【作者】 陈杨；

【导师】 蒋树屏；

【作者基本信息】 重庆交通大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 隧道及地下工程中围岩及支护结构的稳定性问题一直以来都是隧道领域所研究的热门课题,但是目前研究只是停留在原有的纯技术层面,而从风险分析角度出发对隧道围岩及支护结构稳定性的分析尚未开展。为了实现隧道工程的技术、经济及安全的均衡和最优化。本文结合白云隧道工程,利用风险管理理论对隧道结构稳定性问题进行了分析研究,论文主要研究内容及结果如下:(1)从可靠度理论出发,对围岩及支护结构稳定性进行了定量的可靠度分析。一是从围岩变形角度出发,建立了基于变形过大的围岩及支护结构刚度失稳极限状态方程,二是从锚杆受力角度出发,建立了基于锚杆承受轴力过大的围岩及支护结构强度失稳极限状态方程。考虑了岩土和支护参数的变异性,通过蒙特卡罗有限元方法计算,获取了围岩及支护结构在各个开挖工况下的失稳概率。(2)首先建立隧道初期支护结构稳定极限状态的功能函数,然后讨论相关随机变量的变异性,最后结合白云隧道ZK42+ 330断面监测的情况,利用风险分析软件@RISK,详细讨论了如何通过监测数据来判定断面范围内围岩及支护结构的失稳概率。(3)在分析多个隧道塌方案例的基础上,结合隧道工程设计施工特点,编制了公路隧道围岩及支护结构失稳的事故树,通过专家调研方法获取事故树中基本事件发生的概率,并引入模糊集的概念,以模糊失效概率代替基本事件的失效概率,用三角形模糊数代替确定性发生概率,同时结合第三、四章的计算结果,作为模糊事故树中条件事件发生的概率,进行事故树的模糊运算,得到了顶事件(围岩及支护结构失稳)的模糊失效概率,并进行基本事件的重要度分析,确定了减小隧道围岩及支护结构失稳概率的有效措施。(4)按照压力拱理论和既有隧道工程事故中各级围岩塌方几何参数的统计以及塌方后所采取的工程措施来确定塌方事故发生后隧道工程所遭受的风险损失,并结合先前围岩及支护结构失稳概率的研究,得到了相应的风险情况。更多还原

【Abstract】 The stability of the surrounding rock and supporting structure has always been the topical issue for the tunnelling and underground engineering, but the present study is only on the purely technical level, the study based on risk analysis has not yet been undertaken. In order to make the technical, economic and safety balanced and optimized , this paper discusses how to study the stability proplem of the surrounding rock and supporting structure according to risk management theory at the Baiyun tunnel project,some main works and results are as follows:(1) The stability of surrounding rock and supporting structure is quantificationally analyzed by reliability theory. Firstly, from the perspective of deformation of surrounding rock, a stiffness limit state equation is set up to judge the stability of surrounding rock and supporting structure. Secondly, from the perspective of axial force the bolts bear, a strength limit state equation is set up to judge the stability of surrounding rock and supporting structure. Considering the variability of parameters of rock and supporting structure, through the Monte-Carlo finite element analysis, instability probabilities of the surrounding rock and supporting are gotten at every excavation step.(2) Firstly, the limit state function about the stability of primary supporting structural is established, and then the variabilities of stochastic variable parameters are studied;with monitoring datas at Section ZK42 +330 of Baiyun tunnel, risk analysis was carried out by @ RISK which is a risk software, and we discussed in detail how to determine the instability probability of supporting structure through these datas.(3) Considering a number of tunnel collapse cases and features of design and construction, fault tree about stability of the surrounding rock and supporting structure is prepared.Through expert research ,the probabilities of basic events are gotten;the concept of fuzzy sets is introduced and the probabilities of basic events are replaced by the fuzzy probabilities, with triangular fuzzy uncertainty probability as a substitute;The analysis results of the third and forth chapters are deemed to the conditions probabilities of the fault tree, and then the fault tree fuzzy operations are done, so fuzzy failure probabilities of the top event are gotten. All the basic events affecting the occurrence probability of the top event are vertified by a sensitivity analysis, so we can make sure the effective measures to reduce the instability probability of the surrounding rock and supporting structure.(4) According to the“pressure arch theory”and the statistics of geometrical parameters of the excisting collapse accidents, as well as engineering measures taken after the collapses, then the direct economic losses suffered can be canculated, combined with previous studies of instability probabilities, then we can get the risk.更多还原