深基坑桩锚支护体系变形特征研究

Study on Deformation Characteristics of the Anchor Retaining Pile System for Deep Foundation Pit

为研究深基坑中桩锚支护体系变形特性及其空间分布特征,以北京某深基坑为例,采用三维有限差分软件,建立桩锚支护体系分析模型,并将数值分析结果与现行规范计算结果及实测成果进行对比分析。分析结果表明:(1)基坑位移随基坑开挖深度的加大而逐渐增大;(2)阳角部位产生最大变形,阳角效应明显,易发生失稳现象;(3)阴角部位对基坑变形有一定的约束能力,但影响范围很小,在基坑设计中可不考虑阴角约束作用;(4)沿基坑长度方向上,位移分布未呈现明显差别,空间部分效应较不明显;(5)基坑桩顶产生较大的水平位移,而最大水平位移产生在护坡桩桩顶以下至1/2基坑深度范围内,深基坑工程宜加强深层水平位移监测;(6)预应力锚索随空间分布的不同内力无明显差异。

For the study on deformation characteristics and space distribution of pile and anchor shoring system of deep foundation pit,this paper took a deep foundation pit in Beijing as an example,using the three dimensional finite difference software,established an anchor retaining pile system analysis model based on the results of numerical analysis and the comparative analysis calculation results and actual measurement results according to specification. The analysis results showed：（ 1） The displacement of the foundation pit increased with the excavation depth increase gradually;（ 2） The maximum deformation occurred at external angle position and the external angle effect was obvious,therefore,it was easy to lose stability;（ 3） The internal angle part had a certain ability to constrain the deformation of foundation pit,but the scope of the impact was very little,therefore in the design of foundation,the internal angle constraint function could be ignored;（ 4） Along the pit direction,the displacement distribution did not show significant difference,the spatial effect was less obvious;（ 5） The foundation pile top produced large horizontal displacement,and the maximum horizontal displacement of slope protection pile top was generated in the range from top to 1 / 2 depth of excavation of deep foundation pit,strengthen should be done to the monitoring of deep horizontal displacement;（ 6） The internal force of prestressed anchor cable had no obvious difference under various space distribution.