粗粒土边坡的塑性带发展过程模拟和稳定性研究

发布时间：2018-07-11 11:34

本文选题：粗粒土 + 模型试验　；参考：《江苏科技大学》2017年硕士论文

【摘要】：土体的失稳破坏过程与塑性带的扩展密切关联,对于塑性带扩展过程的数值模拟和试验研究将有利于推进对土坡渐进破坏的理解和描述,对该方面的研究将对进一步深刻揭示边坡失稳过程有着重要意义和影响。本文针对粗粒土边坡开展了边坡在极限状态下土中塑性带发展变化的模型试验和数值模拟,研究粗粒土边坡的失稳规律,并在此基础之上对边坡稳定性进行了分析研究,研究的结论如下:(1)通过自制的模型槽对粗粒土边坡中塑性带的发展过程开展了试验研究。在试验过程中,对极限状态下边坡整体滑动形式和关键点的位移变化进行了实时记录,并通过预埋应力盒和植入特制金属丝等手段对塑性带内外土中的应力、应变的变化情况以及塑性带的宽度进行了有效的监测和数据的采集,以此来揭示塑性带所存在的一些特性,即塑性带的发展过程是一种渐进式的,其发展起始于应力应变曲线的峰值之前,形成于峰值之后;同时得到边坡在失稳破坏时的滑动形式是由直线段和圆弧段相结合的混合型破坏模式。(2)针对影响塑性带的相关参数进行了研究。结合试验和有限元分析开展了土体粘聚力、内摩擦角、土体重度以及试样颗粒粒径的变化对塑性带宽度和位置形态影响的数值分析,获得了土体强度参数对塑性带位置形态和宽度等特征的影响,进一步得知塑性带范围变化的同时对边坡破坏时的滑动形状也有一定的影响;而且塑性带的触发时间、宽度与土样的粒径相关,颗粒粒径越小,塑性带的触发时间越早,测量所得的塑性带宽度越小。(3)结合极限平衡严密解法和有限元强度折减法开展了对塑性带数值模拟的对比研究,以土体极限承载力和临界滑裂面作为边坡稳定性参考的依据,分析了处于塑性带上的土体极限承载力和临界滑裂面与塑性带之间的内在联系,通过对比分析,所获得的塑性带内外土体极限承载力的差异和临界滑裂面的位置,揭示了塑性带的变化对于边坡的稳定性起到一定程度的控制作用,并且分析所得滑动并不是发生在一个面上的,而是具有一定厚度的,这与试验所观察到的现象正好相符,从侧面说明了塑性带对边坡的稳定性具有重大意义。
[Abstract]:The process of instability and failure of soil is closely related to the expansion of plastic zone. Numerical simulation and Experimental Research on plastic zone expansion will be helpful to promote the understanding and description of progressive failure of soil slope. The research on this aspect will have important significance and influence on further deeply revealing the process of slope instability. This paper is aimed at the coarse soil slope. The model test and numerical simulation of the development and change of the plastic zone in the soil under the limit state are carried out to study the instability law of the coarse grained soil slope and analyze the stability of the slope on this basis. The conclusions are as follows: (1) the development process of the plastic zone in the coarse grained soil slope is carried out by the self-made model groove. During the test, the real time record of the whole slip form and the displacement of the key point in the limit state is recorded, and the stress, strain and the width of the plastic zone are monitored and collected effectively by the means of preembedding stress box and implanting special wire. This is to reveal some of the characteristics of the plastic zone, that is, the development process of the plastic zone is progressive, and its development begins before the peak of the stress-strain curve, and it is formed after the peak value. At the same time, the sliding form of the slope is a mixed failure mode which is combined with the straight line and the arc section. (2) the effect of the plastic deformation. The related parameters of the sexual zone were studied. The influence of soil cohesive force, internal friction angle, heavy soil mass and the change of particle size on the width and position of the plastic zone was analyzed by combining the test and finite element analysis. The influence of the strength parameters of the soil on the shape and width of the plastic zone was obtained. The change of the plastic zone range also has a certain influence on the sliding shape of the slope, and the trigger time and width of the plastic belt are related to the particle size of the soil. The smaller the particle size is, the earlier the trigger time of the plastic zone is, the smaller the width of the plastic zone is obtained. (3) the closing limit equilibrium method and the finite element strength reduction method are opened. A comparative study of the numerical simulation of the plastic zone is developed. The ultimate bearing capacity and the critical sliding surface of the soil are used as a reference for the stability of the slope. The ultimate bearing capacity of the soil on the plastic zone and the internal relation between the critical slip surface and the plastic zone are analyzed. The ultimate bearing capacity of the soil and the plastic zone is obtained by comparison and analysis. The difference and the position of the critical slip surface reveal that the change of the plastic zone has a certain degree of control on the stability of the slope, and the analysis of the slipping is not on the one surface, but has a certain thickness, which coincides with the phenomenon observed in the experiment, and shows the stability of the plastic zone to the slope from the side. It is of great significance.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU43

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