DEWATERING DESIGN AND NUMERICAL ANALYSIS OF DEEP FOUNDATION PITS FOR SUBWAY CONSTRUCTION IN SOFT SOIL AREAS
Deep foundation pit dewatering in water-rich soft soil areas presents significant challenges in pit engi-neering,often using a combination of diaphragm walls and plain concrete walls as a water barrier.However,if de-fects occur in the inner diaphragm wall during excavation,the water barrier is prone to issues such as sidewall leak-age and piping under high hydraulic pressure.This study is based on a deep foundation pit project for a subway ven-tilation shaft in Nanjing,employing numerical simulations and on-site measurements to analyze dewatering effective-ness when part of the water barrier fails.The findings indicate that both the diaphragm wall and plain concrete wall may have flaws in actual projects,and the groundwater outside the pit may replenish the groundwater inside.In such cases,activating dewatering wells between the two walls can effectively lower the groundwater level while reasonably controlling the impact of dewatering on ground settlement.The conclusions drawn from this study provide valuable references for similar engineering projects.
water rich strata in soft soil areasdeep foundation pit dewateringland subsidence
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