压实延迟对路基水泥改良土工程特性的影响研究  

Effect of Delayed Compaction on the Engineering Characteristics of Cement Improved Soils

作　　者：聂伟 杨飞 宋常军[3] 刘文劼 NIE Wei;YANG Fei;SONG Changjun;LIU Wenjie(Hunan Transportation Research Institute Co.Ltd.,Changsha 410029;Hunan Hengyong Expressway Construction and Development Co.Ltd.,Hengyang 421600;Research Institute of Highway,Ministry of Transportation,Beijing 100088)

机构地区：[1]湖南省交通科学研究院有限公司,长沙410029 [2]湖南省衡永高速公路建设开发有限公司,湖南衡阳421600 [3]交通运输部公路科学研究院道路研究中心,北京100088

出　　处：《土工基础》2024年第5期878-882,共5页Soil Engineering and Foundation

基　　金：湖南省交通科技项目(202214)

摘　　要：针对湖南省某高速公路路基土,配置了不同水泥含量和压实延迟时间的改良土试样,开展多组压实试验和无侧限抗压强度(UCS)测试试验,以评估压实延迟对改良土关键工程特性指标的影响。研究结果发现,随着水泥含量的增加和压实延迟时间的增加,水泥改良土的最大干密度(MDD)会相应减小;压实延迟将降低水泥改良土的UCS值,工程中应尽可能做好搅拌与压实两道工序之间的衔接;随着压实延迟时间增加,水泥改良土刚度降低而韧性增加;基于试验数据建立了考虑压实延迟和水泥含量影响的MDD和UCS回归模型,实测值与模型预测值较为接近。压实延迟必然导致水泥改良土工程特性的变化,在路基填筑中应当合理考虑压实延迟的影响。To investigate the effect of the delayed compaction on the engineering properties of the improved soil,this study focuses on the subgrade soil from an expressway in Hunan Province.Various samples with different cement contents and delayed compaction time were prepared,and multiple series of compaction tests and the unconfined compressive strength(UCS)tests were conducted to assess the influence of the delayed compaction on key engineering characteristics.Subsequently,a regression model was developed to quantify the degree of influence.The findings indicate that the maximum dry density(MDD)of the cement-modified soil decreases with the increasing cement contents and the delayed compaction time.The delayed compaction has an adverse effect on the UCS for the cementimproved soil;therefore,it is crucial to ensure a proper connection between the mixing and the compaction processes.As the duration of the delayed compaction increases,the stiffness of the cement-modified soil decreases while its toughness increases.Regression models for the MDD and the UCS considering both the delayed compaction and the cement contents were established,demonstrating a close agreement between measured values and predicted values.It is important to reasonably consider the impact of the delayed compaction when dealing with the subgrade filling for cement-improved soils.

关 键 词：路基 改良 水泥 压实延迟 最大干密度 无侧限抗压强度 

分 类 号：TU411[建筑科学—岩土工程]