基于“双排桩+预应力锚索”的基坑支护变形研究

Research on Foundation Pit Support Deformation Based on"Double-row Pile + Prestressed Anchor"

在外界荷载作用下,预应力锚索的力学行为较为复杂。为了揭示深基坑预应力锚索的应力变化过程,基于有限元理论,构建“双排桩+预应力锚索”有限元模型,在外界静、动荷载作用下分析预应力锚索的应力变化行为。研究结果表明:随着深度增加,锚索应力数值增大,第5道预应力锚索的最大应力为第1道的1.1倍,下部锚索应力数值比上部锚索大35%~50%;127t车辆荷载产生的动应力比85t车辆大19.1%,与无列车经过相比,锚索应力增加21.5%;基坑5~15m深度横向变形最大,20m以下横向变形逐渐减小。

The mechanical behavior of prestressed anchor is complex under external load.In order to reveal the stress change process of prestressed anchor in deep foundation pit,based on the finite element theory,the finite element model of"double-row pile+prestressed anchor"is built,and the stress change behavior of prestressed anchor is analyzed under external static and dynamic loads.The research results show that:with the increase of depth,the stress value of anchor increases,the maximum stress of the fifth prestressed anchor is 1.1 times that of the first,and the stress value of the lower anchor is 35%~50%larger than that of the upper anchor.The dynamic stress generated by the load of 127t vehicle is 19.1%greater than that of 85t vehicle,and the anchor stress increases by 21.5%compared with that without train.The lateral deformation of the foundation pit at a depth of 5~15m is the largest,and that below 20m gradually decreases.