砂卵石土的流变特性及工程应用研究

发布时间：2018-03-18 12:06

本文选题：砂卵石土　切入点：流变　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：摘要：砂卵石土凭借优良的工程特性,在岩土工程建设中得到大量应用。但是目前针对砂卵石土工程力学特性的研究还不多,特别是流变力学特性研究方面,导致在应对岩土工程事故时没有找到很好的方法。因此,有必要开展砂卵石土的流变力学特性研究以适应当前工程实际的需求。本文采用试验研究、理论分析和数值模拟相结合的研究方法,基于砂卵石土剪切流变试验,运用流变唯象学理论探讨砂卵石土流变力学特性,建立砂卵石土非线性流变本构模型,并将成果应用到岩土工程边坡的稳定性分析中。本文的主要工作及研究成果如下： (1)以砂卵石土边坡为研究对象,进行了级配和含水量等物理特性测试,并按此进行配比研究,获得符合现场条件的砂卵石土人工配比材料,为后续的相关室内试验创造了条件。 (2)在研究含水率、卵石重量、粘土重量对砂卵石土瞬时直剪强度的影响时,提出了“S”(S=卵石重量/粘土重量)值的概念,对不同级配下试样的瞬时直剪强度进行了分析,得出不同“S”值下,砂卵石土瞬时直剪强度的变化规律。 (3)在RYL-600岩石剪切流变仪上进行了砂卵石土直剪流变试验,结果表明,砂卵石土具有很强的非线性流变变形特性,由此提出了改进的七元件粘弹塑性模型用于描述了砂卵石土的粘弹塑性特征。同时将该模型导入到有限元商用数值计算软件中,实现了边坡流变变形的仿真模拟。 (4)以砂卵石土注浆固结体为研究对象,对其进行了单轴压缩流变试验,结果表明,注浆固结体的流变只存在衰减流变和稳态流变两个阶段,广义的粘弹性模型可用来对砂卵石土注浆固结体的流变变形进行模拟,由此建立了相应线性粘弹性流变本构模型。 (5)通过有限元数值仿真模拟计算,对比分析了砂卵石土在注浆前后其边坡的流变变形特性,表明固结注浆方法可有效提高边坡的稳定性系数。
[Abstract]:Abstract: sand pebble soil has been widely used in geotechnical engineering by virtue of its excellent engineering characteristics. However, there are few researches on engineering mechanical properties of sandy pebble soil, especially on rheological properties. Therefore, it is necessary to study the rheological properties of sandy pebble soil in order to meet the needs of current engineering. Based on the shear rheological test of sandy pebble soil and rheological phenomenological theory, a nonlinear rheological constitutive model of sandy pebble soil was established by combining theoretical analysis with numerical simulation. The results are applied to the stability analysis of geotechnical engineering slope. The main work and research results of this paper are as follows:. In this paper, the gradation and moisture content are tested, and according to this, the artificial matching materials of sand and pebble soil are obtained, which will create the conditions for subsequent laboratory tests. 2) in studying the influence of moisture content, pebble weight and clay weight on the instantaneous direct shear strength of sandy pebble soil, the concept of "S" S = pebble weight / clay weight is put forward, and the instantaneous direct shear strength of samples with different gradation is analyzed. The change law of instantaneous direct shear strength of sandy pebble soil with different S value is obtained. The direct shear rheological test of sandy pebble soil was carried out on RYL-600 rock shear rheometer. The results show that sand pebble soil has strong nonlinear rheological deformation characteristics. An improved seven-element viscoelastic-plastic model is proposed to describe the viscoelastic-plastic characteristics of sandy pebble soil. The model is introduced into the finite element commercial numerical calculation software and the simulation of slope rheological deformation is realized. (4) the uniaxial compression rheological tests were carried out on sand pebble soil grouting consolidation body. The results show that there are only two stages of rheological attenuation and steady state rheology of grouting consolidation body. The generalized viscoelastic model can be used to simulate the rheological deformation of sand and gravel soil grouting consolidation body, and the corresponding linear viscoelastic rheological constitutive model is established. Through finite element simulation, the rheological deformation characteristics of sandy pebble soil slope before and after grouting are compared and analyzed. The results show that consolidation grouting method can effectively improve the slope stability coefficient.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU43

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