基于状态相关性的土体渗透变形特性试验研究

发布时间：2018-01-15 02:04

本文关键词：基于状态相关性的土体渗透变形特性试验研究　出处：《长沙理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：土体渗透变形问题是工程建设中常见、不可忽视的安全问题。研究表明：土体的颗粒组成特性和土体周围的应力状态对土体的渗透变形特性影响较大。在考虑土体的颗粒组成特性和应力状态的情况下，如何确立一种有效的方法，研究土体的渗透变形机理以及关键水力学参数取值，对采取积极有效的渗控工程处置措施具有十分重要的理论意义和工程实用价值。本文通过总结前人研究成果，采取室内实验的方法，对土体的渗透变特性进行了深入研究，得到了应力状态下土体的渗透变形型式、渗透性变化过程、抗渗强度。主要研究成果如下：（1）对已有的土体渗透变形理论研究发现，而且每种理论均有一定的局限性，对于临界水力坡降的计算，已有的理论更是极少有考虑土体所受应力状态，对此，提出一种应力状态下土体临界水力坡降的计算方法。（2）关于土体的渗透变形实验，特别是应力状态下的土体渗透变形实验，国内没有统一的试验仪器。因此，研制加载式渗透仪，对其中的双杠杆加载装置的工作原理、制作过程、设计特点等做了详细阐述。结合研制的加载式渗透仪，提出相应的试验方法。经过试验使用后，效果很好，能够给土体提供不同的应力状态，而且试验所得结果也表明，更符合工程实际。（3）土体渗透变形型式受细颗粒含量、粘粒的含量、应力状态等因素影响。不含粘粒的试样的破坏型式都为管涌，而含粘粒的试样，粘粒的含量低时，试样渗透变形为管涌。粘粒含量高时，试样渗透变形为水力劈裂。应力状态越高，试样破坏时的渗透变形现象越不剧烈。（4）细颗粒含量、粘粒含量、应力状态等因素对土体渗透性变化过程有着较大影响。不含粘粒或者粘粒含量较少时，试样的渗透性一般是先降低，后升高。当粘粒含量较多时，无附加应力状态下，试样的渗透性在破坏前基本没有变化，破坏后会突然增大，且水力坡降减小，在应力状态下，试样的渗透性在破坏前基本没有变化，破坏后渗透性突然增大，，水力坡降却增大。（5）影响土体抗渗强度的因素很多,细颗粒含量、粘粒的含量、应力状态是其中最重要的几个因素。细颗粒的含量和粘粒含量越高，土体的抗渗强度越高；应力越大，土体的抗渗强度越高。
[Abstract]:Soil seepage deformation is a common problem in engineering construction. Safety issues that cannot be ignored. Studies have shown that:. The particle composition characteristics and the stress state around the soil have a great influence on the seepage deformation characteristics of the soil, considering the particle composition characteristics and the stress state of the soil. How to establish an effective method to study the mechanism of soil seepage deformation and the value of key hydraulic parameters. It is of great theoretical significance and practical value to take active and effective disposal measures of seepage control engineering. This paper summarizes the previous research results and adopts the method of laboratory experiment. The seepage deformation pattern, permeability change process and impermeability strength of soil under stress state are obtained. The main research results are as follows: It is found that each theory has some limitations. For the calculation of critical hydraulic slope, the existing theories seldom consider the stress state of soil. A method for calculating the critical hydraulic gradient of soil under stress state is presented. 2) there is no uniform test instrument for the soil seepage deformation experiment, especially under the stress state. Therefore, the loaded osmometer is developed. The working principle, manufacturing process and design features of the double lever loading device are described in detail. Combined with the developed loading osmometer, the corresponding test method is put forward. It can provide different stress states to the soil, and the experimental results also show that it is more in line with the engineering practice. (3) the seepage deformation pattern of soil is affected by fine particle content, clay content, stress state, etc. The failure pattern of samples without clay particles is piping, while that of samples with clay particles is low. When the content of clay particles is high, the seepage deformation of the specimen is hydraulic fracturing. The higher the stress state, the less the permeability deformation of the specimen is. (4) fine particle content, clay content, stress state and other factors have great influence on the soil permeability. When the clay content is less, the permeability of the sample usually decreases first. Under the condition of no additional stress, the permeability of the sample will not change before failure, but will suddenly increase after failure, and the hydraulic gradient will decrease, under the stress state. The permeability of the sample was not changed before the failure, but the hydraulic slope increased suddenly after the failure. The content of fine particles, the content of clay particles and the stress state are the most important factors. The higher the content of fine particles and the content of clay particles, the higher the impervious strength of soil. The greater the stress, the higher the seepage strength of soil.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU411.4

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