高边坡中含缺陷预应力锚固结构性能退化机理与健康诊断

The issues of anchor structural durability in high slope have become increasingly prominent. Brittle failure of prestressed anchor easily leads to high-speed landslide which often causes serious disaster. Study on anchorage corrosion mechanism and safety damage assessment of anchor structures is urgently needed. The frontier issues such as damage mechanism, performance degradation and diagnosis of anchoring structure under corrosive environment is researched in detail, through the laboratory test, mathematical modeling, electrochemical analysis and intelligent computing. Experimental studies of prestressing strand corrosion will be employed to reveals the law loss of anchorage force and strength injury of prestressed tendon under complex geotechnical environment which contains seepage, oxygen, and etc. The technologies of electrochemical testing, acoustic emission and CT scanning are using to explore the dynamic behavior and characteristics of pitting of defective Pullout tests and elasticity analysis will be carried out to clarify the degradation mechanisms and performance deterioration law of prestressed anchor under corrosive environment. On this basis, response indicators of anchorage structure corrosion will be analyzed, which are used to establishing the degree of corrosion evaluation model based on artificial intelligence algorithm. Ultimately the health diagnostic method of prestressed anchorage structure considering corrosion damage would be proposed. Research may lay the foundation for long-term durability design and safety assessment of anchoring structure, and will help to prevention and control the landslide hazard in major engineering projects, which has important theoretical and engineering application value.

高边坡锚固结构耐久性问题日渐凸显，预应力锚索脆性失效导致的高速滑坡易造成严重的灾害，迫切需要开展锚固结构腐蚀损伤机理与安全评估研究。项目综合运用室内试验、力学建模、电化学分析及智能预测方法，对腐蚀环境下锚固结构损伤机理、性能退化与诊断评估等问题进行研究。在动水、供氧等条件下开展预应力钢绞线腐蚀损伤试验研究，揭示复杂岩土环境下预应力锚筋的锚固力损失与强度损伤规律；引入电化学测试、声发射及CT扫描技术，探索缺陷锚固体的不均匀腐蚀行为及特征；开展锈蚀锚固体拉拔试验与弹性空间解析，阐明腐蚀环境下缺陷锚固结构作用退化机理与性能劣化规律；分析锚固结构腐蚀响应指标，基于智能算法建立腐蚀程度评估模型，提出考虑腐蚀损伤的预应力锚固结构健康诊断方法。研究成果可以为锚固结构耐久性设计与长期安全评估奠定基础，对于重大工程中滑坡灾害的预防与控制具有重要的理论意义和工程应用价值。

为探索预应力锚固结构在复杂岩土环境下的腐蚀损伤机制及性能退化规律，进而提出腐蚀程度诊断与评估模型，综合运用室内模型试验、电化学分析测试、力学建模、智能预测等手段，开展了拟岩土环境下预应力锚杆腐蚀损伤机制、含缺陷预应力锚固结构锈蚀损伤机理、预应力锚固结构腐蚀评估与健康诊断等方面的研究，取得了以下主要研究成果：. （1）通过整理与总结国内外预应力锚固结构腐蚀损伤机理与性能评估研究现状，并与钢筋混凝土结构腐蚀损伤研究作对比分析，探究了高边坡中预应力锚固结构腐蚀损伤的独特性，为确立岩土环境中腐蚀要素与预应力锚固结构性能退化关系奠定了基础；. （2）考虑物理、化学及渗流等工况，在室内构建了复杂岩土环境的多因素条件下（通氧、氯离子、动水）下预应力锚杆加速腐蚀试验，研究了预应力锚杆腐蚀响应指标（物理力学参数、电化学参数）与腐蚀因素之间的关系，揭示了预应力锚杆在多场耦合（应力场-渗流场-化学场，MHC）作用下的腐蚀损伤机理；. （3）通过设计制作预应力丝束电极，对其进行电位/电流扫描、电化学阻抗谱等测试，探究了氯离子在砂浆中的传输扩散机制，基于力学-电化学腐蚀理论建立了预应力砂浆锚杆锈蚀模型；. （4）通过开展含缺陷预应力锚固体锈蚀试验，跟踪缺陷锚固体中筋材点蚀的诱发与锈层发展的腐蚀过程，探究了不同缺陷及锈蚀程度对锚杆力学性能的影响；. （5）基于电化学测试参数及SEM扫描腐蚀坑形貌特征，提出预应力锚固结构腐蚀评估模型。