高填方路堤压实土流变性状及路基工后沉降预测

发布时间：2018-02-10 22:13

本文关键词： 高填方压实土加载速率固结蠕变工后沉降　出处：《湘潭大学》2014年硕士论文　论文类型：学位论文

【摘要】：西部大开发战略已经进入了加速发展阶段，交通系统日益完善，在这些地区建设高速公路，无法避免地遇到越来越多的高填方路堤。高填方路堤的路基质量与压实填土的工程性质密切相关，其工后沉降问题也已成为公路交通工程领域的重要研究课题之一，但现阶段对高填方路堤工后沉降预测方法的研究还需要进一步补充和完善。本文以人工制备的路堤压实土为主要对象，开展了压实土的率敏性和一维固结蠕变试验，旨在分析压实土的流变力学特性；由此流变特性结合有限元软件ABAQUS对高填方路堤进行数值模拟，力求为高填方路堤工后沉降预测的研究提供参考，主要内容包括：（1）基于室内常规土工试验的规程，进行了压实土在不同围压下的三轴CD率敏性试验，结果表明，压实土的加载速率力学效应很显著，其CD峰值强度随加载速率的增大，呈现先减小后增大的趋势，具有临界速率现象；压实土在低围压下的应力应变曲线呈明显的应变软化，表明土体压实过程中积累了一定的应力历史，，为重塑超固结土，并随着压实度的提高，应变软化现象增强。（2）对不同加载下的压实土进行了一维固结蠕变试验，分析了压实土的应变与时间、孔隙比与时间对数等关系曲线，发现压实土具有明显的非线性蠕变变形，应力水平越高，蠕变现象越显著。相同条件下，压实度越大，土体的结构性强度表现得越明显，土体的最终累积变形量越小。此外，拟合了压实土的对数形式蠕变方程和含应力影响的幂函数蠕变模型，表征了压实土的应力与应变关系，并从微观角度解释了压实土的蠕变变形机理。（3）结合压实土的流变性状，通过大型有限元软件ABAQUS对兰临高速公路K5+536处高填方路段建立数值模型，并进行分层填筑模拟，分析高填方路堤沉降变形规律，计算结果与实测结果较吻合，由此可为同类型的高填方路堤沉降规律研究及工后沉降预测提供参考。
[Abstract]:The western development strategy has entered the stage of accelerated development, the traffic system becomes more and more perfect, the highway construction in these areas, the high embankment inevitably encounter more and more closely related. The engineering properties of subgrade compaction quality and high embankment fill, the settlement after construction has become one of the important research topics in the field of traffic engineering but the research on prediction method for the settlement of high fill embankment stage also need to further supplement and improve.
In this paper, the compaction of embankment soil artificially prepared as the main object, the rate sensitivity and one-dimensional consolidation creep tests of compacted soil, to analyze the rheological mechanical properties of compacted soil; the rheological properties of the finite element software ABAQUS to simulate high embankment, and strive for the high embankment settlement prediction research the main contents include reference:
(1) for laboratory routine soil test based on the compacted soil under different confining pressure three axis CD rate sensitivity test, the results show that the loading rate of compacted soil mechanics effect is significant, the CD peak intensity increases with increasing loading rate, decreased first and then increased, with critical rate the phenomenon of soil compaction; under low confining pressure stress strain curve showed that strain softening, soil compaction process and accumulated stress history for remolded overconsolidated soil, and with the increased degree of compaction, strain softening phenomenon is enhanced.
(2) the one-dimensional consolidation creep tests on compacted soil under different loading were analyzed, the strain and the compacted soil, the relationship between pore ratio and time logarithm curve, found that the compacted soil has obvious nonlinear creep deformation, the stress level is higher, the creep phenomenon is more significant. Under the same conditions, the degree of compaction large, the structural strength of soil was more obvious, the final cumulative soil deformation amount is small. In addition, the logarithmic form fitting creep equation of compacted soil and water stress on the power function creep model, characterization of compacted soil stress and strain, and explained the mechanism of creep deformation of compacted soil from the microcosmic point of view.
(3) combined with the rheological properties of compacted soil, the finite element software of ABAQUS on LAN Lin highway at K5+536 high embankment numerical model is established, and layered simulation, analysis of high embankment settlement deformation law. The calculated results agree well with experimental results, which can provide reference for prediction of settlement of high embankment of the same type the study on the settlement of and after work.

【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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