细颗粒流失对砂砾石土本构关系的影响研究  

Effect of fine grain loss on the stress-strain relationship of sand and gravel soils

作　　者：吴梦喜[1,2] 叶发明 张琦 

机构地区：[1]中国科学院力学研究所,北京100190 [2]中国科学院大学,北京100049 [3]中国电建集团成都水利水电勘测设计研究院,四川成都610072

出　　处：《岩土力学》2017年第6期1550-1556,共7页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划课题(No.2013CB035903);国家科技支撑计划课题(No.2014BAB03B04)~~

摘　　要：采用悬挂式防渗墙的坝基砂砾石土中可能发生潜蚀(suffusion)侵蚀而流失细颗粒,导致土体的强度和变形模量降低,从而对坝基防渗墙及上部坝体造成不利影响。定量描述细颗粒流失量对砂砾石土应力-应变关系影响的模型是定量评估这种影响的基础之一。提出了研究这种本构模型的试验方案,进行了三轴和侧限压缩试验研究了颗粒流失量对应力-应变关系的影响。颗粒流失未改变土体的应力-应变特性,但降低了土体的强度和变形模量。通过建立模型参数与流失量的关系,可以用同一个本构模型描述流失量时空变化的砂砾石土本构关系。基于邓肯E-B模型,建立了模型参数与颗粒流失量之间的定量关系表达式,从而实现了颗粒流失对应力-应变关系影响的定量描述方法。Sand and gravel soils in a dam foundation with a suspended cutoff wall may lead to fine grains loss due to the effect of suffusion, which further results in the reduction of strength and deformation modulus. As a result, the cutoff wall and the dam above the foundation experience an adverse impact. The effect of loss amount of fine particles on the stress-strain relationship of soil is known as one of preconditions to quantitatively assess the impact. In this study, an experimental program was presented to study the constitutive model. Triaxial and confined compression tests were conducted to investigate the effect of the loss amount of fine particles on the strength and stress-strain relations of sand and gravel soils. It is found that stress-strain characteristics of soil are not influenced by fine grain loss, but both the strength and deformation modulus are decreased. By establishing the relationship between model parameters and the amount of the loss, a single model was utilized to describe the stress-strain relationships of sand and gravels with spatio-temporal changes of particle loss amount. Based on Duncan E-B model, we proposed an expression to quantitatively describe the relationship between the loss amount of fine particles and the stress-strain of the soil, and parameters of the constitutive model were given as well.

关 键 词：潜蚀 细颗粒流失 砂砾石 本构模型 

分 类 号：TU441.5[建筑科学—岩土工程]