基于颗粒离散元方法的边坡动力相应规律研究

发布时间：2018-04-29 10:12

本文选题：颗粒离散元 + 动力响应　；参考：《西南交通大学》2016年硕士论文

【摘要】：我国是一个地震多发国家,且地震带与山区位置相重合,地震诱发的滑坡会对生命财产安全造成极大威胁,开展边坡动力响应研究对于防灾减灾有重要意义。颗粒离散元方法是目前模拟岩土体这种非线性材料相对最合理的一种方法,且离散元法单元可以破裂,不存在计算收敛问题,能够模拟边坡在动力作用下损伤累积直至破坏的全过程。本文在颗粒离散元软件(PFC)的基础上开展了边坡动力响应模拟。本文首先利用颗粒流软件重现了一个振动台试验,通过试验结果对比证明了颗粒离散元方法的合理性,其可以作为振动台试验的一种替代方法进行边坡动力响应规律研究。通过计算和分析均质土坡的动力响应过程,总结出了均质土坡在动力作用下的破坏机制——拉-剪配合作用机制。通过归纳不同坡体材料均质单面坡模型的速度放大系数,总结出边坡在动力作用下会激发四种振型,且四种振型随着边坡高度的增加依次出现。通过计算和研究双面坡在横向正弦波、横向地震波、竖向地震波以及二维地震波四个工况下的动力响应,发现竖向地震对于边坡的破坏作用非常明显。并且发现当竖向地震作用现发生破坏时,耦合横向地震会使破坏效果减轻。变坡度山体最容易产生破坏,其比较独特的地方在于很容易在变坡度的坡肩位置产生拉裂缝,而该拉裂缝的走向非常有利于滑动面的最终产生。通过初步计算几种不同的节理型边坡,得到顺倾层状边坡在正弦剪切波作用下产生拉裂-溃滑型破坏,坡面平行节理边坡在竖向地震作用下产生压弯-剪断型破坏,反倾层状节理边坡在竖向地震作用下产生剪断-溃滑型破坏,断续裂隙边坡在动力作用下,岩桥很容易贯通,其破坏模式为岩桥贯通-滑面成形-滑移拉裂。
[Abstract]:China is an earthquake-prone country, and the seismic zone coincides with the location of the mountain area. Earthquake induced landslides will pose a great threat to the safety of life and property. It is of great significance to carry out the study of slope dynamic response for disaster prevention and mitigation. The particle discrete element method is the most reasonable method to simulate the nonlinear material of rock and soil at present, and the element of discrete element method can be broken, and there is no problem of computational convergence. It can simulate the whole process of slope damage accumulation and failure under dynamic action. In this paper, the dynamic response of slope is simulated on the basis of particle discrete element software (PFC). In this paper, a shaking table test is first reproduced by using the particle flow software, and the rationality of the particle discrete element method is proved by comparing the test results, which can be used as an alternative method to study the dynamic response law of the slope. By calculating and analyzing the dynamic response process of homogeneous soil slope, the failure mechanism of homogeneous soil slope under dynamic action is summarized. By inducting the velocity magnification factor of the homogeneous single-side slope model of different slope materials, it is concluded that four modes of vibration will be excited under the dynamic action of the slope, and the four modes will appear in turn with the increase of slope height. By calculating and studying the dynamic response of the double-sided slope under four working conditions: transverse sine wave, transverse seismic wave, vertical seismic wave and two-dimensional seismic wave, it is found that the vertical earthquake has a very obvious failure effect on the slope. It is also found that the coupling lateral earthquake can reduce the damage effect when the vertical earthquake occurs. It is very easy to produce tensile cracks in the position of slope shoulder with variable slope, and the strike of the tensile crack is very conducive to the final generation of sliding surface. The slope of the mountain is easy to be destroyed, and its unique feature is that it is easy to produce a tensile crack in the position of the shoulder of the slope with a variable gradient. Based on the preliminary calculation of several different jointed slopes, it is obtained that the inclined layered slopes are subjected to tensile cracking and sliding failure under the action of sinusoidal shear waves, and the parallel jointed slopes on the slope face are subjected to compression, bending and shear failure under vertical earthquake. Shear collapse and slip failure occur in reverse inclined layered jointed slope under vertical earthquake, and rock bridges are easily penetrated under dynamic action of intermittent fractured slope. The failure mode of rock bridge is form-slip tensile fracture of rock bridge.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU435

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