现代建筑结构基础破坏形式研究及处理措施

发布时间：2018-06-07 12:49

本文选题：填海造陆 + 渗流破坏　；参考：《天津大学》2014年硕士论文

【摘要】：现代建筑结构基础的破坏通常有以下两种形式,其一是建筑结构基础受到上部结构长期持续载荷作用发生沉降或者产生过大的沉降差,从而致使上部结构严重沉陷和倾斜从而丧失使用价值;其二是由于结构基础受到远大于其所能承载的极限而发生破坏。由于结构基础破坏形式的复杂性,如何精确的进行破坏过程的数值模拟以及选取最合适的处理措施是一个需要不断完善的过程。本文在某填海造陆人工岛工程的施工过程中分别考虑了可能存在的不同种类结构基础破坏的形式,主要研究以下三个内容：(1)渗透破坏问题是水利工程地基需要着重考虑的问题。本文选取某填海造陆人工岛工程(内设内河景观工程)的防渗问题进行有限元分析研究。没有采取防渗措施时,该工程在内河与外海地理位置相近的地方出现远大于允许的渗透坡降值,极可能发生渗透破坏,甚至殃及岛上的建筑物。由于渗透损失,内河水位下降的十分迅速,导致内河水位不足以满足观光船只的航行。本文选取最不利工况下渗透坡降大于允许最大坡降位置作为主要防渗体布置位置,然后进行设计论证分析。结果表明,优化防渗措施后,有效的较低了渗透坡降值,并且使内河水位可以维持正常航行的时间得到加长,达到能够安全、稳定运行的目的。(2)人工岛内软土地基,岛上建筑物多采用灌注桩做基础。由于灌注桩侧泥皮的存在,灌注桩与土相接触的模式变为桩、泥皮和土接触的模式,由于泥皮的软化作用,降低了单桩承载力,从而形成泥皮缺陷桩。本文利用有限元法分析了泥皮对灌注桩承载力的影响,并且证明基于后注浆施工工艺对改善泥皮桩承载性状的可行性和有效性。(3)岛上高层建筑物在经处理的软土地基上,基础沉降变形直接关系到上部结构的安全。因此施工过程中要在第一层布置多个沉降观测点,随着楼层的不断加高,实时监测。基础沉降是一个复杂的非线性、动态几何变形过程,各沉降观测点间必有很强的相关性。基于李代数的方法从李群的角度有效的解决了各沉降监测点间的相关性问题。本文以岛上一高层建筑物为例,用李群算法同时对多个监测点的沉降进行动态分析和整体性预测,证明了基于李代数的群测点预测算法在预测建筑结构基础沉降方面的可行性和高效性。
[Abstract]:There are usually two kinds of damage to the foundation of modern building. One is that the foundation of the building is subjected to the long-term continuous load of the superstructure, which results in settlement or excessive settlement difference. Therefore, the superstructure is seriously sunk and inclined, thus losing its use value, and the second is that the foundation of the structure is destroyed because it is far greater than the limit it can carry. Due to the complexity of structural foundation failure, how to simulate the failure process accurately and how to select the most appropriate treatment measures is a process that needs to be improved continuously. In this paper, in the construction process of a reclaimed land artificial island project, the possible forms of different kinds of structural foundation failure are considered separately, and the following three contents: 1: 1) seepage failure is the important problem to be considered in the foundation of water conservancy project. In this paper, the seepage control problem of an artificial island reclamation project is studied by finite element method. In the absence of seepage prevention measures, the project is far larger than the allowable seepage slope value in places close to the inland river and offshore, which is likely to cause seepage damage, even to the buildings on the island. Due to the loss of infiltration, the water level of the inland river falls very rapidly, which leads to the water level of the inland river being insufficient to satisfy the navigation of the sightseeing ships. In this paper, the location of seepage gradient larger than the allowable maximum slope gradient is selected as the main anti-seepage body location under the most unfavorable working conditions, and then the design analysis is carried out. The results show that, after optimizing the anti-seepage measures, the seepage slope value is effectively lowered, and the water level of the inland river can be maintained for a longer period of normal navigation, so as to achieve the purpose of safe and stable operation of the soft soil foundation in the artificial island. Most buildings on the island are based on cast-in-place piles. Because of the existence of the mud crust on the side of the cast-in-place pile, the mode of contact between the cast-in-place pile and the soil becomes a pile, and the mode of contact between the mud and the soil decreases the bearing capacity of the single pile because of the softening of the mud-skin, resulting in the formation of the mud-skin defective pile. In this paper, the influence of mud skin on the bearing capacity of cast-in-place pile is analyzed by using finite element method, and it is proved that based on the feasibility and effectiveness of post-grouting construction technology to improve the bearing behavior of mud-sheathed pile, the high-rise building on the island is on the treated soft soil foundation. The settlement deformation of foundation is directly related to the safety of superstructure. Therefore, multiple settlement observation points should be arranged on the first floor during construction. The settlement of foundation is a complex nonlinear, dynamic geometric deformation process, and there must be a strong correlation among the settlement observation points. The method based on lie algebra can effectively solve the problem of correlation between settlement monitoring points from the point of view of Li Qun. In this paper, a high-rise building on the island is taken as an example. The dynamic analysis and integral prediction of the settlement of multiple monitoring points are carried out by using the Li Qun algorithm at the same time. It is proved that the prediction algorithm of group measuring points based on lie algebra is feasible and efficient in predicting foundation settlement of building structure.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU470

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