基于收敛—约束原理的地下洞室稳定性分析

发布时间：2018-03-19 14:41

本文选题：地下工程　切入点：收敛-约束原理　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：地下工程作为现代工程中的重要领域之一,其主要特征表现为在已赋存的应力场中通过开挖、支护等工序形成结构。地下结构不仅承受周边地层的变形荷载,同时其变形也受到地层的限制约束。而目前地下结构设计中,通常采用以经验围岩分级为主,以数值模拟得到其应力和应变分布为辅的设计方法。与地面结构设计方法中稳定表征指标的成熟性相比,本文针对现代地下结构设计方法中缺乏物理意义明确的表征指标不足之处,结合收敛-约束原理来开展研究。基于收敛-约束原理的地下结构稳定性分析方法,该方法主要涉及到地层、支护两方面。地层方面由于赋存环境及岩体力学变形机理复杂而难于确切判断,因此利用围岩特性曲线描述开挖后周边地层的力学机理和变形特性;而支护结构构建方面则(多数以锚杆、喷射混凝土以及钢架等支护材料进行构建)相对比较固定。本文根据收敛-约束的基本原理及重要因素,具体研究内容如下:首先,根据国内外已有的研究成果,较为全面地阐述了收敛-约束原理的基本原理、主要构成因素、研究现状及其发展历史。以经典的圆形洞室进行弹塑性分析,选取力学开挖效应满足Mohr-Coulomb准则的Kastner公式及Duncan公式构建围岩特性曲线方程。其次,分析支护结构中支护单元对围岩的作用机制以及各自相应的力学特性,构建了联合支护中锚喷支护的支护特征曲线,确定了锚喷支护的联合刚度方程、最大支护压力方程及支护特征方程。再有,在构建围岩收敛曲线和支护特征曲线的前提下,综合考虑除两者之外的其他收敛-约束原理的构成因素,依据荷载和图示原理导出地下结构的稳定系数。通过工程实例对新方法的实现过程进行了展示。分析了围岩力学参数变化对两者稳定系数的影响,对比了各自稳定系数的差异性。最后,开展室内模型试验工作。进行了模型相似材料配比设计、强度分析、不同地层类型的模拟、地层开挖后应力-应变分布情况的量测等工作,结合理论对实测所得数据进行了分析验证。
[Abstract]:As one of the most important fields in modern engineering, underground engineering is characterized by the formation of structures by excavation and support in existing stress fields. At the same time, the deformation is also restricted by the strata. At present, in the design of underground structures, the classification of the surrounding rock is usually used as the main method. The numerical simulation results show that the distribution of stress and strain is complementary to the design method, and compared with the maturity of the stability index in the design method of ground structure, In this paper, aiming at the lack of clear physical representation index in modern underground structure design method, combined with convergence constraint principle, the stability analysis method of underground structure based on convergence constraint principle is studied. The method mainly involves two aspects: stratum and support. It is difficult to judge exactly because of the complex existing environment and mechanical deformation mechanism of rock mass, so the surrounding rock characteristic curve is used to describe the mechanical mechanism and deformation characteristics of surrounding strata after excavation. However, the construction of supporting structure (most of which are constructed by bolting, shotcrete and steel frame) is relatively fixed. According to the basic principle and important factors of convergence-constraint, the specific research contents are as follows: first, According to the existing research results at home and abroad, the basic principle of convergence-constraint principle, the main composing factors, the present research situation and its development history are expounded in detail. The elastoplastic analysis of classical circular cavern is carried out. The Kastner formula and Duncan formula of mechanical excavation effect satisfying Mohr-Coulomb criterion are selected to construct the characteristic curve equation of surrounding rock. Secondly, the mechanism of supporting unit acting on surrounding rock and their respective mechanical properties are analyzed. The supporting characteristic curve of bolting and shotcreting in combined support is constructed, and the joint stiffness equation, maximum support pressure equation and supporting characteristic equation of bolting and shotcreting support are determined. Furthermore, under the premise of constructing convergence curve and supporting characteristic curve of surrounding rock, Taking into account the composition of the principle of convergence and constraint in addition to the two, According to the principle of load and diagram, the stability coefficient of underground structure is derived. The realization process of the new method is demonstrated by an engineering example, and the influence of the change of mechanical parameters of surrounding rock on the stability coefficient of both is analyzed. The differences of their stability coefficients are compared. Finally, the laboratory model tests are carried out. The design of similar material ratio, the strength analysis, the simulation of different strata types are carried out. The measurement of the stress-strain distribution after the excavation of the stratum is analyzed and verified by combining the theory with the measured data.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU457

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