圆形巷道围岩变形分区的理论与试验研究

发布时间：2018-03-24 21:38

本文选题：巷道变形分区　切入点：应变软化模型　出处：《安徽理工大学》2017年博士论文

【摘要】：长期以来,软岩巷道(隧道)围岩变形分区的研究在国内外始终是一个较热的论题。自上世纪30年代至今的90余年里,围绕这一论题数百位专家学者进行了多方位、多角度的钻研,公开发表了数百篇学术论文,产生了很多研究成果。其中代表性的成果主要有芬涅尔计算公式、松动圈理论、三阶段应变软化模型、四阶段应变软化模型等,这些成果对巷道(隧道)支护理论与技术的发展均产生了重要影响。不可否认,该论题的研究目前仍然处于一个发展阶段,其中某些问题依然明显地存在着需要商榷的地方,具体可以概括为5个方面:(1)作为分区研究基础的"三阶段应变软化模型"和"四阶段应变软化模型"均没有考虑到岩石的蠕变特性,而是以快速加载情况下获得的岩石的峰值抗压强度作为模型的峰值应力,忽视了围岩的实际受力状态与快速加载情况之间的差异性,忽略了岩石在长期持续载荷作用下存在稳定蠕变上下阈值这一重要客观事实。(2)在进行分区边界位置的确定时,对塑性软化区域的岩石内摩擦角和粘聚力的变化情况认识不清,形成了多种不客观的研究假设;(3)没能很好地理解"塑性流动区应力计算公式与地应力无关"这一重要研究成果的深层含义,错误地将该区域内应力分布规律与地应力无关理解为"塑性流动区内应力与地应力无关"。(4)忽视了围岩稳定蠕变终止轨迹线的存在。(5)确定变形分区边界位置的解析公式中依然存在着需要主观规定的元素。针对上述存在的问题,文章以基于蠕变特性的围岩变形分区边界位置的确定和应力分布规律的获得为目标,对围岩塑性软化阶段内摩擦角和粘聚力变化规律、基于蠕变特性的围岩应变软化模型和各分区应力和位移分布规律进行了较为深入的理论与实验研究,最后又以淮南矿区千米深井(潘一东煤矿)-848m充电整流硐室为研究对象较为详细地介绍了本文理论的实践应用。获得了 7个重要研究成果:(1)论证了围岩塑性软化阶段内摩擦角变化很小、粘聚力下降很大的观点,对"粘聚力与内摩擦角的变化趋势与岩石强度的变化趋势应保持一致"的观点给予了纠正。(2)基于围岩应变软化模型中应力-应变之间的线性关系,推论获得塑性软化阶段环向应力与径向应力之间存在线性关系这一重要性质,同时论证了该阶段粘聚力软化模量为一常量的性质。(3)揭示了围岩中稳定蠕变上下阈值的存在,创建了符合围岩实际受力情况及岩石力学性质的"围岩4阶段应变软化新模型"。(4)给出了各种类型变形分区产生的条件,推导出了各分区应力分布规律的解析式和位移分布规律的解析式。(5)结合不同围压下峰值抗压强度拟合直线、稳定蠕变上下阈值拟合直线和残余强度拟合直线,建立了围岩分区类型分析与边界应力确定示意图。利用这一示意图可以十分简单地通过图解法和解析法获得围岩变形分区的类型和分区界面应力的数值。(6)系统而全面地给出了各分区边界应力和边界位置的求解公式及相应的推导过程,为巷道(隧道)支护参数的量化设计提供了很好的理论依据。针对各种分区类型和支护强度,明确了巷道内边缘环向应力在围岩4阶段应变软化模型中的对应位置,使得围岩变形机理的研究步入了真正意义上的量化研究范畴。(7)给出了套筒致裂单孔三维地应力测试的原理与方法。通过具体实例,详细地给出了围岩分区类型、分区边界应力和边界位置的确定方法,通过求解结果与现场实测结果及数值模拟结果的对比,论证了本文理论和方法的科学性和可靠性。文章的研究方法体现了两个基本特征。首先是理论、试验和实践相结合的特征。整篇文章以理论分析为主线,试验研究贯穿其中,现场应用辅以说明。第二个特征是理论分析以变形稳定后的围岩为对象,不考虑围岩复杂、多变的流变过程。整个研究中涉及蠕变的参数仅有"稳定蠕变上、下阈值"两个,不仅使得研究思路更加清晰,同时也最大程度地简化了研究过程。本文的研究成果对煤矿软岩巷道(隧道)变形机理的量化研究和支护参数的量化设计具有重要的价值。
[Abstract]:For a long time, soft rock tunnel (tunnel) study on surrounding rock deformation partition at home and abroad is always a hot topic. Since the last century since 30s, more than 90 years, around the topic of hundreds of experts and scholars conducted a multi-faceted, multi angle study, published hundreds of papers, the a lot of research results. The principal results of the calculation formula of Fennieer, loose circle theory, three stage strain softening model, four stage strain softening model, the results of the tunnel (tunnel) support theory and technology development have made important influence. It is undeniable that this research is still in the a stage of development, some problems still has the obvious need to discuss the specific place, can be summarized as 5 aspects: (1) as the basis for division of "three stage strain softening model" and "four stages of strain softening The model does not take into account the creep characteristics of rock, but in the case of rapid loading of rock peak strength as a model of the peak stress, the difference between the actual neglect of surrounding rock stress state and fast loading, ignoring the existence of stable rock creep under the threshold of this important fact in the long term continuous loading. (2) in determining the partition boundary, the plastic softening zone of rock changes of internal friction angle and cohesion is unclear, the formation of a variety of hypotheses not objective; (3) did not have a good understanding of plastic flow stress calculation formula with the deep meaning of "stress independent of this important research results, the error area stress distribution and the stress not understood as" plastic flow stress and stress free. "(4) ignored the rock steady creep termination Traces of existence. (5) to determine the analytical formulae of the deformation partition boundary positions still need subjective definition elements. In view of the above problems, this paper based on the characteristics of rock creep deformation to obtain partition boundary positions and stress distribution as the goal, to the surrounding rock plastic softening stage internal friction angle the cohesion and the variation of the creep properties of rock strain softening model and regional distribution of stress and displacement are investigated theoretically and experimentally based on in-depth, and finally to Huainan mining area of 1000m deep (Pan Yidong coal mine) -848m charging rectifier chamber as the research object is introduced in detail. The practical application of the theory. 7 important findings: (1) demonstrated the rock plastic softening stage variation of internal friction angle is small, the cohesion decreased greatly, changes of cohesion and internal friction angel The change trend of rock strength and should be consistent point of view gives correct. (2) the relationships between stress and strain between the model of rock strain softening based on inferences obtained plastic softening stage of circumferential stress and radial stress are the important properties of the linear relationship between, and demonstrates the stage stick for a constant cohesion softening modulus properties. (3) revealed the presence of stable creep threshold of surrounding rock, created in line with the actual rock stress and rock mechanics of surrounding rock "4 stage". The new strain softening model (4) of various types of deformation partitions to create conditions are given, derived the analytical formula of partition stress distribution equation and displacement distribution. (5) with the peak strength of linear fitting different confining pressure, stable creep under threshold linear fitting and residual strength of fitting a straight line, built the zonal Schematic diagram of stress type and boundary. Using this schematic can be very simple to obtain numerical zonal type and partition interface deformation stress by graphic method and analytic method. (6) systematically gives each partition boundary should be solving formula of force and the location of the boundary and derivation of the corresponding tunnel (tunnel), which provides a good theoretical basis for quantitative design of supporting parameters. According to the partition type and supporting intensity, the roadway edge hoop stress in the surrounding rock strain softening stage 4 corresponding position in the model, makes the research on the deformation mechanism of surrounding rock into the category of quantitative research on real significance the. (7) gives the sleeve fracturing principle and test method of 3D geostress of single hole. Through concrete examples, detailed rock partition type is given, a method for determining stress partition boundary and the boundary position, by seeking Comparison of solution results with experimental results and numerical simulation results, proving the correctness and reliability of the theory and method in this paper. The research method of this article reflects the two basic characteristics. First is the theory and practice of combining the characteristics of the test. With the theoretical analysis as the main line, which runs through the experimental research, supplemented by field application the second feature is described. Theoretical analysis on the deformation of surrounding rock stability after the object, without considering the complex surrounding rock, the rheological process variable. The creep parameters of the whole study involved only "steady creep, under the threshold of two, not only makes the research ideas more clearly, but also greatly simplifies the research process. The results of this soft rock roadway in coal mine (tunnel) has an important value in the quantitative research on the deformation mechanism and supporting parameters of quantitative design.

【学位授予单位】：安徽理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD322

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