软弱地层隧道超前预加固措施作用效果研究

发布时间：2018-11-04 11:48

【摘要】：本文以合福客运专线白桦隧道为工程背景,利用数值模拟的研究手段,对软弱地层大断面隧道超前预加固措施的加固效果进行了全面系统的研究。为大断面隧道的全断面施工安全控制提供理论指导。本文主要完成了以下研究工作： 1.针对软弱围岩的特点,阐述了超前预加固措施的适用条件和目标,为下文系统地研究不同超前预加固措施力学效应及加固效果奠定基础。 2.对不同超前预加固措施的加固机理进行深入研究,进而提出适合不同加固措施的数值模拟方法,为下文加固效果分析提供理论基础。 3.结合工程实际情况,选取常见超前预加固措施进行加固效果分析,分别研究不同加固措施支护参数变化对加固效果的影响,选取隧道开挖后掌子面临空阶段最大拱顶沉降、掌子面最大水平位移、支护参数变化引起的隧道变形等指标对加固效果进行评价。 4.根据新意法的理念,研究三种不同新型超前支护组合方式,分别为超前小导管+掌子面锚杆、超前管棚+掌子面锚杆、水平旋喷桩+掌子面锚杆。研究关键支护参数变化对组合加固措施加固效果的影响,并与单独加固的加固效果进行对比,探讨组合加固措施的优势。 5.针对实际工况,通过对实测数据和数值模拟结果的分析,探讨在采用组合加固措施的情况下,白桦隧道采用全断面法施工的可能性。本文研究成果对软弱围岩等不良地质条件下隧道安全快速施工的理论研究和工程实践具有一定指导意义。研究表明,在已有超前预加固措施的基础之上,为实现隧道安全快速施工,可以通过对掌子面前方核心土预加固以及核心土外预支护相结合的方式,大幅提高核心土的强度,同时改善其受力情况,显著减少掌子面的变形和隧道拱顶沉降,提高施工过程中掌子面的稳定性。
[Abstract]:Taking Bai Hua Tunnel of Hefu passenger dedicated Line as the engineering background and by means of numerical simulation, this paper makes a comprehensive and systematic study on the reinforcement effect of advance pre-reinforcement measures for large-section tunnels in weak strata. It provides theoretical guidance for the safety control of the whole section construction of the large section tunnel. The main work of this paper is as follows: 1. In view of the characteristics of weak surrounding rock, the suitable conditions and objectives of advance pre-reinforcement measures are expounded, which lays a foundation for the systematic study of mechanical effects and reinforcement effects of different pre-reinforcement measures below. 2. In this paper, the reinforcement mechanism of different pre-reinforcement measures is deeply studied, and the numerical simulation method suitable for different reinforcement measures is put forward, which provides a theoretical basis for the analysis of reinforcement effect below. 3. Combined with the actual situation of the project, the common pre-reinforcement measures are selected to analyze the reinforcement effect, and the influence of the different reinforcement measures on the reinforcement effect is studied, and the maximum arch settlement is selected after the tunnel excavation. The maximum horizontal displacement of the face and the tunnel deformation caused by the change of supporting parameters are evaluated. 4. According to the idea of Xinyi method, three kinds of new advanced support combination methods are studied. They are the small lead pipe face anchor, the leading pipe shed palm anchor, and the horizontal rotary shotcrete pile palm bolt. The influence of key support parameters on the reinforcement effect of combined reinforcement measures is studied, and the advantages of combined reinforcement measures are discussed compared with those of individual reinforcement measures. 5. Based on the analysis of measured data and numerical simulation results, the possibility of using full section method to construct Bai Hua tunnel under combined reinforcement measures is discussed in the light of actual working conditions. The research results of this paper have certain guiding significance for the theoretical research and engineering practice of tunnel safety and rapid construction under the bad geological conditions such as soft surrounding rock. The research shows that, on the basis of the existing pre-reinforcement measures, in order to realize the safe and rapid construction of the tunnel, the strength of the core soil can be greatly improved by combining the core soil pre-reinforcement in front of the face with the core soil pre-support outside the core soil. At the same time, the deformation of the face and the settlement of the tunnel arch are greatly reduced, and the stability of the face is improved.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4

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