深埋条件下隧道稳定性评价方法及应用研究

发布时间：2018-06-28 14:46

本文选题：围岩质量 + 跨度　；参考：《北京科技大学》2015年博士论文

【摘要】：山岭隧道建设过程中,围岩及支护结构失稳是最为常见的工程灾害。隧道一旦失稳,将造成巨大的损失。如何用更加科学的方法对隧道稳定性进行评价,为隧道开挖及支护设计提供充分的理论依据,保障隧道工程安全顺利施工,是隧道建设者亟待解决的重大技术难题。本文以“高速公路隧道开挖诱发工程灾害辨识及预警系统研究”项目为依托,以山平高速鸳鸯会隧道深埋段为研究对象,综合利用理论分析、数值模拟、监控量测等技术手段,对复杂条件下深埋岩质隧道稳定性评价方法及应用开展研究,并取得以下主要研究成果： (1)众所周知,岩体具有显著的尺寸效应,但国内外常用的岩体质量评价及分类方法均未考虑工程岩体的尺寸效应,本论文为考虑这一重要因素,在围岩基本质量评价法的基础上,引入跨度影响修正系数,量化了跨度对隧道围岩质量的影响,实现了考虑围岩尺寸效应的岩体质量评价；基于粗糙集和未确知测度理论,建立了新的隧道围岩质量评价模型。利用两种方法平行分级,相互验证,可为研究复杂地质条件下隧道稳定性问题提供理论基础。 (2)基于广义Hoek-Brown屈服准则,建立了通用隧道纵向变形曲线计算模型。考虑隧道围岩质量及应力水平对开挖面空间效应的影响,建立了能够量化不同围岩质量及应力水平下开挖面空间效应差异的纵向变形曲线函数表达式,为正确应用收敛-约束法进行隧道开挖支护设计提供理论依据。 (3)结合围岩质量评价指标BQ值,以规范所给极限相对位移值域为基础,参考大量隧道位移实测值及前人研究成果,建立了考虑多因素影响的初支极限相对位移模型,实现了初支极限相对位移连续化,为隧道初支结构安全评价提供了量化基础。 (4)基于上述研究成果,提出并验证了基于收敛-约束法的隧道开挖进尺优化方法。基于收敛-约束原理,以选定合理的开挖进尺为目标,以控制围岩支护结构安全系数为手段,结合前文确定的隧道纵向变形曲线,反推支护起始作用位置,确定合理的开挖进尺。以鸳鸯会隧道左洞LK179+580-LK179+920区段为例,得出该区段中V类围岩的合理开挖进尺为1.5m。
[Abstract]:In the process of mountain tunnel construction, the instability of surrounding rock and supporting structure is the most common engineering disaster. Once the tunnel is unstable, it will cause huge losses. How to evaluate the stability of tunnel by more scientific method, provide sufficient theoretical basis for tunnel excavation and support design, and ensure the safe and smooth construction of tunnel engineering, is a major technical problem to be solved urgently by tunnel builders. Based on the project of "disaster Identification and early warning system Research of Expressway Tunnel excavation induced Engineering", this paper takes the deep buried section of Shanping High-speed Yuanyang Yazhui Tunnel as the research object, and synthetically utilizes the technical means such as theoretical analysis, numerical simulation, monitoring and measurement, etc. The evaluation method and application of the stability of deep buried rock tunnel under complex conditions are studied. The main research results are as follows: (1) it is well known that rock mass has remarkable size effect. However, the size effect of engineering rock mass is not taken into account in the evaluation and classification of rock mass quality at home and abroad. In this paper, in order to consider this important factor, the span influence correction coefficient is introduced on the basis of the basic quality evaluation method of surrounding rock mass. The influence of span on the quality of surrounding rock mass of tunnel is quantified, and the evaluation of rock mass quality considering the size effect of surrounding rock mass is realized, and a new evaluation model of surrounding rock mass quality of tunnel is established based on rough set and unascertained measure theory. The parallel classification and mutual verification of the two methods can provide a theoretical basis for the study of tunnel stability under complex geological conditions. (2) based on the generalized Hoek-Brown yield criterion, a general tunnel longitudinal deformation curve calculation model is established. Considering the influence of surrounding rock mass and stress level on the spatial effect of excavation surface, the function expression of longitudinal deformation curve can be established to quantify the spatial effect difference of excavation face under different surrounding rock mass and stress level. It provides a theoretical basis for correctly applying the convergent constraint method to the design of tunnel excavation support. (3) combining with the value of the surrounding rock quality evaluation index, the value of the limit relative displacement value given by the code is taken as the foundation. Referring to a large number of tunnel displacement measurements and previous research results, the initial limit relative displacement model considering the influence of multiple factors is established, and the initial limit relative displacement continuity is realized. It provides a quantitative basis for the safety evaluation of tunnel initial branch structure. (4) based on the above research results, the paper proposes and verifies the optimization method of tunnel excavation scale based on convergent constraint method. Based on the principle of convergence and constraint, with the aim of selecting a reasonable excavation scale and controlling the safety factor of surrounding rock support structure, combining with the tunnel longitudinal deformation curve determined in the previous paper, the starting position of supporting is pushed back. Determine a reasonable excavation advance. Taking the LK179 580-LK179 920 section of the left tunnel of Yuanyanhui Tunnel as an example, the reasonable excavation scale of V type surrounding rock in this section is 1.5 m.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U451

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