基于滑移线场理论的高填路堤稳定性研究

发布时间：2019-03-08 15:08

【摘要】：在自重、降雨、外部载荷等因素的作用下,高填路堤出现了各种不同形式的破坏。研究高填路堤稳定性,可以有效的防治路堤失稳破坏,避免不必要的经济损失。本文借助有限元软件Abaqus进行数值模拟分析,编写基于滑移线场理论的有限元后处理Matlab程序,对高填路堤在不同工况条件下的稳定性进行研究。首先,本文对滑移线场理论进行了大量的文献调研,阐述了滑移线场理论的基本原理。其次,首次利用滑移线场理论,探究高填路堤在不同工况条件下稳定性的基本规律。数值模拟结果表明:高填路堤三台阶情况下,增大第三台阶的高度,路堤安全系数增大;在第一台阶和第三台阶坡度不变情况下,放缓第二台阶坡度,路堤安全系数增大;在不同的换填土强度参数情况下,安全系数随着内摩擦角和黏聚力的增大而增大,但是增大趋势有所减缓。当内摩擦角增大到30°、黏聚力增大到30 kPa的时候,对塑性区范围和临界滑动面的位置影响逐渐减弱,其中内摩擦角对塑性区的范围影响更大。根据临界滑动面的变化趋势和最小安全系数,建议换填后的材料强度参数应选取黏聚力大于20 kPa、内摩擦角大于20°。最后,选取广佛肇高速典型高填路堤作为分析实例,分析了高填路堤基底在换填前后的安全系数和临界滑动面的变化趋势。数值模拟结果表明:换填后,路堤安全系数有了较大幅度的提高,并且大于1.300,临界滑动面逐渐上移,滑动土体范围逐渐变小;验证了原设计方案的可靠性,提出了安全经济的台阶高度组合设计方案。
[Abstract]:Under the influence of gravity, rainfall, external load and other factors, there are various kinds of destruction of high fill embankment. The study on the stability of high filling embankment can effectively prevent the instability and damage of embankment and avoid unnecessary economic loss. In this paper, with the help of finite element software Abaqus, the finite element post-processing Matlab program based on slip-line field theory is compiled to study the stability of high-fill embankment under different working conditions. Firstly, this paper makes a great deal of literature investigation on the slip line field theory, and expounds the basic principle of the slip line field theory. Secondly, the basic law of stability of high fill embankment under different working conditions is studied by using slip line field theory for the first time. The results of numerical simulation show that when the height of the third step is increased, the safety factor of the embankment increases when the slope of the first step and the third step is constant, the slope of the second step is slowed down and the safety factor of the embankment increases when the slope of the first step and the third step is constant. Under different strength parameters, the safety factor increases with the increase of internal friction angle and cohesion, but the increasing trend decreases. When the internal friction angle increases to 30 掳and the cohesion force increases to 30 kPa, the influence on the range of plastic zone and the position of critical sliding surface decreases gradually, and the influence of internal friction angle on the range of plastic zone is greater. According to the change trend of critical sliding surface and the minimum safety factor, it is suggested that the internal friction angle greater than 20 掳should be selected for the strength parameters of the material after replacement. Finally, taking the typical high-fill embankment of Guangfuzhao highway as an example, the change trend of safety factor and critical slip surface of the high-fill embankment foundation before and after replacement is analyzed. The numerical simulation results show that the safety factor of embankment has been greatly improved after replacement, and more than 1.300, the critical sliding surface gradually moves up, and the scope of sliding soil gradually becomes smaller; The reliability of the original design scheme is verified and a safe and economical step height combination design scheme is put forward.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.12

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