框架预应力锚托板结构加固高填方边坡设计与数值分析

Design and numerical analyses of high-fill slope strengthened by frame with prestressed anchor-plates

在地质条件复杂的西北山区工程建设中,需要加固大量填方高边坡。为了对填方边坡提供足够的锚固力且保证其整体安全,提出了一种安全稳定、经济简便的新型框架预应力锚托板支挡结构。该种结构适用于加固填方量较大的边坡,且加固效果良好。基于极限平衡算法理论,提出了锚托板抗拔力的计算公式及稳定性计算方法;采用PLAXIS 3D有限元软件,对锚托板的计算方法进行了对比分析;分析了边坡的位移、框架立柱的内力,并采用某实际边坡工程的位移监测数据进行对比,说明了数值模拟结果的合理性,证明框架预应力锚托板结构有效地起到了加固边坡、限制位移的作用。通过对锚托板板身的轴力以及摩阻力强度在施工过程中变化趋势的分析,揭示了该结构与土体的作用机制,并探讨了预应力值大小对该结构的影响。分析结果可为框架预应力锚托板加固高填方边坡的设计提供参考。

Plenty of high-fill slopes need to be strengthened in engineering projects in the mountainous area of the northwestern district of China with complex geological conditions.To provide sufficient anchoring force to fill slopes and to ensure their stabilities,we put forward a new structure of safety,stability,economy and convenience,named frame with prestressed anchor-plates,which suits for reinforcing the slopes with large fill,and whose reinforcement effect is great.Based on the limit equilibrium theory,we proposed the formula for pull-out resistance and the checking calculation method for the stability.Finite element analysis software PLAXIS 3D was applied to compare and verify the results of the proposed method.The displacement of the slope and the internal forces of a column in the frame are further analysed,which explains the rationality of the results of numerical simulation,and proves that the frame with prestressed anchor-plates is effective for strengthening the slope and limiting the displacement by comparing with the displacement data of a slope project.By analysing the variation of axial force and frictional strength during the process of construction,the working mechanism between the plates and the soil is exposed,and the influence of the prestress on the structure is explored.The analysis results guide the design of high-fill slopes strengthened by the frame with prestressed anchor-plates.