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Research overview on the mechanism of deformation induced by excavation dewatering and countermeasures in soft soil stratum in Tianjin
- ZHENG Gang, CHENG Xuesong, LI Qinghan, QIU Jun, CHENG Wenlong, ZHOU Shilong
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Journal of Shandong University(Engineering Science). 2026, 56(3):
1-14.
doi:10.6040/j.issn.1672-3961.0.2024.278
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In view of the characteristics of obvious aquifer leakage and low permeability of aquifers in Tianjin, the study investigated the deformation mechanism and control methods caused by excavation dewatering based on actual engineering projects. The different mechanisms of retaining structure deformation, soil settlement, and adjacent tunnel deformation induced by two types of excavation dewatering, drainage dewatering and pressure relief dewatering, were comparatively analysed. The significant influences of aquifer leakage on deformation and its mechanism were revealed. The control strategies for deformation caused by dewatering were divided into two major categories, “optimization for excavation dewatering system” and “active control with groundwater recharge”. The first strut and segmented dewatering proved effective in controlling dewatering-induced deformation of retaining structures in different strata. The deep-shallow-well scheme significantly reduced settlement outside excavations with leaky aquifers compared to the traditional mixed-well scheme. Field tests and engineering applications indicated that groundwater recharge also demonstrates effective for water level control in silt and silty sand aquifers in regions like Tianjin. Moreover, the studies revealed distinctions between dewatering and recharge theories, such as recharge cones and well losses, and proposed efficient recharge technologies for settlement control, including pressurized recharge and interlayer recharge. To address the plugging issues during groundwater recharge in silt and silty sand aquifers, the mechanisms of plugging, such as particle migration, had been elucidated. Moreover, the anti-plugging recharge technologies, including combined recharge, optimization of well spacing, and pressurization of neighboring wells combined with redevelopment were proposed. This paper summarized the mechanisms of deformation induced by excavation dewatering, the optimization of dewatering system, and theories and applications of groundwater recharge. The aim of this paper was to provide references for controlling the environmental influences caused by excavation dewatering in soft soil, thereby contributing to urban construction safety and the protection of water resources.