基于新意法的软弱围岩隧道预加固作用分析

发布时间：2019-05-27 03:30

【摘要】：新意法的核心理念是利用加固后的超前核心土为隧道稳定的工具。基于新意法预加固原理的全断面开挖具有施工速度快、经济效益高等优点,并已在很多地质条件相对较差的隧道工程中得以成功运用。但其理论研究多数重在分析掌子面的挤出变形、预收敛变形及收敛变形,往往忽略了预加固措施对掌子面前方土体的影响。同时,结合我国现阶段隧道施工水平、机械化水平及复杂的地质条件,预加固后的全断面开挖往往不能带来应有的效率及安全。而现阶段的一些开挖方式及超前加固方式,在一定程度上与新意法原理相契合。本文针对预加固对掌子面前方土体空间塑性屈服区域的影响及软弱围岩条件下全断面开挖适用性做了一些研究,具体完成的工作如下:(1)全面系统地介绍了新意法的基本理论,并总结了预加固措施在国内外的研究及应用现状;(2)对掌子面的稳定性原理作出了总结,并分析了影响掌子面稳定性的因素。通过水平条分掌子面前方土体进行了算例分析,得到了掌子面稳定性与核心土加固作用的关系;(3)通过对不同工况的数值模拟分析,系统地阐述了预加固措施对掌子面前方空间塑性屈服区域发展的影响,以及不同的核心土预加固长度在不同围岩条件下对空间塑性屈服区域、掌子面挤出位移等的影响。(4)在不同围岩条件下对结合管棚支护的短台阶开挖及掌子面玻璃纤维锚杆预加固的全断面开挖进行了对比分析,并建议了在V级、VI级围岩条件下的开挖方式。最后,对现有的问题和进一步的研究进行了简要的论述。
[Abstract]:The core idea of the new method is to use the reinforced advanced core soil as a tool for tunnel stability. The full section excavation based on the pre-reinforcement principle of the new method has the advantages of fast construction speed and high economic benefit, and has been successfully applied in many tunnel projects with relatively poor geological conditions. However, most of the theoretical research focuses on the analysis of extrusion deformation, pre-convergence deformation and convergent deformation of the palm surface, and often ignores the influence of the pre-reinforcement measures on the soil in front of the palm surface. At the same time, combined with the current tunnel construction level, mechanization level and complex geological conditions, the full section excavation after pre-reinforcement often can not bring the due efficiency and safety. At present, some excavation methods and advanced reinforcement methods are consistent with the principle of new method to a certain extent. In this paper, the influence of pre-reinforcement on the spatial plastic yield area of soil in front of palm surface and the applicability of full section excavation under the condition of weak surrounding rock are studied. The specific work is as follows: (1) the basic theory of the new method is introduced comprehensively and systematically, and the research and application status of the pre-reinforcement measures at home and abroad are summarized. (2) the stability principle of palm surface is summarized, and the factors affecting the stability of palm surface are analyzed. Through the analysis of the soil in front of the horizontal strip in front of the palm surface, the relationship between the stability of the palm surface and the reinforcement of the core soil is obtained. (3) through the numerical simulation analysis of different working conditions, the influence of pre-reinforcement measures on the development of plastic yield area in front of palm surface is systematically expounded. And different prereinforcement lengths of core soil under different surrounding rock conditions to the spatial plastic yield area, (4) under different surrounding rock conditions, the short step excavation of combined pipe shed support and the full section excavation of glass fiber bolt pre-strengthened on palm surface are compared and analyzed, and it is suggested that the excavation of short step combined with pipe shed support and full section excavation of glass fiber bolt pre-strengthened on palm surface should be in V grade. Excavation mode under the condition of VI class surrounding rock. Finally, the existing problems and further research are briefly discussed.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4

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