高速铁路中桥梁群桩基础沉降研究

发布时间：2018-01-21 07:42

本文关键词： 群桩基础沉降计算改进方法有限元蠕变　出处：《武汉理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着我国交通需求量的急速增加，大力发展高速铁路已成为我国当前的一项重大任务。高速铁路对基础处沉降控制非常严格，而我国高速铁路中桥梁路段占了相当大的比重，因此桥梁群桩基础的沉降计算的研究对高铁的建设有着重大的意义。它不仅是桥梁设计与施工的重要参考依据，同时也是确保高铁安全运营的重要指标。传统的群桩沉降计算方法很多，但这些理论大都不够精确，主要是因为它们存在以下一些问题：（1）未考虑群桩侧面土的总剪切力的影响，对深、浅基础采取一样的方法计算；（2）未考虑桩间土的压缩变形，与实际情况不相符合；（3）未考虑地基的蠕变变形引起的沉降，使得计算结果不准确。本文针对以上问题，在以成渝高铁中邓家湾双线大桥5号和21号桥墩群桩基础实际测量数据为参考的基础上，做了如下工作：对传统群桩测量方法中的等代墩基法进行了修正，在计算中不仅考虑到了桩长范围内侧面土层的总抗剪力，同时也考虑了该范围内土的压缩量，得到了改进等代墩基法，并用以计算群桩基础沉降；然后利用ANSYS有限元软件中接触模型对群桩基础进行了模拟；最后，在ANSYS模型计算结果的基础上，对地基的蠕变沉降予以建模计算，并得出了考虑蠕变沉降的桩基沉降结果。研究结果表明：（1）改进的等代墩基法相对于传统的等代墩基法，考虑更加全面，能更准确的计算出群桩基础沉降，但是仍与实测数据存在一定的差异；（2）未考虑地基蠕变变形的ANSYS建模方法能较好模拟群桩沉降，，计算结果与实测值较为接近，但不够精确，说明在准确计算桥梁群桩基础沉降时，需对地基的蠕变变形予以考虑；（3）考虑地基蠕变变形的ANSYS建模能更准确模拟群桩沉降计算，其计算精度能够达到95%左右。（4）改进等待墩基法及ANSYS模拟群桩沉降计算方法对工程计算有一定的参考价值。
[Abstract]:With the rapid increase of traffic demand in China, the development of high-speed railway has become a major task at present in China. High-speed railway is very strict to control the settlement of the foundation. In our country, the bridge section accounts for a large proportion of the high-speed railway, so the settlement calculation of bridge pile group foundation is of great significance to the construction of high-speed rail, it is not only an important reference for bridge design and construction. At the same time, it is also an important index to ensure the safe operation of high-speed railway. There are many traditional calculation methods of pile group settlement, but most of these theories are not accurate enough. The main reason is that they have the following problems: 1) not taking into account the influence of the total shear force of the soil on the side of the pile group, and using the same method to calculate the depth and shallow foundation; (2) the compression deformation of soil between piles is not in accordance with the actual situation; 3) the settlement caused by creep deformation of foundation is not taken into account, which makes the calculation result inaccurate. In view of the above problems, based on the actual survey data of pile group foundation of No. 5 and 21 piers of Dengjiawan double-track bridge in Chengdu-Chongqing high-speed railway, the paper takes as the reference data. The following work has been done: the method of equivalent pier foundation in the traditional pile group survey method has been modified. In the calculation, not only the total shear resistance of the lateral soil layer in the pile length range is taken into account, but also the compressibility of the soil in this range is considered. The improved equal-substitute pier foundation method is obtained and used to calculate the settlement of pile group foundation. Then the contact model of ANSYS finite element software is used to simulate the pile group foundation. Finally, based on the results of ANSYS model, the creep settlement of foundation is modeled and calculated, and the settlement results of pile foundation considering creep settlement are obtained. The results show that the improved method is more comprehensive and can calculate the settlement of pile group foundation more accurately than the traditional method, but there is still some difference with the measured data. 2) the ANSYS modeling method without considering the creep deformation of foundation can simulate the settlement of pile group better, and the calculated result is close to the measured value, but it is not accurate enough, which shows that the settlement of pile group foundation of bridge is calculated accurately. The creep deformation of the foundation should be considered. (3) the ANSYS model considering the creep deformation of foundation can simulate the settlement of pile group more accurately. The accuracy of the method can reach about 95%) the improved method of waiting pier foundation and the method of simulating pile group settlement by ANSYS have certain reference value for engineering calculation.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.15

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