不同加卸载路径下灵敏性粉土的变形特性  

Deformation Property of Sensitivity Silt under Different Loading and Unloading Paths

作　　者：卢瑞娜[1] 余蓉 高原[3] 石雪英 巩天真[1] Lu Ruina;Yu Rong;Gao Yuan;Shi Xueying;Gong Tianzhen(School of Electric Power,Civil Engineer and Architecture,Shanxi University,Taiyuan 0300135,P.R.China;Shanxi electric power engineering Co.,Ltd.,Taiyuan 0300135,P.R.China;Beijing Center for Physical&Chemical Analysis,Beijing100089;Chengdu Design&Resesrch Institute of Building Materials Industry Co.,Ltd.,Chengdu 6100002,P.R.China)

机构地区：[1]山西大学电力与建筑学院,太原030013 [2]山西省电力勘测设计院有限公司,太原030024 [3]北京市理化分析测试中心,北京100089 [4]成都建筑材料工业设计研究有限公司,成都610000

出　　处：《地下空间与工程学报》2024年第2期426-436,共11页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51909204);山西省高等学校科技创新项目(2021L013);山西大学校级大学生创新创业训练计划(X202210108275)。

摘　　要：山西汾河中游一级阶地的施工中发现,饱和粉土地基受扰动后会产生很大的附加沉降,且迟迟不能稳定,表现出灵敏性。基于一维固结蠕变试验研究不同的加卸载路径对灵敏性粉土变形特性的影响,结果表明:加卸载路径和加卸荷比是影响压缩曲线的重要因素;压缩曲线在出现转折时对应的应力为结构屈服应力;加荷比越大,同级荷载下沉降值、固结系数、次固结系数和主固结比都会增大,同时其压缩曲线越趋近于线性,特征转折点消失,但加荷比越大,可大大减少工期;预压荷载的大小和卸荷比都会影响灵敏性粉土的回弹量,预压荷载大于结构屈服应力时,卸荷比越大,回弹量越大,因此需要采取分级卸载方法减小回弹量,保证预压效果;目标荷载小于结构屈服应力时,超载预压法降低工后沉降效果显著。During the construction of the first terrace in the middle reaches of Fenhe River in Shanxi Province,it is found that the saturated silt foundation will have a great additional settlement after being disturbed,and it will not be stable for a long time,showing sensitivity.Based on one-dimensional consolidation creep test,the deformation characteristics of sensitive silt under different loading and unloading paths were studied in this paper.The results show that the loading and unloading path and loading and unloading ratio are important factors affecting the compression curve.The stress corresponding to the turning point of the compression curve is the structural yield stress.The larger the loading ratio is,the larger the settlement,coefficient of consolidation,coefficient of secondary consolidation and primary consolidation ratio under the same loading level increase,and the compression curve becomes more linear and the characteristic turning point disappears,however,the higher the loading ratio,the shorter the construction period.The magnitude of preloading and unloading rate will affect the rebound of sensitive silt.When the preload is greater than the yield stress of the structure,the greater the unloading ratio,the greater the amount of rebound,so it is necessary to take the stepwise unloading method to reduce the amount of rebound to ensure the preloading effect.When the target load is less than the yield stress of the structure,the effect of surcharge preloading method to reduce the post-construction settlement is significant.

关 键 词：加卸载路径 灵敏性粉土 一维固结蠕变试验 结构屈服应力 

分 类 号：TU411.3[建筑科学—岩土工程]