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京张城际铁路八达岭地下站三洞分离结构优化研究
Structural Optimization of Badaling Underground Station with Cross-section of Three Single Tunnels of Beijing-Zhangjiakou Intercity Railway
【作者】 程伟;
【导师】 贺少辉;
【作者基本信息】 北京交通大学 , 桥梁与隧道工程, 2011, 硕士
【摘要】 京张城际铁路八达岭地下车站拟修建于国家自然保护区八达岭风景区的山体中,是中国首例修建于山体中的深埋城际铁路车站,也是世界上少见的工程。因车站埋深较深、开挖体量很大、结构型式复杂,所以是拟建新京张城际铁路的重点控制性工程。由于到目前为此,还没有类似工程的先例,因此常用的工程类比法不能提供有效的作用,因此有必要对八达岭地下车站的拟采用的结构方案进行研究。本文以新京张城际铁路八达岭地下车站为依托,主要对车站主体结构施工工法与支护参数的优化进行研究。其相关工作和成果有:(1)综述了此类工程具有的特点和难点,以及当前国内外类似工程概况和国内外对类似工程的研究现状,为京张城际铁路八大岭地下车站的施工和支护参数的选取提供借鉴和参考;(2)综合分析了隧道与地下洞室围岩力学的基本理论,隧道与地下洞室在施工时围岩各个部位的力学特性,研究了影响围岩稳定的各种因素。并且对“新奥法”喷锚支护的锚固机理进行了较为详细的阐述。为京张城际铁路八达岭地下站的施工和支护提供了理论基础;(3)研究了当前地下结构优化的内容和方法,为八达岭地下站结构方案优化提供了指导;(4)评价了八达岭地下车站站址区的工程地质条件,运用有限差分FLAC3D程序模拟了车站分离三洞结构方案三台阶法施工的全过程;对两种施工方案下的围岩与支护稳定性进行了较为详细的对比,选出了合适的施工方案,为后面的八达岭地下车站支护参数优化方案的制定打下了基础;(5)首先运用正交试验法,以顶底板相对位移、两帮相对位移为评价指标对结构支护参数中的锚杆长度、锚杆间距、锚杆排距、喷射混凝土层厚度进行了优选;然后运用二次回归正交试验法对优选出的锚杆长度和喷射混凝土层厚度进行了进一步的研究。确定了喷射混凝土厚度和锚杆长度和顶底板相对位移这一指标的关系,并且得出了最优方案,为八达岭地下车站的设计和施工提供科学的理论依据和指导。
【Abstract】 Badaling Underground Station of Beijing-Zhangjiakou Intercity Railway will be built in Badaling mountain where is National Nature Reserve. It’s the first intercity railway example which is constructed in the mountain, also is rare in the world. Badaling underground station is the focus control project of the proposed new Beijing-Zhangjiakou intercity railway because of deep setting depth, large excavating area, as well as the complex structural type. As far as now, there is few similar preliminary projects for reference. As a result, Engineering analogy method can’t provide effective function.So it is necessary to do some research on the proposed structure program.Based on the main structure of Badaling underground station, this thesis will mainly do research on the optimization of the station’s support parameters. The related work and results are as follows:(1) Such projects’ features and difficulties, and overview of similar projects and reserch at home and abroad were briefly summarized. Which provided instruction and reference for design and construction for Badaling underground station;(2) The basic theory of mechanics of the tunnel and underground caverns, and the mechanical properties of the various parts of Tunnels and underground rock in the construction were comprehensively analyzed. Various factors affect the stability of surrounding rock were studied. And anchoring mechanism of anchor supporting in the"New Austrian Tunneling Method" was described in detail. It Provides a theoretical basis for excavation and surpporting of badaling Underground Station of Beijing-Zhangjiakou Intercity Railway.(3) The current contents and methods of structural optimization for underground structures were studied,which provide guidance for Badaling underground station(4) Badaling underground station’s geological conditions were evaluated in this thesis.The finite difference procedure FLAC3D was used to simulate the whole process of three-step excavation method for the independent three tunnels’ structural station;Also This thesis detailedly analyzed stability of surrounding rock and support structure under different excavations, and selected a suitable construction plan.This provided a basis of deciding for the final specific of support parameters optimization of Badaling underground station;(5) The orthogonal testing method was used to choose the more important factors from length of anchor bar, anchor spacing, row spacing and thickness of spray layer,by the evaluation index roof-to-floor relative displacement and two sides relative displacement. Then utilized the Quadratic Regression Test to do further research on length of anchor and thickness of spray layer. And finally determined the relationship between the thickness of sprayed concrete floor, bolt length and the roof-to-floor relative displacement, and made out the optimum scheme. This will provide some scientific theory evidence and guidence for follow-up design and construction of Badaling underground station.