路湾隧道施工阶段安全风险评估及数值模拟

发布时间：2018-08-10 18:14

【摘要】：十七大以来，随着我国社会经济、文化的快速发展，无论是道路交通还是铁路交通已经无法满足其基本要求。加快偏远地区交通建设特别是山区交通建设，拉动当地经济发展，已成为政府工作的重点。由于隧道工程的施工技术要求高，工序繁琐，不确定因素多，管理还不够完善，在施工中面临着各种各样的已知的或者未知的风险，这些风险时刻威胁着施工人员、机械，严重的使整个工程都陷入瘫痪。所以，对隧道进行风险评估管理不论对人员机械的安全，还是控制成本；保证工期和施工质量方面都具有重大的意义。本文以大跨偏压浅埋路湾隧道为研究背景，以专家调查法、故障树分析法、数值分析为理论基础，对隧道施工阶段安全风险管理和出洞施工进行了分析研究。研究内容及取得到主要结论有：通过学习风险评估的国内外发展近况，研究了公路隧道施工安全风险的内涵、风险评估的流程、方法和指标体系，建立公路隧道施工安全风险管理体系。采用调查表与专家咨询法，辨识出了路湾隧道施工安全的主要风险因素，得出了路湾隧道施工存在大变形风险、洞口失稳风险、物体打击风险、交通事故风险等十一个安全风险。利用故障树分析法建立评估模型；利用专家咨询法得到各个基本风险因素的概率；基于故障树算法计算出各个风险事件发生的概率并且进行了重要性排序；发现路湾隧道在施工过程中，不良地质造成的大变形风险和洞口失稳风险发生的概率是最大，并对每个风险事件进行了定性分析并给出了应对措施。针对大变形、洞口失稳风险，利用FLAC3D软件对大跨偏压浅埋路湾隧道出洞技术进行分析研究，得出了双侧壁导坑法在隧道出洞过程中围岩的应力应变和初期支护的内力等的变化规律，分析发现施工中右导坑和上台阶的开挖对围岩扰动最为明显，竖向位移、水平位移和地表沉降的变化量较大，大变形风险增大；特别是靠近洞口时，上台阶的开挖对拱顶沉降影响明显，极有可能发生洞口失稳风险，，所以施工中应加强监控量测，提高各个环节的施工质量；左导坑和下台阶施作时拱脚部位容易出现应力集中，应加强锁脚锚杆的施工质量。本文的研究成果对大跨偏压浅埋隧道施工阶段安全风险管理及出洞施工技术的研究具有参考和应用价值。
[Abstract]:Since the 17th National Congress, with the rapid development of social economy and culture, both road traffic and railway traffic have been unable to meet its basic requirements. Speeding up traffic construction in remote areas, especially in mountainous areas, and stimulating local economic development have become the focus of government work. Because of the high technical requirements, complicated working procedures, many uncertain factors and imperfect management, tunnel engineering is faced with a variety of known or unknown risks, which threaten the construction personnel and machinery at all times. The whole project was seriously paralyzed. Therefore, the risk assessment management of tunnel is of great significance not only to the safety of personnel and machinery, but also to the control of cost, the guarantee of construction time and the quality of construction. In this paper, based on the research background of long span bias voltage and shallow buried road bay tunnel, based on expert investigation, fault tree analysis and numerical analysis, the safety risk management and tunnel construction in tunnel construction stage are analyzed and studied. The research contents and main conclusions are as follows: through studying the recent development of risk assessment at home and abroad, the connotation, process, method and index system of highway tunnel construction safety risk are studied. Establish the safety risk management system of highway tunnel construction. By means of questionnaire and expert consultation, the main risk factors for the construction safety of Luwan Tunnel are identified, and the risk of large deformation, the risk of instability at the entrance of the tunnel and the risk of object striking in the construction of Luwan Tunnel are obtained. Traffic accident risk and 11 safety risks. The evaluation model is established by using fault tree analysis, the probability of each basic risk factor is obtained by using expert consultation method, the probability of each risk event is calculated based on fault tree algorithm and the importance ranking is carried out. It is found that the probability of large deformation risk and hole instability risk caused by bad geology is the greatest in the construction process of Luwan tunnel. The qualitative analysis of each risk event is made and the countermeasures are given. Aiming at the risk of large deformation and instability of tunnel mouth, this paper analyzes and studies the tunnel exit technology of shallow buried road bay tunnel with long span bias pressure by using FLAC3D software. The variation law of stress and strain of surrounding rock and the internal force of initial support are obtained by double sidewall guide pit method in the course of tunnel exit. It is found that the excavation of right guide pit and upper step in construction has the most obvious disturbance to surrounding rock and vertical displacement. The variation of horizontal displacement and surface subsidence is larger, and the risk of large deformation is increased. Especially, when the excavation of the upper steps is near the hole, the influence on the settlement of the arch is obvious, which is very likely to occur the risk of instability of the hole, so the monitoring and measurement should be strengthened in the construction. In order to improve the construction quality of each link, the stress concentration is easy to appear in the arch foot when the left guide pit and the lower steps are being worked on, so the construction quality of the locking foot anchor rod should be strengthened. The research results of this paper have reference and application value for the study of safety risk management and construction technology of long span bias and shallow buried tunnel during construction stage.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.1

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