极限荷载作用下隧道式锚碇-围岩联合承载机制与承载性能评价方法研究

Anchoring of tunnel type anchor block is not only controlled by unique and complex geological condition, but also strongly affected by bridge load, rainfall and engineering disturbances. Bearing mechanism, failure mode and load transferring mechanism are very complicated. It is urgent to break through in the theoretical and technical problem. The project is based on relevant researching results of the anchor block, depends on suspension bridges of Puli to Xuanwei and Huaping to Lijiang highway in Yunnan province. Through bridge engineering, structure mechanics and rock & soil mechanics multi-disciplinary integration, the classification method of surrounding rock and mechanical patterns of bridge load, anchor block gravity and geotechnical environment load are suggested under coupling effect of geology, rainfall and construction disturbance. Model of anchor block and surrounding rock with consideration of geologic and loads’ characteristics is established. Fail tests, numerical simulations and theoretical models are designed and analyzed. Force and deformation response law of anchor block and rock are analyzed, time effect and spatial effect of force and displacement evolution law are discussed, all these uncover their force transferring mechanism, failure mode and joint bearing mechanism. Correlativity and evolution equations of deformation, strength and bearing safety with surrounding rock stability, structure safety and bridge load are established. Limit condition and failure criterion are discussed. Then the formula of limit bearing capacity is built. The assessment method for bearing properties with dialectical unity of surrounding rock stability, structure safety and bearing design is formed, which can effectively improve the research level of safety control theory and design methods on anchor block in China.

隧道式锚碇的锚固作用既受复杂地质条件的限制，又受桥梁荷载、降雨和施工扰动等因素强烈影响，传力机制、破坏机理和承载机制复杂，是急需突破的理论和技术难题。本项目拟以锚碇相关研究成果为基础，以云南普立-宣威、华坪-丽江高速公路悬索桥为依托工程，通过桥梁工程、结构力学和岩土力学的学科交叉融合，提出地质、降雨和施工扰动耦合作用下围岩力学性能识别方法，统计桥梁、锚碇与围岩等荷载的作用模式，建立锚碇-围岩力学概化模型；通过理论建模、模型试验和数值试验，分析结构与围岩的荷载响应机制和变形演化规律，探讨力和位移响应的时间、空间效应，揭示其传力机制、破坏机理和联合承载机制；构建变形、强度、承载安全与围岩稳定、结构安全与桥梁荷载的相关关系及演化方程，探讨临界条件与失稳判据，建立极限承载力公式，形成围岩、结构和承载安全辩证统一的极限承载性能评价方法，从而有效提升我国桥梁锚碇工程安全控制理论和设计方法的研究水平。

针对大跨径地锚式悬索桥建设面临的隧道式锚碇性能评估难题，极限荷载作用下隧道式锚碇-围岩联合承载机制与承载性能评价方法研究（51778609），利用砼岩界面抗剪断和抗剪切试验结果统计分析，结合规范砼岩界面力学参数的经验统计值，提出一种简单便捷的锚岩系统阶段极限承载力估值公式；利用模型试验和数值试验，揭示了锚岩系统初始界面摩擦承载、中期临界转换、后期夹持岩体剪切承载的联合承载机制；利用构建的锚岩系统简化力学模型，建立基于Mindlin解的锚岩系统极限承载力半解析解计算公式；利用简化力学模型和承载力估值公式，分析了锚岩系统破坏部位及次序和承载性能影响因素的敏感性，论证了锚岩系统短板，揭示锚岩系统承载的阶段极限特征、传力机制及其临界转换机理，提出综合考虑变形和强度、承载安全和围岩稳定、结构安全和桥梁荷载相结合的锚岩系统极限承载性能评价方法和指标体系，方法已用于大吨位锚碇开发和玉楚高速绿汁江特大桥、华丽高速金安金沙江特大桥隧道式锚碇安全评价及优化设计。.全面完成了课题预期目标及相关指标，很好的支撑了依托工程的优化设计和综合安全评估，目前已发表论文10篇，其中EI检索8篇；受理发明专利1项，下阶段继续整理相关专利、软件著作权及英文论文。