GFRP抗浮锚杆外锚固试验研究及有限元模拟

发布时间：2018-05-19 22:42

本文选题：GFRP + 抗浮锚杆　；参考：《青岛理工大学》2013年硕士论文

【摘要】：地铁、地下商场和地下停车场等地下结构由于地下水存在而面临抗浮问题。一般建筑工程多采用抗浮锚杆作为抗浮措施，而地铁工程抗浮措施通常采用抗拔桩。青岛地区广泛分布的中风化和微风化花岗岩地质条件给抗拔桩施工带来了很大困难，，甚至难以达到设计桩长。传统金属锚杆成孔效率高，但由于锚固体直径小，锚杆筋体保护层厚度有限，易受地铁运行中所产生的杂散电流电化学腐蚀而难以满足永久性抗浮要求。玻璃纤维增强聚合物GFRP（Glass Fiber ReinforcedPolymer）锚杆具有抗拉强度高、结构轻、耐腐蚀和不受杂散电流影响等特点，将GFRP锚杆应用于地铁抗浮工程中将有独特优势。目前GFRP筋用于抗浮锚杆的研究较少。GFRP抗浮锚杆与钢筋抗浮锚杆在内锚固端锚固机理、应力分布规律方面没有系统的对比分析；GFRP抗浮锚杆外锚固端变形特性和新型纤维增强塑料锚具等方面的理论尚不完善。为研究GFRP锚杆用于地铁抗浮工程的可行性，推广GFRP材料的应用范围。在课题组前期进行的钢筋抗浮锚杆和GFRP抗浮锚杆试验研究的基础上，本文对两种锚杆的承载特性做了对比分析研究，得出了两种锚杆在第一界面应力分布规律方面的异同、内锚固端锚固承载力及各自的破坏机理。在GFRP抗浮锚杆外锚固方面，本文设计对拉试验对GFRP锚杆外锚固端荷载-滑移特性和一种新型托盘螺母锚具进行试验研究。在试验研究的基础上，本文利用有限元程序ANSYS对试验中两种不同锚固长度的试件建立模型进行了荷载-滑移关系的计算分析。本文的主要研究成果如下：（1）本文详细分析了钢筋锚杆和GFRP锚杆的承载机理与承载力的决定因素。以两种材料各自的特性为出发点，对两种锚杆出现的不同破坏形式和破坏机理进行了分析。归纳整理了国内外关于两种材料筋体在混凝土中锚固长度的计算公式和粘结滑移本构模型。（2）GFRP锚杆可通过植入光纤光栅传感器进行锚杆内力的测试，通过植入筋体的方式可得到较高的成活率和测试精度。试验结果详细分析了两种锚杆工作状态下轴力和剪应力分布规律方面的异同点，并对应力分布曲线的不同之处进行了分析。（3）在GFRP锚杆外锚固试验中，对拉试件的试验方式避免了传统锚杆试验中夹具对GFRP筋体的破坏，省去了对筋体的复杂处理和保护措施，有效的进行了拉拔试验。试验过程简单流畅，试验效率大大提高。对GFRP在混凝土中的临界锚固长度进行了试验分析，两种不同锚固长度的纯筋锚固试件发生了两种不同的破坏形式，确定了临界锚固长度的取值范围。对新型玻璃纤维材料锚具的锚固效果和锚固效率进行了分析，并提出了锚具进一步改进的建议。（4）本文通过试验分析得出了GFRP筋在混凝土中的荷载-滑移曲线，并用ANSYS进行了外锚固端的模拟分析。文章认为在相应的极限荷载作用下，内锚固端和外锚固端变形均较小，锚杆的内外锚固端变形之和在工程允许范围内。
[Abstract]:The underground structures , such as subway , underground mall and underground parking lot , are faced with anti - floating problems due to the existence of underground water . Generally , anti - floating anchor rods are used as anti - floating measures in general construction projects , and the anti - floating measures of subway engineering are often adopted as anti - uplift measures . The traditional metal anchor rod has high hole efficiency , but it is difficult to meet the permanent anti - floating requirement due to the small diameter of anchor solid and limited thickness of the protective layer of the anchor bar . The glass fiber reinforced polymer ( Glass Fiber Reinforced Polymer ) anchor rod has the characteristics of high tensile strength , light structure , corrosion resistance and no influence on stray current , and the like , and the glass fiber reinforced polymer ( glass fiber reinforced polymer ) anchor rod has unique advantages in the anti - floating engineering of the subway .

At present , there is little research on the anti - floating anchor rod in the present invention , and there is no systematic comparative analysis on the anchoring mechanism and stress distribution law of the anchor end , including the anti - floating anchor rod and the anti - floating anchor rod of the steel bar .
The theory of the deformation characteristics and the new fiber - reinforced plastic anchorage for the anchorage end of the anti - floating anchor rod is not perfect .

In order to study the feasibility of the anti - floating bolt for metro and the application range of it , the bearing characteristics of two kinds of anchor rods are compared and analyzed , and the similarities and differences of the two kinds of anchor rods in the first interface stress distribution law are obtained , and the anchoring capacity of the anchor ends and the failure mechanism are obtained .

In this paper , the load - slip characteristic and a new type of tray nut anchorage are studied by using finite element program ANSYS .

( 1 ) In this paper , the bearing mechanism and the bearing capacity are analyzed in detail . The different damage form and failure mechanism of two kinds of anchor rods are analyzed based on their respective characteristics .

( 2 ) The anchor bolt can be tested by implanting the fiber grating sensor to test the internal force of the anchor rod , and the higher survival rate and the test precision can be obtained through the way of implanting the rib body . The test results provide a detailed analysis of the similarities and differences between the axial force and the shear stress distribution law in the working state of the two anchor rods , and the difference of the stress distribution curve is analyzed .

( 3 ) In the experiment of anchor bolt external anchoring , the failure of the fixture in the traditional anchor rod test is avoided , the complicated treatment and protection measures of the bar body are omitted , and the drawing test is carried out effectively . The experimental results show that the critical anchorage length in the concrete is greatly improved . The anchoring effect and the anchoring efficiency of the new type glass fiber material anchorage are analyzed , and the suggestion of further improvement of the anchorage device is proposed .

( 4 ) In this paper , the load - slip curve in concrete is obtained by means of experimental analysis , and the simulation analysis of the external anchoring end is carried out by ANSYS . It is concluded that the deformation of the inner and outer anchoring ends of the anchor rod is small under the action of the corresponding ultimate load , and the inner and outer anchoring ends of the anchor rod are deformed and are within the allowable range of the project .
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU476

【参考文献】