桩基础水闸渗流稳定分析研究

发布时间：2017-12-31 13:12

本文关键词：桩基础水闸渗流稳定分析研究　出处：《兰州交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：做为水工结构中比较常见的多功能建筑物,水闸对我们水利工作者并不陌生,水闸建设历史悠久,结构种类繁多,规模也有大有小。桩基础是一种优良的地基处理方法,适应不良地层的能力强,而且因为混凝土材料具有较低的低渗透性,还可作为防渗结构,具有附加抗渗效果。在天然地基下水闸施工不满足结构稳定条件时,地基处理可利用桩基础稳定性强的优点形成桩基础水闸。跟所有水利建筑一样,对渗流的研究是伴随水利行业发展的其中一部分。渗流是影响结构稳定性的重要因素,渗流计算也是水闸破坏的预防。在大量的水利学者在水闸设计施工过程中,总结了一系列渗流计算和防渗的经典方法,解决了大量的渗流难题。但具体到桩基础水闸中,由于桩土材料性质的差异,桩基在地基中的不连续,也不能单一的视之为防渗体。桩基在提供地基承载能力的同时对渗流场和应力场的影响仍然需要进一步的研究。所以,笔者认为研究桩基础水闸的渗流问题很有必要。本文从介绍渗流计算发展研究现状开始,对目前水闸渗流计算的常见方法以及各自方法的适用性及优缺点逐一罗列,方法显示了对桩基础水闸渗流计算的局限。着重讲述了渗流基本理论,并逐步引入渗流计算的有限元方法,介绍了在水闸应力分析中土体mohr-coulomb模型以及建模时所采用的采用midas GTS软件。通过对桩基础水闸渗流稳定的数值模拟,得到了以下内容:利用渗流有限元计算方法,分别对闸底板布置有桩基础的三汊河口闸以及相同参数下的天然地基水闸进行渗流分析,并对不同水位变化下水闸的水头分布、渗透坡降及流量结果进行比较,结果显示,桩基础的植入会降低水头分布,减小较大水头占整个渗流场的比例,并且会降低水闸的水平渗透坡降,在稳定渗流场中,桩的体积占据与流场中,会降低渗流量。对整个水闸结构产生正的防渗效果。而后笔者对三汊河口闸进行渗流-应力耦合场分析,在竣工期和最高水蓄水位两种工况下的水平和竖向位移成果分析得出,竣工期桩基水闸发生最大竖向位移。闸基在重力作用下偏重心发生倾斜,在水闸结构的带动下周围土体集中朝中部发生位移。在最高蓄水位工况时,位移趋势类似于竣工期,但由于水压力作用,高水位侧发生的水平位移比竣工期大,但受制于扬压力作用,竖向位移较竣工期小。同时,对桩基础水闸的特征部位-闸底板下土层和与桩端的接触土层做了单独的位移分析,结果显示,在竣工期和蓄水期,特征部位的位移与整体位移相协调,呈现竣工期位移大,蓄势期位移小的特点。桩基础是地基处理的一般方法,尤其适用于不良地基,条件允许下,桩基础水闸既能保证结构稳定,也能兼顾结构抗渗。是可以广泛使用的结构类型。
[Abstract]:As a common multifunctional building in hydraulic structure, sluice is no stranger to our water conservancy workers. The construction of sluice has a long history and many kinds of structures. The pile foundation is a good foundation treatment method, which has strong ability to adapt to bad stratum, and because of the low permeability of concrete material, it can also be used as anti-seepage structure. When the construction of sluice under natural foundation does not meet the structural stability conditions, the foundation treatment can take advantage of the strong stability of pile foundation to form pile foundation sluice, just like all water conservancy buildings. The study of seepage is a part of the development of water conservancy industry. Seepage is an important factor affecting the stability of structure. Seepage calculation is also the prevention of sluice damage. In the process of design and construction of sluice, a series of classical methods of seepage calculation and seepage prevention are summarized. A large number of seepage problems have been solved, but in the pile-foundation sluice, the pile foundation is discontinuous in the foundation due to the difference of the property of the pile-soil material. The influence of pile foundation on seepage field and stress field still needs further study while providing bearing capacity of foundation. The author thinks that it is necessary to study the seepage problem of the sluice of pile foundation. The common methods of sluice seepage calculation, their applicability, advantages and disadvantages are listed one by one. The method shows the limitation of seepage calculation for pile foundation sluice, and emphasizes on the basic theory of seepage. The finite element method for seepage calculation is introduced step by step. This paper introduces the mohr-coulomb model of soil mass in sluice stress analysis and the numerical simulation of seepage stability of pile foundation sluice by using midas GTS software. The following contents are obtained: using the seepage finite element method, the seepage analysis is carried out for the sluice with three braided sluices with pile foundation on the bottom plate and the natural foundation sluice with the same parameters. The results of head distribution, seepage gradient and discharge of sluice under different water levels are compared. The results show that the placement of pile foundation will reduce the distribution of water head and decrease the proportion of larger head to the whole seepage field. And it will reduce the horizontal seepage slope of sluice, in the steady seepage field, the volume of pile occupy and flow field. The seepage discharge will be reduced and the anti-seepage effect will be positive for the whole sluice structure. Then the author analyzes the seepage and stress coupling field of the sluice at the three braided river mouth. Through the analysis of horizontal and vertical displacement results under the two working conditions of the completion period and the maximum water storage level, it is concluded that the maximum vertical displacement occurs in the pile foundation sluice during the completion period, and the gravity center of the sluice foundation tilts under the action of gravity. The displacement of soil around the sluice structure is concentrated towards the middle, and the displacement trend is similar to the completion period when the maximum storage water level is working, but the horizontal displacement on the high water level side is larger than the completion period because of the effect of water pressure. However, the vertical displacement is smaller than the completion period due to the action of uplift pressure. At the same time, the displacement analysis of the characteristic part of the sluice under the bottom of the sluice and the contact soil layer between the bottom of the sluice and the end of the pile is made, and the results show that. In the period of completion and storage, the displacement of the characteristic part is in harmony with the whole displacement, showing the characteristics of large displacement in completion period and small displacement in storage period. Pile foundation is a general method of foundation treatment, especially suitable for poor foundation. The pile foundation sluice can not only guarantee the stability of the structure but also give consideration to the impermeability of the structure. It is a widely used type of structure.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV66;TV223.4

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