渗流作用下复合地层盾构隧道施工开挖面稳定性及控制研究

发布时间：2018-03-02 21:48

  本文选题：盾构隧道　切入点：开挖面稳定性　出处：《山东大学》2016年博士论文　论文类型：学位论文

【摘要】：今年来,随着城市建设的快速发展,城市规模不断扩大,城市密集度不断提高,城市交通逐渐恶化,环境污染越发严重,严重制约了经济和社会的进一步发展。为缓解地面交通压力,改善城市交通环境,促进城市的可持续发展,城市建设逐步转变为大力开发地下空间的全新理念,盾构法作为一种较新的施工方式,在城市地下空间的施工中的应用也逐渐增加。但随着盾构技术的发展以及开挖的要求越来越高,所面临的问题也越来越多,施工过程中开挖面稳定性的预测和控制非常困难,极易发生地表沉陷、开挖面突涌水等灾害事故。据不完全统计,我国的北京、上海、广州、南京、深圳等主要城市在地铁盾构隧道建设中均发生过重大开挖面失稳事故,造成了重大的经济损失和人员伤亡。针对地铁建设环境条件复杂、地层敏感性高、控制标准严苛的特点,如何有效的预测和控制开挖面稳定性,成为盾构隧道施工的核心问题之一。本文以地铁隧道土压平衡盾构施工为主要研究对象,依托济南地铁盾构隧道工程,通过室内实验、理论分析、数值计算、模型试验和现场试验等手段,深入研究复合地层盾构施工开挖面失稳机理、渗流作用下开挖面失稳破坏灾变演化特性以及失稳防治技术体系,取得了具有一定理论价值和工程意义的研究成果,主要包括：(1)总结提出了盾构施工工法选型流程,从地层渗透系数、颗粒级配、岩土体特性和地下水状态等方面对盾构选型适用性进行了总结和研究。开发了界面友好、人机交互的盾构施工工法软件系统,结合案例工程,对盾构在复杂地质环境特别是穿越富水复合地层的工法选型等施工关键技术进行了深入研究。(2)通过大量开挖面失稳导致的地表塌陷和隧道突涌水灾害的系统收集与整理,分析了灾害的孕险环境和诱发因子,揭示了典型灾害源的赋存特征,提出了开挖面失稳孕灾性评价的指标体系,建立了属性识别模型。依托开发的风险控制软件系统,对高风险段进行动态评价,提出土压平衡盾构施工开挖面失稳的防控措施和应急预案。(3)基于极限分析上限定理,构建了三维旋转体优化破坏模型,利用开挖面临界破坏时外力所做功的功率与土体内部耗散功相等的原理,推导了开挖面极限支护力求解公式,通过MATLAB编程计算程序,求解土压平衡盾构在均质地层和复合地层开挖面失稳临界支护压力。对于复合地层,分别分析了覆土层和穿越层两种工况下隧道埋深、岩土体特性、地下水位等因素对开挖面稳定性的影响,并将计算结果与前人提出的经典破坏模型得出的结果进行了对比分析,验证了理论模型的正确性。(4)基于构建的三维旋转体优化破坏模型,将地下水渗流作用引入到开挖面稳定性上限分析中,推导了开挖面渗流力和坍塌土体中的渗流力求解公式,得到了开挖面渗流力与地下水位的关系,最终求解了渗流作用下复合地层中开挖面支护压力上限解。(5)采用数值计算方法对地下水渗流作用下土压平衡盾构施工力学过程进行了三维数值模拟,分别研究了盾构在均质地层施工和复合地层施工中,不同隧道埋深、岩土体力学特性、地下水状态对开挖面失稳破坏形式、开挖面变形、极限支护力以及地表变形的影响规律。(6)为研究地下水渗流作用下,盾构隧道开挖面失稳过程中开挖面支护压力变化规律和破坏模式,研制了盾构掘进施工模型试验系统、可视化试验平台、防水监测自动化采集系统。以济南地铁R1线盾构隧道穿越灰岩层、砂土层为工程背景,开展了复合地层开挖面稳定性模型试验,研究了复合地层中不同埋深、不同水头高度下,盾构施工开挖面稳定性问题,分析了埋深和水头高度对开挖面极限支护压力、地表沉降、开挖面土体变形规律的影响,揭示了开挖面失稳破坏的演化机制。
[Abstract]:This year, with the rapid development of city construction, the city continues to expand the scale of city density increasing, city traffic gradually deteriorated, environmental pollution is more serious, seriously restrict the further development of economy and society. In order to alleviate the traffic pressure on the ground, to improve the city traffic environment, promote the sustainable development of the city, city construction gradually transformed into a new concept of development of underground space, the shield method is a new construction method, construction of underground space in the city in the gradually increased. But with the development of shield technology and excavation of the increasingly high demand, facing more and more problems, the prediction and control of excavation face stability in construction process very difficult, prone to surface subsidence, excavation face water inrush and other disasters. According to incomplete statistics, China's Beijing, Shanghai, Guangzhou, Nanjing, Shenzhen and other major city in The construction of metro shield tunnel were happened in the major excavation instability accident, resulting in significant economic losses and casualties. According to the environmental conditions of the subway construction is complex, the formation of high sensitivity and control characteristics of stringent standards, face stability prediction and how to effectively control the excavation, become one of the key problems of shield tunnel construction in Metro. Tunnel of EPB shield construction as the main research object, based on the Ji'nan subway shield tunnel project, through indoor experiments, theoretical analysis, numerical calculation, model test and field test methods, in-depth study of complex strata instability mechanism of shield tunnel excavation, excavation face under seepage failure catastrophe evolution characteristics and loss prevention system of stability technology research achievements, has a certain theoretical value and engineering significance mainly includes: (1) put forward the shield construction method selection process, 浠庡湴灞傛笚閫忕郴鏁，

本文编号：1558230