高陡边坡预应力锚索预应力损失机理及其试验研究

Prestressed Anchoring technology attaches great importance to solving the stability of steep-high slope engineering. However, anchorage failure accidents caused by prestress loss are common occurrences. Therefore, prestress loss mechanism is discussed in this paper by using comprehensive study methods such as theoretical analysis, numerical simulation, model test and engineering field test. Coupling model of slope rock mass and prestress loss of anchorage is set up and a model test is carried on it after then. As a result, constitutive equation, relaxation equation, and creep equation are deduced as well as the calculation relationship between prestress change and rock mass creep. In addition, the qualitative analysis and quantitative calculation problem of prestress loss during construction process is solved by studying each and every process stage during construction of prestress anchor cables such as pore-forming process, tension process, lock technology and hole sealing grouting process etc. Moreover, calculation formula of channel friction theory considering the effect of channel bending and deviation is deduced by friction at anchorage loop mouth test and field test. Also the calculation problem of channel friction as well as the problem of pore-forming and control of tension are dealt with by establishing the calculation formula within anchor force loss value, slope in opening and tension load. All of these achievements lay a solid theoretical and technical foundation for the design, construction and safety management for steep-high slope of prestressed anchoring engineering as well as prevention and compensation of prestress loss

预应力锚索锚固技术是解决高陡边坡工程稳定性的关键技术，但是因预应力损失而导致锚固失效的工程事故屡见不鲜。运用理论分析、数值模拟、模型试验、工程现场试验相结合的综合研究手段，研究预应力锚索预应力损失机理。建立边坡岩土体与锚索预应力损失之间的耦合效应模型并进行模型试验，推导出其本构方程、松弛方程和蠕变方程，解决预应力变化与岩土体蠕变之间的计算关系；研究预应力锚索施工过程的成孔工艺、张拉工艺、锁定工艺、封孔灌浆工艺等每个工艺阶段，解决施工工艺阶段预应力损失的定性分析与定量计算问题；通过锚口摩阻室内试验和现场试验研究，推导出考虑孔道弯曲和孔道偏差影响的孔道摩阻理论计算公式，建立锚固力损失值与孔斜率及张拉荷载三者之间的计算公式，解决孔道摩阻计算问题和孔道成孔工艺与张拉力控制问题。研究成果可为高陡边坡预应力锚固工程的设计、施工、安全运行管理以及预应力损失的控制与补偿技术提供理论基础和技术手段。

预应力锚索锚固技术是解决高陡边坡工程稳定性的关键技术，由于其预应力损失值和岩土体蠕变量定量计算不准确、测力传感器准确度低等原因，导致锚固失效的工程事故屡见不鲜，因此有必要研究高陡边坡预应力锚索预应力损失机理。采用理论分析、数值模拟相结合的综合研究手段，分析了边坡蠕变与预应力损失之间的耦合效应关系，建立了边坡岩土体与锚索预应力损失之间的耦合效应模型并进行模型试验，推导出其本构方程、松弛方程和蠕变方程。分析了室内、外试验结果，研究了预应力锚索施工工艺的全过程，揭示了各工艺阶段影响因子的影响机理及其锚固力损失的规律和特征，构建了施工阶段锚固力损失的定量计算和定性分析方法，建立了预应力损失的控制与补偿技术，实现了施工过程中实时掌握锚索受力状态解决信息化施工问题，解决了设计过程中及时检验支挡参数实现动态化设计问题，对锚索锚固工程的设计、施工和安全运行管理具有指导意义。通过锚口摩阻试验，揭示了锚口摩阻损失与预应力筋张拉值、锚口锥度、钢绞线直径、千斤顶限位板槽深等相互影响关系，总结了预应力筋在不同状态下的锚口摩阻损失规律与特征，建立了限位板、夹片、钢绞线三者之间最优组合关系。分析了预应力锚索受力状态监测数据，并对据进行了反分析，开发了系列多功能监测仪器及其锚索锚固力受力状态智能化实时监测系统，建立了振弦式传感器制造及量测技术，实现了锚索受力状态数据自动化采集和受力状态变化趋势智能化分析，解决了锚固工程运行管理过程中的安全监测和安全评价问题。