高面板堆石坝挤压边墙的破碎机制研究

发布时间：2019-01-26 07:44

【摘要】：随着面板堆石坝的不断发展,挤压边墙施工技术在未来高面板堆石坝工程中被广泛应用已经成为一种趋势。作为混凝土面板的基础结构,挤压边墙的应力变形性态无疑将成为影响面板应力状态的一个关键因素。然而,目前工程界对于挤压边墙破碎问题及其应力变形性态的认识还停留在定性推测阶段,导致在对大坝进行应力变形数值模拟计算时一般都将挤压边墙及其应力变形性态按极端情况来进行近似模拟。因此,为提高高面板堆石坝应力变形数值模拟分析的精细度,深入开展挤压边墙的破碎机制研究是十分必要的。本文针对引起挤压边墙破碎的法向和顺坡向压力荷载作用这两种主要荷载因素,运用试验方法,进行了挤压边墙的破碎机制研究。首先,结合工程实际,进行了挤压边墙混凝土试件材料及结构模拟方法分析,包括配合比设计、试件模具设计、试件制作方法选择,提出了能够准确模拟挤压边墙的结构特征和受力状态的面板—挤压边墙—垫层料模型试件制作方法;其次,运用大型粗粒土动静三轴仪,针对不同配合比、不同搭接长度的面板—挤压边墙—垫层料模型试件,在不同围压条件下,分别进行了法向荷载及顺坡向压力荷载作用下的挤压边墙压裂破碎机理试验,获得了在法向荷载及顺坡向压力荷载作用下挤压边墙压裂破碎的演变规律及其裂缝的分布和变化规律,试验结果表明:水灰比越大、围压越小、搭接长度越小时,裂缝出现的越早,挤压边墙的裂缝最早出现在搭接部位,并且逐步向厚度较大的中间部位发展,所有裂缝大致平行,方向近似垂直面板;在法向压力荷载作用下,挤压边墙的抗压强度与水灰比和围压有关,与搭接长度无关,随着水灰比减小或者围压增大,挤压边墙的抗压强度增大;在顺坡向压力荷载作用下,挤压边墙的最终破坏与挤压边墙的水灰比、搭接长度以及围压均无关。本文运用试验手段研究高面板堆石坝挤压边墙的破碎机制,所得试验结果对面板堆石坝的设计具有一定的参考价值。
[Abstract]:With the continuous development of face rockfill dam, it has become a trend that the construction technology of extruded side wall is widely used in the future high face rockfill dam project. As the foundation structure of concrete slab, the stress and deformation behavior of extruded side wall will undoubtedly become a key factor to affect the stress state of slab. However, at present, the understanding of the crushing problem of extruded sidewall and its stress-deformation behavior in engineering circles is still in the stage of qualitative conjecture. Therefore, in the numerical simulation of the stress and deformation of the dam, the extrusion side wall and its stress and deformation behavior are generally simulated according to extreme conditions. Therefore, in order to improve the fineness of numerical simulation analysis of stress and deformation of high face rockfill dam, it is necessary to deeply study the crushing mechanism of extruded sidewall. In this paper, the crushing mechanism of extruded sidewall is studied by means of experimental method, aiming at the two main load factors, normal and downhill pressure load, which cause the crushing of extruded sidewall. First of all, combined with the engineering practice, the material and structure simulation method of extruded side wall concrete specimen are analyzed, including mix ratio design, test die design, sample making method selection. In this paper, a method of making the model specimens of panel, extruded wall and cushion material, which can accurately simulate the structural characteristics and stress state of the extruded side wall, is presented. Secondly, the large coarse grained soil dynamic and dynamic triaxial apparatus is used to test the model specimens of panel, extruded sidewall and cushion material with different mixing ratio and different lap length, under different confining pressure conditions, Experiments on fracturing mechanism of extruded side wall under normal load and along slope pressure were carried out respectively. The evolution law of fracturing breakage and the distribution and variation of fracture under normal load and along slope pressure are obtained. The experimental results show that the larger the water-cement ratio, the smaller the confining pressure and the smaller the lap length. The earlier the cracks appear, the earliest cracks of the extruded side wall appear in the lap position, and gradually develop to the thick middle part, all the cracks are approximately parallel, the direction is similar to the vertical face; Under the normal pressure load, the compressive strength of the extruded side wall is related to the water-cement ratio and the confining pressure, but not to the lap length. With the decrease of the water-cement ratio or the increase of the confining pressure, the compressive strength of the extruded side wall increases. The ultimate failure of the extruded side wall is independent of the water-cement ratio, the lap length and the confining pressure. In this paper, the crushing mechanism of extruded sidewall of high face rockfill dam is studied by means of test, and the experimental results are of certain reference value for the design of face rockfill dam.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV641.43

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