桩锚支护结构水平位移的简化算法

A simplified algorithm of lateral displacements of pile-anchor retaining structures

桩锚支护结构在基坑和边坡围护工程中有着广泛的应用,设计阶段对支护结构的水平变形作出准确预测意义重大。根据国内多地基坑工程围护墙变形实测结果,建立桩锚支护结构水平位移的计算模型和计算假定,计算基坑围护墙在各外力作用下的变形,利用弹性叠加法得出桩锚支护结构围护墙深层水平位移表达式,联立锚杆刚度方程求解出其中的参数,最终得到水平位移的简化计算结果。该简化算法适用于围护墙底变形较小的桩锚支护结构计算,通过温州某基坑工程实例对比,围护墙变形计算结果与实测数据较为吻合,验证了该简化算法的适用性。

Pile-anchor retaining structure is widely used in foundation pit engineering and side slope engineering in many countries, especially in China and Japan. In contrast to strut, pile-anchor retaining structure has several typical features and advantages. It doesn＇t occupy the internal space of the foundation pit and the project cost is much lower. With the technology of prestress, engineers can control the deformation of the retaining wall actively which is impossible in inner supporting structures. Accurate prediction of the lateral displacements of the retaining structure is very important in the design stage. An analytical evaluation model and several calculation assumptions of lateral displacements of pile-anchor retaining structure are set up according to measured data of several foundation pits from different cities in China. The deformation of the retaining wall under each external force is calculated. The expression of lateral displacement versus depth is solved by means of quasi-elastic summation; and the parameters are obtained from the stiffness equation of the anchors. The analytical evaluation of the lateral deformation curve is then completed. The simplified method is suitable for braced excavation with small displacement at the bottom of the retaining wall. The applicability of the proposed method is validated by practical engineering.