基坑复合土钉墙支护变形监测与数值模拟研究

Research on Deformation Monitoring and Numerical Simulation of Composite Soil Nailing Wall Support for Foundation Pit

摘要: 为了研究基坑开挖卸荷对基坑侧壁及周边环境的影响。对郑州市某深基坑工程进行现场监测与MIDAS/GTS数值模拟，研究粉质土层中基坑复合土钉墙支护结构的应力和变形规律。研究结果表明：基坑侧壁水平位移和竖向位移随基坑开挖深度增加呈现先增后稳的趋势，各监测点累积位移量及变化速率均未达到报警值；基坑水平位移场云图呈同心环状扩散特征，基坑竖向位移场云图呈现“浅层位移大、深层衰减快”的特征，基坑剪应力场云图呈现典型的“C”型分布形态；现场监测和数值模拟结果变化趋势较为一致，工程实践验证了该类支护结构在粉土地层基坑支护中的有效性。

Abstract: To investigate the effects of excavation unloading on the sidewalls and surrounding environment of a foundation pit, on-site monitoring and MIDAS/GTS numerical simulation were conducted on a deep foundation pit project in Zhengzhou City. This study focuses on the stress and deformation patterns of the composite soil nail wall support structure in silty soil layers. The findings reveal that as the excavation depth increases, both horizontal and vertical displacements of the pit’s sidewalls initially rise and then stabilize. Notably, the cumulative displacement and rate of change at each monitoring point remain below the alarm threshold. The horizontal displacement field of the foundation pit exhibits a concentric ring-like diffusion pattern, while the vertical displacement field displays significant shallow displacement and rapid attenuation in deeper layers. The shear stress field demonstrates a typical “C” shape distribution. The trends observed in on-site monitoring and numerical simulations align closely, confirming the effectiveness of this support structure in silty soil foundations through practical engineering applications.