喷射纤维混凝土基本力学性能及其在地下工程中应用研究

发布时间：2018-03-22 00:40

本文选题：地下洞群　切入点：交叉结构　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着公路行业的不断发展,长大公路隧道在近年不断涌现。与此同时,地下风机房洞群交叉结构稳定性分析已成为长大隧道辅助通道建设的关键技术之一。因此,开展隧道地下风机房洞室群交叉结构稳定性分析具有重要的理论意义和工程实践价值。本文以宝塔山2#风机房地下洞群不同类型交叉结构为研究对象,采用理论分析、室内试验以及数值分析相结合方法,以聚丙烯纤维混凝土在隧道交叉结构中的运用为主线,对聚丙烯纤维混凝土基本力学性能和风机房交叉结构采用该支护材料后在开挖过程中的变形、裂缝、接触应力等变化规律展开了系统性的分析,为地下交叉结构的安全施工提供了技术保障。主要研究内容如下：(1)通过理论分析和室内模拟实验,研究素混凝土强度在掺不同含量聚丙烯纤维后的变化规律并得出对应的强度指标。(2)针对风机房地下洞群交叉结构的复杂性,运用工程类比法提出不同交叉类型结构的支护参数,建立三维数值模型,通过分析地下洞群不同交叉段在采用聚丙烯纤维混凝土之后的围岩变形、结构内力状态,支护结构裂缝分布及破坏形式等施工力学行为,来评价围岩及支护结构的稳定性,为以后类似工程的建设提供一定的理论及技术保障。(3)基于接触算法,针对不同类别的典型交叉结构单元分别建立接触单元,研究分析了围岩与支护结构之间的法向、切向接触应力,探明了不同交叉形式下,法向、切向接触应力沿隧道纵横向的整体分布形态、集中程度以及变化规律,同时对比分析了法向、切向随开挖面积的变化规律。(4)通过分析隧道不同交叉段的纵向变形规律,探明了不同交叉结构的变形影响范围：双T型交叉的影响范围是交叉段最大跨径的1.9倍,十字交叉的影响范围是交叉段最大跨径的2.1倍,T型交叉的影响范围是交叉段最大跨径的1.4倍。
[Abstract]:With the continuous development of highway industry, long and long highway tunnels have been emerging in recent years. At the same time, the stability analysis of cross-structure of underground fan caverns has become one of the key technologies in the construction of auxiliary tunnels. It is of great theoretical significance and practical value to carry out the stability analysis of cross structure of tunnel underground fan chamber group. This paper takes different types of cross structure of underground tunnel group in Baota Mountain as the research object, and adopts theoretical analysis. With the combination of laboratory test and numerical analysis, the application of polypropylene fiber reinforced concrete in tunnel cross structure is the main line. The deformation, crack and contact stress of polypropylene fiber reinforced concrete (PP fiber concrete) during excavation are analyzed systematically by using the supporting material in the cross-structure of the wind engine room and the basic mechanical properties of polypropylene fiber concrete, and the variation of the deformation, crack and contact stress during the excavation process is analyzed systematically. It provides a technical guarantee for the safe construction of underground cross structures. The main research contents are as follows: 1) through theoretical analysis and indoor simulation experiments, In view of the complexity of cross structure of underground cavity group in fan building, the support parameters of different cross type structures are put forward by using engineering analogy method, and the change law of strength of plain concrete with different content of polypropylene fiber is studied and the corresponding strength index is obtained. A three-dimensional numerical model is established to analyze the deformation of surrounding rock, the state of internal force of structure, the distribution of cracks and the failure form of supporting structure in different cross sections of underground cavity group after adopting polypropylene fiber concrete. To evaluate the stability of surrounding rock and supporting structure, to provide certain theoretical and technical support for the construction of similar projects in the future. Based on the contact algorithm, contact units are established for different types of typical cross structural units. The normal and tangential contact stress between surrounding rock and supporting structure is studied and analyzed. The distribution pattern, concentration degree and variation law of normal and tangential contact stress along the longitudinal and horizontal direction of tunnel under different cross forms are found out. At the same time, the variation law of normal and tangential direction with excavation area is analyzed. The influence range of deformation of different cross structures has been proved: the influence range of double T-type cross is 1.9 times of the maximum span of cross section. The influence range of cross is 2.1 times of the maximum span of the cross section and 1.4 times of the maximum span of the cross section.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U454

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