加筋土竖向变形及筋土相互作用试验研究

发布时间：2018-01-11 11:24

本文关键词：加筋土竖向变形及筋土相互作用试验研究　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着加筋土技术在铁路工程、公路工程建设中的广泛应用,对加筋土技术的深入研究显得更加迫切,尤其是加筋材料在黏性填料中的应用导致了加筋材料与填料之间相互作用的复杂性。在加筋土工程中,加筋材料对土体所提供的约束力强弱决定了填料的加筋效果。影响这一效果的因素很多,本文针对压实度、加筋材料类型、加筋量等因素采用试验手段研究了筋土的相互作用。采用无侧限圆柱体加筋土试样测试了加筋土在竖向荷载作用下,其内部土工格栅的变形发展规律和分布情况,通过设置不同压实度的试样以及素土试样,进行分析比较;采用两种类型土工格栅测试了无侧限圆柱体加筋土试样在长期荷载作用下的竖向变形,研究不同压实度对其竖向变形的影响程度。通过研究获得了如下成果:(1)在土体中布置加筋材料能够提高土体抵抗变形的能力,加筋材料的拉伸模量、筋土间的有效接触面积以及土体压实度对加筋效果有重要影响,加筋材料对土体实际提供的摩阻力大小决定着加筋效果的发挥程度。(2)加筋材料在填料内分层铺设,其约束作用是通过筋土之间的相互作用而产生的。对于黏性填料,加筋土在受荷初期不能立即发挥其加强效应,只有土体的变形达到一定程度之后,其承载能力才会比素土有明显提高。(3)土工格栅应变的大小由格栅周围的土体紧密程度以及该部分土体的运动趋势决定。试样承受的轴向压力,会增加土体的紧密程度;顺着土体挤压扩散的方向,格栅的拉伸应变是最大的。(4)压实度是影响加筋黏土竖向变形的重要因素。提高压实度,可以有效增强加筋土抵抗变形的能力,在同样的荷载下能减小土体的总变形量,使土体变形更快地进入稳定状态。(5)素土和加筋土在长期荷载作用下的轴向应变-时间曲线变化趋势相同,且经历一定时间后,它们的轴向应变与时间的对数基本呈线性关系。
[Abstract]:With the extensive application of reinforced earth technology in railway engineering and highway engineering construction, it is more urgent to study the reinforced earth technology deeply. Especially, the application of reinforced materials in viscous fillers leads to the complexity of the interaction between reinforced materials and fillers. The strength of the binding force provided by reinforced materials determines the reinforcement effect of fillers. There are many factors that affect this effect. This paper aims at the compaction degree and the type of reinforced materials. The interaction of reinforced soil is studied by means of experiment, and the reinforced soil under vertical load is tested by the unconfined cylindrical reinforced soil sample. The deformation development and distribution of geogrid are analyzed and compared by setting samples with different compaction degrees and plain soil samples. Two types of geogrid were used to measure the vertical deformation of unconfined cylindrical reinforced soil specimens under long-term load. The effect of different compaction degree on vertical deformation is studied. The following results are obtained: 1) placing reinforced material in soil can improve the ability of resisting deformation, and the tensile modulus of reinforced material. The effective contact area between reinforcement soil and the compaction degree of soil have an important effect on the reinforcement effect. The friction resistance provided by reinforced material to soil actually determines the exertion degree of reinforcement effect. The constraint is caused by the interaction between the reinforcement and soil. For the viscous filler, the reinforced soil can not play its strengthening effect immediately at the initial stage of loading, only after the deformation of the soil reaches a certain degree. The bearing capacity of the soil is obviously higher than that of the plain soil. 3) the strain of the geogrid is determined by the compactness of the soil around the grid and the movement trend of the soil. It will increase the compactness of soil; Along the direction of soil extrusion and diffusion, the tensile strain of grid is the largest. 4) compaction is an important factor affecting vertical deformation of reinforced clay. Increasing compaction can effectively enhance the ability of reinforced soil to resist deformation. Under the same load, the total deformation of the soil can be reduced, and the deformation of the soil can enter the stable state more quickly.) the variation trend of the axial strain-time curve of the plain soil and the reinforced soil under the long-term load is the same. After a certain period of time, their axial strain and the logarithm of time are basically linear.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU472

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