隧道围岩玻璃纤维锚杆锚固性能研究

发布时间：2018-06-04 18:59

本文选题：GFRP锚杆 + 正交实验　；参考：《重庆交通大学》2015年硕士论文

【摘要】：锚固技术经过一个多世纪的发展,已经成为岩土工程领域最重要的支护手段之一。锚杆是锚固体系中最重要的结构体,其物理力学性质对岩土体稳定性和耐久性起着十分重要的作用。普通钢锚杆以其优良的物理力学特性被广泛应用,尤其在基坑工程、隧道工程、边坡工程、地下工程、港口与坝体工程、支挡结构、桥台加固工程等领域。然而,工程实践发现,钢锚杆作为常见结构却存在自重大、运输和安装困难、耐腐蚀性较差等缺陷,这些缺陷影响了其在某些领域的应用。GFRP(Glass Fiber Reinforced Polymer)锚杆是一种新型材料锚杆具有质量轻、强度高、耐电磁、抗腐蚀性好、可加工性好、抗疲劳性能好等特点。GFRP锚杆替代普通钢锚杆用于支护工程,可在克服钢锚杆某些方面的不足,必将推动锚固技术的新发展以及新应用。目前,国内外已有不少GFRP锚杆成功应用的实例,但是对玻璃纤维锚杆的理论研究相对较少,为加快玻璃纤维锚杆技术推广,应加强其在隧道工程、边坡工程及地下工程等领域的研究,玻璃纤维锚杆的理论研究概括起来主要两个方面:一是宏观方面,主要体现在锚固体系加固后,岩土体承载力、岩土体物理力学参数等锚固效果方面的研究;另一方面微观角度,从锚固体系荷载传递途径出发,研究荷载作用下沿锚固长度的应力、应变分布及传递规律,重点研究锚杆杆体与注浆体、注浆体与岩土体界面上物理力学特性,以上两个界面往往是控制锚固体系正常工作的关键因素。首先通过对锚固机理论研究,研究玻璃纤维锚杆现阶段的锚固机理,分析玻璃纤维锚杆粘结应力的分布规律、分布函数。通过对玻璃纤维锚杆物理力学性能的研究,确定玻璃纤维锚杆的破坏形态。通过对玻璃纤维锚杆进行现场正交实验,研究锚固体系中的锚固直径、锚杆直径、锚固长度、砂浆强度等因素对锚固力的影响,并通过极差分析、方差分析确定影响锚固体系力学指标的关键因素,通过回归分析建立玻璃纤维锚杆承载力、平均粘结应力与关键因素之间的函数关系,为类似工程锚杆重要物理参数提供借鉴。结合现有的理论成果和工程实践,研究锚杆锚固机理、锚固体系的破坏形态。利用成熟软件Flac3D模拟实际双侧壁导坑法施工,通过对围岩体应力、应变、位移等指标的检验,评价玻璃纤维锚杆作为系统锚杆、临时锚杆的可行性。
[Abstract]:Anchorage technology has become one of the most important supporting methods in geotechnical engineering field after more than a century's development. Anchor rod is the most important structure in anchoring system, and its physical and mechanical properties play an important role in the stability and durability of rock and soil. Common steel anchors are widely used for their excellent physical and mechanical properties, especially in the fields of foundation pit engineering, tunnel engineering, slope engineering, underground engineering, port and dam body engineering, retaining structure, bridge abutment reinforcement and so on. However, it has been found in engineering practice that the steel anchor rod, as a common structure, has some defects, such as heavy weight, difficult transportation and installation, poor corrosion resistance, etc. These defects affect its application in some fields. GFRP Glass Fiber Reinforced Polymer) bolt is a new type of material bolt with light weight, high strength, electromagnetic resistance, good corrosion resistance and good processability. GFRP anchors can be used in support engineering instead of common steel anchors, which can overcome the shortcomings of some aspects of steel anchors and will promote the new development and application of anchoring technology. At present, there are many examples of successful application of GFRP bolt at home and abroad, but the theoretical research on glass fiber bolt is relatively few. In order to speed up the popularization of glass fiber bolt technology, it should be strengthened in tunnel engineering. In the field of slope engineering and underground engineering, the theoretical research of glass fiber bolt is summarized in two aspects: one is macro aspect, which is mainly reflected in the bearing capacity of rock and soil after the reinforcement of anchor system. On the other hand, from the microscopic point of view, the stress, strain distribution and transfer law along the Anchorage length are studied from the point of view of the load transfer way of the Anchorage system. Emphasis is placed on the physical and mechanical properties of the bolt body and grouting body and the interface between the grouting body and the rock and soil. The above two interfaces are often the key factors to control the normal operation of the anchoring system. Firstly, the anchoring mechanism of glass fiber bolt is studied by studying the theory of anchoring machine, and the distribution law and distribution function of bond stress of glass fiber bolt are analyzed. Through the study of the physical and mechanical properties of the glass fiber bolt, the failure form of the glass fiber bolt is determined. Based on the field orthogonal experiment of glass fiber bolt, the influence of anchoring diameter, anchor rod diameter, anchor length and mortar strength on the anchoring force is studied. The key factors affecting the mechanical index of anchoring system are determined by variance analysis. The functional relationship between the bearing capacity of glass fiber anchor rod, the average bond stress and the key factors is established by regression analysis, which provides a reference for the important physical parameters of anchor rod in similar projects. Combined with the existing theoretical results and engineering practice, the anchoring mechanism of anchor rod and the failure mode of anchor system are studied. By using the mature software Flac3D to simulate the construction of the actual double-side wall guide pit method, the feasibility of the glass fiber bolt as the system anchor and the temporary anchor is evaluated by checking the stress, strain and displacement of the surrounding rock mass.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.7

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