IMHE OpenIR  > 山地灾害与地表过程重点实验室
细粒含量对冰碛土物理力学性质影响的实验研究
Alternative TitleExperimental study on the effect of fine grain content on physical and mechanical properties of moraine soil
蒋德旺
Subtype硕士
Thesis Advisor崔鹏
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline岩土工程
Keyword细粒含量 冰碛土 标度分布 物理性质 力学性质
Abstract冰碛土在高寒山区广泛分布,这类宽级配松散土体在降雨、流水、冰川等作用下运动具有随机性,将导致土体不同部位细粒含量的差异,当前针对细粒含量对冰碛土物理力学性质影响的系统性研究很少,特别是对冻结状态的冰碛土的物理力学性质研究更是少见。土体固体颗粒组成一般都包含了“粗粒”和“细粒”两部分,通常的研究都侧重于分析粗粒部分对土体物理力学性质的影响。但细粒部分对土体的容持水性、渗透性、强度等物理力学性质的影响比粗粒部分更加的重要和复杂,因此,开展细粒含量对冰碛土物理力学性质影响的实验研究具有重要意义。本文为系统探究细粒含量对冰碛土物理力学性质的影响,开展了细粒含量对冰碛土基本物理性质影响的实验研究(包括容持水实验、大型渗透实验)和细粒含量对冰碛土力学性质影响的实验研究(包括常规大型三轴、冻结冰碛土单轴压缩、冻结冰碛土三轴压缩),获得了不同细粒含量对冰碛土容持水性、渗透性、力学性质的影响规律并对机理进行了分析,通过标度分布理论还建立了相应参数与冰碛土物理力学性质的定量关系,得到了以下主要认识和结论:(1)细粒含量对容水度的影响分5个阶段,通过改变土体的孔隙结构和连通性来实现;对持水度的影响分为3个阶段,主要通过改变三类孔隙的孔隙情况来实现。渗透系数随细粒含量的增大呈指数型式的减小,对渗透性的影响是通过改变土体结构来实现的。(2)细粒含量对抗剪强度的影响分为2个阶段,通过对孔隙结构的改造来实现。细粒含量对抗剪强度参数的影响反映出土体结构控制的变化:粗颗粒控制→粗细颗粒共同作用→细颗粒控制。(3)将常规大型三轴实验的结果应用到细颗粒迁移规律中发现:细颗粒迁移导致冰碛堤坡脚和内部一定深度细粒含量较高,达到一定的量值时,抗剪强度会明显降低,冰碛堤容易发生剪切破坏。(4)无论单轴压缩还是三轴压缩,细粒含量48.6%是冻结冰碛土力学性质发生改变的临界值。细粒含量对单轴抗压强度的影响分2个阶段,冻结冰碛土单轴破坏型式存在两种类型是由土体的控制结构不同引起的。细粒含量对抗压强度和抗剪强度变化影响的机理相同,都是由于强度主控因素不同导致的。细粒含量对抗剪强度参数的影响趋势相反。(5)通过标度分布理论建立了相应参数与冰碛土容持水度、渗透系数、强度间的定量关系,这些定量关系可用于预测和评价冰碛土的物理力学性质,具有重要的实际应用价值。
Other AbstractMoraine soil is widely distributed in the high and cold mountainous areas. This kind of loose soil with wide gradation is random under the action of rainfall, water and glacier, which will lead to the difference of fine grain content in different parts of the soil. There are few systematic studies on the influence of fine grain content on the physical and mechanical properties of moraine soil, especially the research on the physical and mechanical properties of frozen moraine soil is rare. The composition of solid particles in soil generally consists of two parts: "coarse grain" and "fine grain". The general research focuses on the analysis of the effect of coarse particles on the physical and mechanical properties of soil. However, the effects of fine particles on the physical and mechanical properties of soil, such as storativity and rentention capacity, permeability and strength, are more important and complex than those of coarse particles. Therefore, it is of great significance to carry out the experimental research on the influence of fine grain content on the physical and mechanical properties of moraine soil.In order to systematically explore the effect of fine grain content on the physical and mechanical properties of moraine soil, the experimental study on the effects of fine grain content on the basic physical properties of moraine soil (including water-holding experiment, large permeability experiment) and the effect of fine grain content on the mechanical properties of moraine soil (including conventional large-scale triaxial compression experiment, uniaxial compression experiment of frozen moraine soil, and triaxial compression experiment of frozen moraine soil). The influence of different fine grain content on the water holding capacity, permeability and mechanical properties of moraine soil was obtained and the mechanism was analyzed. The quantitative relationship between the corresponding parameters and the physical and mechanical properties of moraine soil was established by the scale distribution theory. The following main understandings and conclusions were obtained:(1) The effect of fine grain content on storativity is divided into 5 stages, which is realized by changing the pore structure and connectivity of the soil; the influence of retention capacity is divided into 3 stages, mainly by changing the pore conditions of the three types of pores. The permeability coefficient decreases exponentially with the increase of fine particle content, and the effect on permeability is achieved by changing the soil structure.(2) The influence of fine grain content on shear strength is divided into 2 stages, which is achieved through the modification of the pore structure. The effect of fines content on the shear strength parameters reflects the change of soil structure control: coarse particle control → co-action of coarse and fine particles → fine particle control.(3) The results of the conventional large-scale triaxial compression experiments have been applied to the migration law of fine particles. It is found that the fine particle migration leads to a high level of fine-grained content in the foot and the inner depth of the moraine embankment, and the shear strength will decrease obviously when a certain value is reached, and the moraine embankment is prone to shear failure.(4) No matter uniaxial compression or triaxial compression, the fines content 48.6% is the critical value for the change of the mechanical properties of frozen moraine soil. The effect of fine grain content on uniaxial compressive strength is divided into 2 stages. There are two types of uniaxial failure modes in frozen moraine soil, which are caused by different control structures of soil. The mechanism of the effect of fine grain content on compressive strength and shear strength is the same, which is due to the different strength control factors. The impact of fine grain content on shear strength parameters is reversed.(5) The quantitative relationship between the corresponding parameters and the water holding capacity, permeability coefficient and strength of the moraine soil was established by the scale distribution theory. These quantitative relationships can be used to predict and evaluate the physical and mechanical properties of the morain soil, which has important practical application value. 
Pages124
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24763
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
蒋德旺. 细粒含量对冰碛土物理力学性质影响的实验研究[D]. 北京. 中国科学院大学,2018.
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