Xia Rongyu, Zhao Zhizhong, Wang Risheng, Xu Maolin, Ye Shujun, Xu Meng
School of Transportation Civil Engineering, Shandong Jiaotong University, Jinan 250357, China.
Shandong Dongtai Engineering Consulting Co., Zibo 255000, China.
Sensors (Basel). 2024 Jan 10;24(2):426. doi: 10.3390/s24020426.
To investigate the impact of underground water seepage and soil stress fields on the deformation of excavation and support structures, this study initially identified the key influencing factors on excavation deformation. Subsequently, through a finite element simulation analysis using Plaxis, this study explored the effects of critical factors, such as the excavation support form, groundwater lowering depth, permeability coefficient, excavation layer, and sequence on excavation deformation. Furthermore, a comprehensive consideration of various adverse factors was integrated to establish excavation support early warning thresholds, and optimal dewatering strategies. Finally, this study validated the simulation analysis through an on-site in situ testing with wireless sensors in the context of a physical construction site. The research results indicate that the internal support system within the excavation piles exhibited better stability compared to the external anchor support system, resulting in a 34.5% reduction in the overall deformation. Within the internal support system, the factors influencing the excavation deformation were ranked in the following order: water level (35.5%) > permeability coefficient (17.62%) > excavation layer (11.4%). High water levels, high permeability coefficients, and multi-layered soils were identified as the most unfavorable factors for excavation deformation. The maximum deformation under the coupled effect of these factors was established as the excavation support early warning threshold, and the optimal dewatering strategy involved lowering the water level at the excavation to 0.5 m below the excavation face. The on-site in situ monitoring data obtained through wireless sensors exhibited low discrepancies compared to the finite element simulation data, indicating the high precision of the finite element model for considering the fluid-structure interaction.
为研究地下水渗流和土应力场对基坑开挖与支护结构变形的影响，本研究首先识别了影响基坑开挖变形的关键因素。随后，通过使用Plaxis进行有限元模拟分析，本研究探讨了诸如开挖支护形式、降水深度、渗透系数、开挖层数和开挖顺序等关键因素对基坑开挖变形的影响。此外，综合考虑各种不利因素，建立了基坑开挖支护预警阈值和最优降水策略。最后，本研究通过在实际施工现场使用无线传感器进行现场原位测试，验证了模拟分析结果。研究结果表明，与外部锚杆支护体系相比，基坑桩内的内支撑体系表现出更好的稳定性，整体变形减少了34.5%。在内支撑体系中，影响基坑开挖变形的因素排序如下：水位（35.5%）＞渗透系数（17.62%）＞开挖层数（11.4%）。高水位、高渗透系数和多层土被确定为基坑开挖变形最不利的因素。将这些因素耦合作用下的最大变形设定为基坑开挖支护预警阈值，最优降水策略是将基坑处的水位降至开挖面以下0.5m。通过无线传感器获得的现场原位监测数据与有限元模拟数据相比差异较小，表明考虑流固耦合的有限元模型具有较高精度。
