侵蚀环境下预应力GFRP锚杆结构的应力松弛模型

It is well recognized that corrosion of steel soil nail is a significant threat to the safety of reinforcement slope structure, and a lot of efforts have been made by researchers all over the world to find substitutes to the steel in harsh environment. The glass fiber reinforced polymer (GFRP) bar, because of its high tensile strength and low modulus, is found ideal to work as pre-stressed anchor. Together with its good corrosion resistance and reasonable cost, GFRP bar has become one of the optimum alternatives to the steel anchor, and there are already attempts of using GFRP bars as anchors in temporary projects both in China and abroad. However, there are still very limited studies on the application of GFRP bar to the permanent anchorage structure. In this study, lab creep tests on the GFRP bars and GFRP grip system are carried out with different dimension, loading, temperature and corrosion conditions. Based on the testing results and the theoretical creep model of homogeneous materials, the creep models for GFRP bars and GFRP grip system with different influence factors will be developed. In addition, the GFRP soil nail element will be subjected to the stress relaxation tests under different conditions in dimension, loading, temperature and corrosion, and the stress relaxation model for the bond system of GFRP soil nail element will be established according to the testing results. Finally, the stress relaxation model for the whole GFRP soil nail element structures with different affecting factors will be built by combining the creep models for GFRP bars and GFRP grip system and the stress relaxation model for the bond system of GFRP soil nail element. This study will make major progress to the understanding of long-term properties of GFRP soil nail anchored structures.

钢筋锚杆锈蚀构成了边坡锚固结构的安全隐患。玻璃纤维增强聚合物（GFRP）筋抗拉强度大、模量低、耐腐蚀性强、性价比高，预应力GFRP锚杆有利于发挥材料的优势，成为解决途径之一。国际国内已有GFRP锚杆加固的临时性工程，而用于永久性锚杆结构的依据还不充分。本项研究基于均质材料的蠕变理论模型，根据复合材料属性和不同尺寸、荷载、温度和侵蚀条件的GFRP筋蠕变实验，建立多因素影响的GFRP筋和GFRP筋锚固系统的蠕变模型；根据不同尺寸、荷载、温度和侵蚀条件的GFRP筋锚杆结构应力松弛实验，建立多因素影响的GFRP筋胶结体的应力松弛模型；综合GFRP筋及其锚固系统的蠕变模型和GFRP筋胶结体的应力松弛模型，最终形成有侵蚀、荷载、温度、尺寸影响的GFRP筋锚杆结构的应力松弛模型。研究成果对GFRP筋锚杆在边坡加固工程中的科学应用有重要意义。

钢筋锚杆锈蚀构成了边坡锚固结构的安全隐患，玻璃纤维聚合物（GFRP）筋抗拉强度大、模量低、耐腐蚀性强、性价比高，预应力GFRP筋锚杆有利于发挥材料的优势，成为解决途径之一，研究其耐久性能和应力松弛模型有现实意义和科学价值。GFRP筋锚杆结构对于长期荷载、循环荷载、腐蚀条件、温度变化、湿度变化的反应和发展规律，均需进一步研究。.本项目的研究思路是，依据不同尺寸、荷载、温度、侵蚀条件的GFRP筋蠕变实验修正理论模型，建立多因素影响的GFRP筋的蠕变模型和GFRP筋锚固系统的蠕变模型。依据不同尺寸、荷载、温度、侵蚀条件的GFRP筋锚杆单元结构应力松弛实验，建立多因素影响的GFRP筋胶结体的应力松弛模型。联合GFRP筋、GFRP筋锚固系统的蠕变模型和GFRP筋胶结体的应力松弛模型，建立有侵蚀、荷载、温度、尺寸影响的GFRP筋锚杆结构的应力松弛模型。通过理论和实验研究取得了重要进展和成果。. 研发出FRP筋锚头锚固装置，开发了新型耐碱腐蚀FRP筋，即外覆玄武岩纤维的玻璃纤维聚合物（B-GFRP）筋，建立了FRP筋拉伸、黏结等实验条件，测试了大直径GFRP筋的应力应变特征，取得了非腐蚀环境下GFRP筋锚固系统的应力松弛模型，提出了确定GFRP筋锚杆的端锚黏结长度的计算方法，确定了GFRP筋锚杆与框架梁连接方式。. 开发出预应力GFRP锚杆结构荷载锁定装置并通过现场试验验证了可靠性，揭示了预应力喷砂GFRP筋锚杆的黏结损伤规律，据此提出了锚杆预应力张拉的控制方法，建立了非腐蚀环境全长黏结大直径B-GFRP筋锚杆结构单元应力松弛模型。. 开发了可控制腐蚀、温度和应力条件的B-GFRP筋锚固系统实验装置，测试了应力腐蚀下B-GFRP筋锚固系统的应力松弛率水平，提出了腐蚀环境对锚固系统的影响规律，评价了B-GFRP筋在应力腐蚀环境下的耐久性特征。