无凝聚性粗粒料用作筑坝材料压实特性研究

Study on the Compaction Properties of Cohesionless Coarse Aggregates Used as Dam Construction Materials

结合长河坝水电站大坝反滤料和过渡料填筑,采用表面振动法进行了系统的相对密度试验研究,得出反滤料和过渡料的最小干密度和最大干密度随着P5含量增减而变化,填料的最大干密度与含水率关系密切,最大干密度随含水率从干到湿呈双峰型变化,说明无凝聚性粗粒填料也只能在充分加水时其压实性最佳,应避免含水率在谷点附近碾压。提出了填料最小干密度和最大干密度的理论计算公式,该方法快速、简捷、经济实用,成果比较符合现场振动碾的工作实际。

The surface vibration method was used to perform the systematic relative density test and study based on the placement of the damfi lter and transition materials of Changheba hydropower project. It is concluded that both minimum dry density and maximum dry density of thefi lter material and the transition material change with increase and decrease of P5 content, and that the maximum dry density of the placed material is closely related with its percent moisture content and the maximum dry density changes with variation of percent moisture content from dry to wet in bimodal distribution, which shows that the placed cohesionless coarse material can reach its best compactibility only when it is suffi ciently wetted, and roller compaction should not be carried out when the percent moisture content is at valley point. The paper puts forward a theoretical calculation formula of minimum dry density and maximum dry density. The method can be implemented in a quick, simple and practical way and the results comparably accord with thefi eld working practice of a vibratory roller.