5种排水条件下饱和重塑黄土三轴剪切特性  

Triaxial Shear Behavior of Saturated Remolded Loess Subjected to Five Drainage Conditions

作　　者：刘鑫 苗雪青 黄良 魏骁 Liu Xin;Miao Xueqing;Huang Liang;Wei Xiao(School of Geological Engineering and Geomatics,Chang'an University,Xi’an 710064,China;School of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]长安大学地质工程与测绘学院,西安710064 [2]浙江大学建筑工程学院,杭州310058

出　　处：《吉林大学学报（地球科学版）》2023年第5期1499-1509,共11页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(42041006,41927806,41807226);陕西省自然科学基础研究计划项目(2022JQ-251)。

摘　　要：为了深化对工程实践中黄土排水状态和影响的认识,通过三轴剪切试验控制应变增量比研究了饱和重塑黄土在不排水、强制吸水、自由排水、强制排水、部分排水5种排水条件下的剪切特性。结果表明,饱和重塑黄土的剪切特性与排水条件密切相关:在不排水和强制吸水条件下,黄土试样表现为应变软化,从广义上讲,在强制吸水条件下试样的剪胀性被强制发挥;在自由排水和强制排水条件下,黄土试样表现出硬化趋势,其中,在强制排水条件下试样的剪胀性受到抑制;在部分排水条件下,黄土试样为应变软化或应变软化到硬化的过渡状态,此时,黄土的剪切特性不仅与应变增量比有关,也受到孔隙比的影响,应变增量比越接近0,试样的软化程度越明显,而试样的孔隙比越小,其在剪切初始阶段的剪胀趋势越明显,试样的峰值强度和残余强度越高。另外,基于渐近状态方程和剪胀方程,量化分析了饱和重塑黄土的渐近状态和剪胀性,发现试样的渐近状态应力比与剪胀程度呈负相关关系。In order to explore the drainage status and the associated impact of loess in engineering practice,strain increment ratio by triaxial test are used to investigate the shear behavior of saturated remolded loess subjected to five drainage conditions,which are no drainage condition,forced water absorption condition,free drainage condition,forced drainage condition,and partial drainage condition.The results show that,the shear behavior of saturated remolded loess are closely related to drainage conditions.In no drainage condition and forced water absorption condition,the loess samples exhibit strain softening behavior.Taken broadly,under the condition of forced water absorption,the shear expansion of the sample is forcibly exerted.In free drainage condition and forced drainage condition,the loess samples exhibit a strain hardening behavior,and the dilatancy is inhibited in the imposed drained samples.In partial drainage condition,the loess samples show a strain softening behavior or a transition state from strain softening to hardening,in which it is not only related to the strain increment ratio,but also to the void ratio.The closer the strain increment ratio is to 0,the more obvious the softening degree of the sample is.While the smaller the pore ratio of the sample,the more obvious the shear expansion trend is in the initial shear stage,and the higher the peak strength and residual strength of the sample.Besides,based on the asymptotic state equation and the stress-dilatancy relationship,the asymptotic behavior of loess and the associated dilatancy are analyzed.The result shows that the stress ratio of remolded loess at asymptotic state is negatively correlated with the sample dilatancy.

关 键 词：饱和重塑黄土 排水条件 剪切特性 渐近状态 应变增量比 

分 类 号：TU411[建筑科学—岩土工程]