【作者】 王宁；

【导师】 王志杰；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2017， 硕士

【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。更多还原

【Abstract】 The national traffic network has been developing continuously,and the dense transportation network has brought about a large number of mountain tunnels close construction phenomenon.Tunnel near the railway,pile,close to the existing tunnel situation has occurred.Due to the complex structure of the tunnel,the uncertain soil,excavation will disturb the surrounding soil,and then have an impact on the existing structure,even will lead to the occurrence of disasters.At the same time,the tunneling problem has always been a hot topic in the tunnel engineering field.This paper is based on the newly built tunnel project on both sides of the existing tunnels of Pu Mei Railway.For the actual situation of the project,we study on the adjacent project by the way of the data research,and numerical simulation.The main contents and achievements of this paper are as follows:(1)This paper summarizes the relevant theories of adjacent construction at home and abroad,and studies the tunnel excavation with different mechanical models and different stress analysis methods under different conditions.We proposes the concept of equivalent diameter of multi-tunnel and revise the geometric adjacent degree to adapt to multiple tunnels adjacent to a structure of the situation at the same time,Which provides theoretical support for the adjacent tunneling of double newly built tunnels.(2)Analysis of recent engineering design information,this paper use the finite element software MIDAS GTS NX to analyze the actual situation of the adjacent project,and establish the adjacent form of different structures and different excavation order models.The excavation mechanics behavior is studied by means of the stress of the surrounding rock,the displacement and the internal force of the structure.According to different changes in the law,the optimal excavation order is founded,which provides some technical support for the construction.(3)We summarize six kinds of criteria of adjacent influence degree,and determine the structural displacement criterion and the existing structural reliability criterion according to the actual situation,then carry out the study of adjacent partition.The influence subzone,based on the analysis of the influence of different distance on the existing structures(50 kinds of conditions)and combined with the identified structural displacement and structural reliability criteria,is determined according to the adjacent degree formula.(4)By summarizing the relevant information and the related engineering examples,the dissertation defines the processes to solve the adjacent construction problems.It is suggested that different construction countermeasures should be adopted for different adjacent impacts.We propose a set of assessment models,including the improvement coefficient of the various measures and the difficulty of funds,technology and construction.The coefficient of use is evaluated,and according to this coefficient,the construction strategy is selected,which will play a supporting role in the follow-up construction selection.更多还原