地震作用下边坡加固的压力分散型锚固系统的动力响应

The long-term performance of anchoring system is an important factor influencing safety of many major construction projects. The anchoring systems of slope are generally designed based on limit equilibrium method at present, and they are designed according to past experience that it spares some safety margin to consider the force changes of anchor cables and their influence on slope safety during the service of anchoring system, without considering the difference of anchor force among different parts of the slope during service, especially for the pressure-dispersive anchor cables that start widely in recent years, the relative achievement is nearly blank. This application is aimed at studying earthquakes whose character is bringing about force changes of slope anchor cables in service，the dynamic response of pressure-dispersive anchoring system of slope reinforcement in earthquake action is systematically studied through site investigation, model experiment, shaking table test and numerical analysis. Some laws on the force change of pressure-dispersive anchor cables and their anchor fixed length in different parts of the slope with typical geological stratum and typical structure under different seismic intensity action are given out, and the possible failure modes of pressure-dispersive anchoring system of slope reinforcement under earthquake are summarized, and then the design methods and safety contral measures of slope anchoring system considering seismic effect are provided. Research results have important theoretical significance and application value on slope (landslide) engineering protection.

锚固系统的长期性能是影响许多重大工程安全的重要因素。目前的边坡锚固系统一般基于极限平衡法进行设计，设计时仅根据经验给予一定的安全富裕来考虑锚固系统在服役期间锚索的受力变化及其对安全的影响，更没有考虑不同边坡部位锚索在服役期间受力的可能差异，尤其对近年来开始广泛应用的压力分散型锚索来说，其相关研究更是空白。本申请主要针对引起在役环境边坡锚索受力变化的主要因素地震，通过现场调查、室内试验、模型振动台试验与数值分析等方法系统地研究边坡加固的压力分散型锚固系统在地震作用下的动力响应，给出典型地层、典型结构边坡不同部位的压力分散型锚索在不同地震烈度作用下的受力变化规律以及锚固段的传力机制，总结边坡加固的压力分散型锚固系统在地震作用下的可能破坏模式，提出考虑地震效应的边坡锚固系统的设计方法与在役边坡锚固系统的安全控制措施。研究成果对边坡（滑坡）工程防护有重要理论意义与工程应用价值。

锚固系统的性能影响许多重大工程的安全，围绕边坡工程锚固机理与地震动响应问题，对地震作用下边坡加固的压力型锚索动态响应、锚索（杆）锚固机理、预应力锚索加固边坡抗震稳定性及可靠度、应力波在边坡节理中的传播效应及振动损伤等开展了系统研究。主要研究内容及成果：1）基于数值模拟方法研究了地震作用下不同影响因素对边坡压力型锚索的动力影响，获得了边坡锚索锚固段界面剪应力和注浆体轴应力在地震作用下的动态响应规律；应用拟静力分析方法，基于Mindlin解推导出了地震作用下压力型锚索体系中注浆体的压应力表达式和注浆体与锚索孔壁之间的剪应力表达式；给出了地震作用下压力型锚索锚固段设计方法。2）通过4种不同形式锚固段锚索（杆）抗拔的室内透明土模型试验，获得了各锚索（杆）随锚固段上移对周围土体的扰动规律、锚索（杆）位移与锚固力变化曲线，推导出了连续球体形锚固段的抗拔荷载计算公式；开展室内模型试验，揭示了顺层岩质边坡因滑面力学性能劣化引起的不同边坡位置锚索的受力变化规律，并建立了锚索预应力增量关系式。3）基于理论分析，提出了考虑滑坡体变形能耗的边坡稳定性评价极向条分法、预应力锚索加固各向异性非均质边坡稳定性极限分析水平条分法、基于极限分析的边坡实时动态Newmark滑块位移法以及基于全局极限响应面的预应力锚索加固边坡抗震可靠度分析方法。4）考虑节理岩体的蠕变和应力松弛特性，提出了黏弹性节理的等效标准线性固体模型，采用位移不连续理论，推导了应力波入射黏弹性节理的传播方程，获得了应力波入射黏弹性节理的传播规律；基于顺层边坡爆破开挖的声波测试结合坡面的振动速度监测，获取了坡体不同深度的声速变化及不同位置的振动速度，给出了不同药量下单次和多次爆破的坡体损伤范围以及振动速度的衰减规律。研究成果丰富与发展了边坡工程锚固机理与地震动响应理论，可为边坡工程加固设计及抗震稳定性分析提供参考。