Abstract Jet grout piles (JGP) is a ground improvement method that is constructed beneath the final excavation level to prevent basal heave instability, control wall deflections and reduce the strut loads for braced excavations in deep deposits of soft clay. This paper presents the effects of JGP on the wall deflections and strut forces for deep excavations. Firstly, finite element analysis calibrated by an excavation case history improved by JGP is carried out, followed by parametric studies that investigate the effects of various JGP geometric and mechanical properties on the excavation performances. The numerical analyses indicate that increasing the number of piles and the areal extent of reinforcement area, as well as decreasing the pile spacing, can significantly reduce the wall deflections and strut forces for excavation in weak clay. Additionally, use of a thicker layer of jet grout slab without the jet grout pile system is also studied. The feasibility of reducing one level of struts for sake of construction time and costs while adjusting the jet grout piles’ layout to maintain the stability is also discussed.

中文翻译：

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软土支撑开挖喷射灌浆桩性能数值研究

摘要 喷射灌浆桩（JGP）是一种在最终开挖平面以下施工的地基改良方法，用于防止基坑失稳、控制墙体挠度并减少软粘土深部支撑开挖的支柱载荷。本文介绍了 JGP 对深基坑墙体挠度和支柱力的影响。首先，通过 JGP 改进的开挖案例历史校准进行有限元分析，然后进行参数研究，研究各种 JGP 几何和机械特性对开挖性能的影响。数值分析表明，增加桩数和加固区的面积，减小桩间距，可以显着降低弱粘土开挖的墙体挠度和支柱力。此外，还研究了在没有喷射灌浆桩系统的情况下使用较厚的喷射灌浆板。还讨论了在调整喷射灌浆桩布局以保持稳定性的同时，为了节省施工时间和成本而减少一层支柱的可行性。