结构性对昆明泥炭质土层压缩特性影响的试验  

Experiment of structure effect on compressibility of peaty soil in Kunming

作　　者：王志良[1] 瞿嘉安 申林方[1] 丁祖德[1] WANG Zhiliang;QU Jiaan;SHEN Linfang;DING Zude(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming,Yunnan 650500,China)

机构地区：[1]昆明理工大学建筑工程学院,云南昆明650500

出　　处：《江苏大学学报（自然科学版）》2018年第3期337-342,354,共7页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51668028;51508253;51408284);云南省应用基础研究计划项目(2016FB077)

摘　　要：为了研究昆明泥炭质土结构性对其压缩特性的影响,对取自于埋深16.5~17.0 m的原状土样与扰动土样进行了一维压缩试验.结果表明:采用作图法求得原状土样的前期固结压力为91~105 k Pa,超固结比为0.71~0.82,土体处于欠固结状态,而扰动土样的固结屈服压力仅为60~72k Pa,表明泥炭质土具有较强的结构性;由于受到土体结构性的影响,固结压力较小时,原状土样的压缩指数小于扰动土样,随着固结压力增加,原状土样结构破坏,其压缩指数逐渐增大,并超过扰动土样;随着荷载的增大,压缩量急剧增加,原状土样、扰动土样所对应的各级固结系数均呈减小趋势;昆明泥炭质土的次固结系数为0.071~0.101,而次压缩系数为2.00%~2.85%,属于高次压缩性或很高次压缩性土体.To investigate the effect of structure on the compressibility of peaty soil in Kunming,Yunnan,a series of one-dimensional compression tests were carried out for disturbed and undisturbed soil samples with depth from 16.5 to 17.0 m.The test results show that by drawing method,the pre-consolidation pressure is 91~105 kPa,and the over consolidation ratio is 0.71~0.82,which illuminates that the soil is in the under consolidated state.The consolidation yield stress of disturbed soil samples is only 60~72 kPa,which shows that the peaty soil has strong structure.Due to the influence of soil structure,the compression index of undisturbed soil samples is less than that of disturbed ones when the consolidation pressure is small.With the increasing of consolidation pressure,the structure of undisturbed soil samples is destroyed,and the compression index is gradually increased and exceeds that of disturbed soil samples.With the increasing of load,the compression amount increases sharply,and the consolidation coefficients of both undisturbed and disturbed soil samples show decreasing trend.The secondary consolidation coefficient is 0.071~0.101,and the secondary compression coefficient is 2.00%~2.85%,which can be classified as a soil with high or very high secondary compressibility.

关 键 词：泥炭质土 一维压缩特性 扰动土 固结试验 压缩指数 

分 类 号：U411[交通运输工程—道路与铁道工程]