the unconfined compressive strength of the clay-sand is more significant.