地震作用下框架预应力锚杆加固黄土边坡破坏机理及稳定性分析

In recent years, the reinforcement technology of frame with pre-stressed anchors was applied more and more widely in slope engineering, the seismic reaction analysis of the reinforced slope was also developed gradually. However, in the failure mechanism and stability analysis of losse slope reinforced by frame with pre-stressed anchors under seismic, it is obviously insufficient. Thus, it has important theoretical significance and practical value in engineering due to this research.Based on the shaking table test and theoretical analysis, the seismic response model of losse slope reinforced by frame with pre-stressed anchors is established, and the dynamic characteristics of the reinforced slope are also analyzed. Therefore, the reinforcement mechanism of losse slope reinforced by frame with pre-stressed anchors under earthquake conditions are demonstrated on the basis of the response regularity comparisons between the unreinforced and reinforced slopes. In addition, the seismic failure-instability model of losse slope reinforced by frame with pre-stressed anchors is established according to the seismic failure modes and limit danymic strain method, and then the failure mechanism of the reinforced slope is revealed. At last, the seismic stability analysis model of losse slope reinforced by frame with pre-stressed anchors are proposed based on the deformation and failure characteristics.The researth can enhance the theory of seismic resistance and disaster mitigation control, and can be valuable to the seismic resistance for the reinforced slope engineering in loess area.

近年来，框架预应力锚杆加固技术在黄土边坡工程中的应用日益广泛，框架预应力锚杆加固边坡的地震动力分析也得到了一定的发展，但是在地震作用下框架预应力锚杆加固黄土边坡的失稳破坏机理及稳定性分析方面的研究还比较欠缺，开展本课题研究具有重要的理论意义和工程实用价值。本项目拟基于振动台试验和理论分析等方法，建立考虑锚杆预应力的框架预应力锚杆加固黄土边坡地震动响应模型，分析加固边坡的动力特性；通过对比分析素土边坡和加固边坡的动力响应规律，明确地震作用下框架预应力锚杆加固黄土边坡的加固机理；根据加固黄土边坡的地震破坏模式，采用极限动应变法，建立地震作用下框架预应力锚杆加固黄土边坡破坏失稳模型，揭示加固边坡的地震动破坏机理；基于变形破坏特点，建立框架预应力锚杆加固黄土边坡地震稳定性分析模型及评价方法。研究成果将丰富框架预应力锚杆加固边坡的抗震减灾控制理论，对黄土地区加固边坡工程抗震有重要的实用价值。

针对黄土边坡工程中框架预应力锚杆加固边坡在地震作用下的失稳破坏机理及稳定性分析方面的研究还比较欠缺的问题，本项目根据地震作用下框架预应力锚杆加固边坡的变形特点，采用定性分析与定量分析相结合的方法，借助大型振动台模型试验、理论分析及有限元数值模拟研究了地震作用下框架预应力锚杆加固黄土边坡的动力响应。首先基于等效质量弹簧模型，考虑蠕变土体与预应力锚杆的耦合效应，建立了地震作用下框架预应力锚杆加固的黄土边坡在考虑坡高效应时的动力计算模型。其次基于柔性支挡结构减震耗能机理，考虑框架预应力锚杆对边坡的支护作用，通过能量法建立了框架预应力锚杆加固黄土边坡的地震位移模型，求解了框架预应力锚杆加固黄土边坡的永久位移，并对框架预应力锚杆加固的边坡永久位移进行了探讨。最后，从锚杆-框架-土体协同作用入手研究了地震作用下框架预应力锚杆加固黄土边坡变形与稳定性控制机理。通过以上研究揭示了框架预应力锚杆加固边坡的地震破坏特性及破坏机理，为框架预应力锚杆加固边坡的地震稳定性分析与设计提供科学依据，丰富框架预应力锚杆加固边坡的理论体系。