受冲击的饱和砂土产生裂缝和通道的实验研究

IMECH-IR > 力学所知识产出(1956-2008)

	受冲击的饱和砂土产生裂缝和通道的实验研究
	彭福骄
导师	郑哲敏 ; 谈庆明
	1999
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位类别	硕士
学位专业	工程力学
关键词	饱和砂土冲击渗流水平裂缝纵向通道液化指数 Saturated Sand Impact Permeability Crack Drainage Pathway Liquefaction Index
英文摘要	本文首先对饱和砂土在动载荷下的液化、密实和结构破坏等方面做了文献综述，同时也叙述了化工冶金中的液固流态化的有关情况。本文探讨了饱和砂土中产生水平裂缝和纵向通道等现象的机理。为此，进行了扁平砂柱的落锤冲击实验和模拟圆柱落锤冲击实验中产生水平裂缝和纵向通道等现象的底部加压实验。扁平砂柱落锤冲击实验的目的是为了更清楚地观察饱和砂土结构破坏和孔隙水流动的情况，观察纵向通道和水平裂缝的产生和发展，以及水平裂缝和纵向通道之间的联系。为了探讨水平裂缝和纵向通道产生的条件和机理，设计和进行了底部加压实验，用来模拟落锤冲击实验的后期变形和渗流效应，测量出现水平裂缝和纵向通道时的超孔隙水压力和平均水流速度，统计分析采用什么样的参数可以表征水平裂缝和纵向通道的出现及其特性，发现液化指数等于1是出现水平裂缝的必要条件。此外，针对含有细砂层的饱和砂土在该层出现水平裂缝的现象，提出了一个简化模型，推导出砂柱的液化指数一维分布，根据液化指数等于1才能出现水平裂缝，能够说明水平裂缝出现的条件和位置。; First, this thesis summarized the present status of study on liquefaction, densification and structural changes in saturated sands upon impact and vibration loading. At the same time, the related aspects about liquid-solid fluidization in chemical engineering were depicted. This research aims at probing into the mechanism of formation of horizontal cracks and longitudinal drainage pathways in saturated sands. Two kinds of the experiments were carried out, i.e. (1) Impact experiments in which a dropping flat cuboid sand column is impacted on the ground; (2) Steady driving experiments in which the driving water pressure is applied the bottom of sand column in order to simulate the late-stage effects in impact experiments. The purpose of the impact experiment is to distinctly observe the structural changes and the seepage of the pore water. Not only the onset and development of horizontal cracks and longitudinal drainage pathways, but also the relation between them was observed. In order to probe into the mechanism of formation of horizontal cracks and longitudinal drainage pathways, the steady driving experiments were carried out to longitudinal drainage pathways, the steady driving experiments were carried out to simulate the late stage phenomena, horizontal cracks and longitudinal drainage pathways, presented in impact experiments. The distributions of exceed pore water pressure and average flow rates of water were measured. Several statistics were analyzed to determine which parameter could best characterize the emergence of horizontal cracks and longitudinal drainage pathways. It was found that "liquefaction index equals 1" is a necessary condition for the onset of horizontal cracks. Furthermore, a simplified model was brought forward to explain the beginning of horizontal cracks. One-dimensional distribution of liquefaction index of the sand column was derived, then the condition and location for the beginning of horizontal cracks have been proposed when several thin layers of fine sand exist in the original sand column.
索取号	29862
语种	中文
文献类型	学位论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/23620
专题	力学所知识产出(1956-2008)
推荐引用方式 GB/T 7714	彭福骄. 受冲击的饱和砂土产生裂缝和通道的实验研究[D]. 北京. 中国科学院研究生院,1999.

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