既有隧道两侧新建近接隧道施工力学行为及影响分区研究

发布时间：2018-06-02 13:41

本文选题：近接施工 + 力学行为　；参考：《西南交通大学》2017年硕士论文

【摘要】：国家交通路网不断发展,交通网的密集发展带来了大量山岭隧道近接施工现象,隧道近接铁路、桩基、近接既有隧道以及其他构筑物情况时有发生。由于近接形式多样,岩土体存在不确定性,开挖中势必会扰动周边岩土体,继而对既有结构物产生影响,严重时会导致事故灾害的发生。同时隧道近接问题一直以来都是隧道工程界研究的热门话题,合理确定近接问题研究流程,准确分析近接施工相关对策,对近接施工实际问题的解决有重要意义。本文以浦梅铁路既有隧道两侧新建近接隧道工程为依托,针对工程实际情况,从资料调研、数值模拟方面,对近接工程进行研究。本文主要研究内容及成果如下:(1)总结了国内外学者关于近接施工相关成果,研究不同情况下,采用不同力学模型及不同受力分析方法对隧道开挖进行模拟。提出多近接隧道结构物综合尺度概念,对几何近接度进行了修正,使其适应多近接隧道同时近接某一结构物情况,为后续对双新建隧道近接既有隧道分区提供了理论支持。(2)分析了近接工程的设计资料,利用有限元软件MIDAS GTS NX对近接工程实际情况进行分析,分别建立了不同结构物近接形式模型。基于围岩应力、既有结构物位移、既有结构物内力三方面,对隧道开挖力学行为进行分析,并依据不同变化规律,得到不同结构形式最优化开挖顺序,对施工提供一定技术支持。(3)总结了六种近接影响分区分度准则,并根据实际情况确定既有结构物位移以及既有结构可靠度两种分区分度准则,数值模拟分析新建两侧隧道不同净距(50种工况)下对既有结构物影响,结合分区分度准则,依据近接影响度表达式,确定近接影响分区。(4)在前人研究的基础上,确定解决近接施工问题相关流程;对不同近接影响分区建议采用不同施工对策,并提出一套评估模型,综合分析各项对策的改善系数以及施工中资金、工期、技术难度程度,得到对策的使用系数,依据此系数对施工对策进行选取,为后续施工选择提供参考。
[Abstract]:With the continuous development of national traffic network, the intensive development of traffic network has brought a large number of mountain tunnel near construction phenomenon, tunnel close to railway, pile foundation, close to existing tunnels and other structures occur from time to time. Due to various forms of proximity and uncertainty of rock and soil, the surrounding rock and soil will inevitably be disturbed during excavation, and then the existing structures will be affected, which will lead to the occurrence of accident disasters when serious. At the same time, the problem of tunnel proximity has always been a hot topic in the field of tunnel engineering. It is of great significance to determine the research flow of the close-in problem and to analyze the relevant countermeasures of the close-in construction accurately, which is of great significance to the solution of the practical problems in the close-joint construction. In this paper, based on the construction of the existing tunnel on both sides of the Pumei Railway, according to the actual situation of the project, from the aspects of data investigation and numerical simulation, the paper studies the near junction project. The main contents and results of this paper are as follows: (1) summarizing the related achievements of scholars at home and abroad, and studying the different mechanical models and different force analysis methods to simulate the tunnel excavation under different conditions. The concept of synthetic scale of multi-close tunnel structure is put forward, and the geometric proximity degree is modified to suit the situation of multi-close tunnel with a structure close to each other at the same time. In this paper, the design data of the adjacent tunnel are analyzed, and the actual situation of the project is analyzed by using the finite element software MIDAS GTS NX. The models of the close connection of different structures were established respectively. Based on the stress of surrounding rock, displacement of structure and internal force of structure, the mechanical behavior of tunnel excavation is analyzed, and the optimal excavation sequence of different structural forms is obtained according to different variation rules. To provide certain technical support to the construction, this paper summarizes six kinds of classification criteria for the influence of close connection, and according to the actual situation, determines the existing structure displacement and the reliability of the existing structure. Numerical simulation is used to analyze the influence on existing structures under 50 working conditions with different net distances). Based on the criterion of classification and the expression of influence degree of close connection, the influence zone of near connection is determined. (4) based on the previous studies, To determine the relevant process to solve the problem of near-connection construction, to propose different construction strategies for different adjacent impact zones, and to put forward a set of evaluation model, comprehensively analyze the improvement coefficient of each countermeasure, as well as the funds, construction period, technical difficulty degree in construction. The use coefficient of the countermeasure is obtained, and the construction countermeasure is selected according to this coefficient, which provides a reference for the subsequent construction selection.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4

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