【作者】 鲁文斌；

【导师】 傅鹤林； 伍毅敏；

【作者基本信息】 中南大学 ， 交通运输工程， 2013， 博士

【摘要】 隧道初期支护在施工阶段出现失效而导致坍塌的事故时有发生,经常造成人员被困甚至伤亡。实际支护结构的几何形态及围岩压力与理论值存在较大偏差,这是造成初期支护在施工期失效坍塌的重要原因。因此,采用实测的几何形态参数和全断面实测围岩压力进行异形支护结构的分析和评价,是识别和预防初期支护施工期失效的重要途径。论文结合江西省交通科技重点项目“异形支护结构围岩压力在线监测与评价技术”(项目编号：2009-21),在实体工程初期支护几何形态和围岩压力实测统计分析的基础上,对异形支护结构的力学特性进行了数值模拟分析,研究开发了全断面围岩压力在线监测系统,以此为手段建立了异形支护结构的施工期可靠性分析和围岩压力安全性预测的方法。主要研究内容及成果如下：(1)通过实体工程的测量和统计分析,分别研究了隧道支护结构环向变异、纵向变异以及实测围岩压力的量值及统计规律。结果表明：支护结构环向几何变异幅度很大,影响因素复杂,随机概率模型及参数不稳定；支护结构纵向几何变异主要取决于施工管理水平,符合正态分布；约束状态下的实测围岩压力规律性差,量值及分布均与理论值存在较大偏差。(2)采用ANSYS有限元软件,对隧道支护结构环向变异和纵向变异的力学效应进行了对比分析,揭示了不同条件下异形支护结构的受力特性。重要结论包括：使支护结构拱部变薄、边墙变厚的变异对结构承载有利,反之不利,实践中应控制拱顶至拱肩段的超挖,限制边墙段的欠挖；隧道拱肩段的超欠挖都对支护结构的承载有十分不利的影响,应特别注意控制；对于偏压隧道,大荷载一侧拱顶至拱肩的超挖对承载不利,应注意控制,边墙段(特别是小荷载侧)的适度超挖对结构承载有利。(3)针对用压力盒测量围岩压力的不足,基于山形应变传感器研制了一种分布式压力传感器,构建了隧道全断面围岩压力在线监测系统,首次实现了工程意义上的全断面围岩压力实时监测和评价。该系统的主要性能指标为：压力信息点的环向间距小于20cm；单洞隧道300m施工区段内布设15个监测断面时,巡检周期小于5分钟。(4)基于实测支护结构的几何形态参数和全断面围岩压力,建立了异形支护结构的变截面双铰拱力学模型,推导了截面内力的计算公式,编写了计算程序,实现了异形支护结构全断面围岩压力的快速分析。(5)建立了仅依赖全断面围岩压力随机性的异形支护结构施工期可靠度理论,采用蒙特卡罗随机抽样方法实现了施工期可靠性的快速分析；基于灰色系统理论,建立了全断面各压力信息点的压力预测模型,提出了围岩压力安全性预测的方法。图57幅,表48个,参考文献139篇更多还原

【Abstract】 The accident of supporting structure become invalid and lead to failure often happens during tunnel construction, sometime will caused injuries and deaths. There exist big difference between supporting structure geometry and earth pressure theory, and this is the main reason why supporting structure become invalid. On the base of situ monitor and evaluation technology for surrounding rock pressure caused by overbreak or underbreak during tunnel construction is an important approach to distinguish and forecast supporting structure become invalid. Combined with important communication project of Jiangxi province" situ monitor and evaluation technology for earth pressure of surrounding rockmass caused by overbreak or underbreak of dysmorphism tunnel structure"(No.:2009-21), and on the base of situ monitor and statistics; census; numerical statement; vital statistics: census; vital statistics, a on line monitor system of whole section earth pressure has been developed, and then an reliability analysis and safety forecast method for dysmorphism tunnel structure has been established in this paper. The main content includes followings:(1) On the base of situ monitor and statistics, the regular pattern of circumferential, longitudinal deformation profile and earth pressure of dysmorphism tunnel structure has been disclosed. The results show that, range of circumferential deformation is big, and influence factors are complicated, and random probability model is instable; under restrict conditions, the regular pattern of situ earth pressure becomes bad, compared with theoretical value, the monitor value has big difference.(2) The regular pattern of circumferential, longitudinal deformation profile has been disclosed with ANSYS. The conclusion has been gained, i.e. if the are area become thinner, and side wall become thicker, the mechanical performance will be better; during construction, the overbreak in the area between arc roof and spandrel and the underbreak in the area of side wall should be restricted.(3) According to mountain deformation sensor, an new pressure dispersing sensor has been made to monitor the earth pressure, and an new on line monitoring system of earth pressure of whole tunnel section has been established, this has realized the earth pressure of whole tunnel section will be monitored in the whole time. The index of this system are:the circular distance among data sites smaller than20cm, in single300m tunnel, the number of the monitor sections is15,inspection cycle is shorter than5minutes.(4) On the base of geometry parameters of supporting structures and earth pressure of whole section, the two hinged arch mechanics model of dysmorphism supporting structure has been established, and section inner stress calculation formula has been inferred, the calculation program has been compiled. The surrounding rock pressure of dysmorphism supporting structure will be fast monitored.(5) Combined with Monte Carlo random theory, reliability model to analyze the surrounding rock pressure of dysmorphism supporting structure has been established. On the base of Grey system, forecast model of surrounding rock pressure in dysmorphism supporting structure has been put forward, and an effective approach to predict the rockmass safety has been formed.更多还原